001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.lang3;
018
019import java.io.UnsupportedEncodingException;
020import java.nio.charset.Charset;
021import java.text.Normalizer;
022import java.util.ArrayList;
023import java.util.Arrays;
024import java.util.HashSet;
025import java.util.Iterator;
026import java.util.List;
027import java.util.Locale;
028import java.util.Objects;
029import java.util.Set;
030import java.util.StringJoiner;
031import java.util.function.Supplier;
032import java.util.regex.Pattern;
033
034import org.apache.commons.lang3.function.ToBooleanBiFunction;
035
036/**
037 * <p>Operations on {@link java.lang.String} that are
038 * {@code null} safe.</p>
039 *
040 * <ul>
041 *  <li><b>IsEmpty/IsBlank</b>
042 *      - checks if a String contains text</li>
043 *  <li><b>Trim/Strip</b>
044 *      - removes leading and trailing whitespace</li>
045 *  <li><b>Equals/Compare</b>
046 *      - compares two strings in a null-safe manner</li>
047 *  <li><b>startsWith</b>
048 *      - check if a String starts with a prefix in a null-safe manner</li>
049 *  <li><b>endsWith</b>
050 *      - check if a String ends with a suffix in a null-safe manner</li>
051 *  <li><b>IndexOf/LastIndexOf/Contains</b>
052 *      - null-safe index-of checks
053 *  <li><b>IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut</b>
054 *      - index-of any of a set of Strings</li>
055 *  <li><b>ContainsOnly/ContainsNone/ContainsAny</b>
056 *      - checks if String contains only/none/any of these characters</li>
057 *  <li><b>Substring/Left/Right/Mid</b>
058 *      - null-safe substring extractions</li>
059 *  <li><b>SubstringBefore/SubstringAfter/SubstringBetween</b>
060 *      - substring extraction relative to other strings</li>
061 *  <li><b>Split/Join</b>
062 *      - splits a String into an array of substrings and vice versa</li>
063 *  <li><b>Remove/Delete</b>
064 *      - removes part of a String</li>
065 *  <li><b>Replace/Overlay</b>
066 *      - Searches a String and replaces one String with another</li>
067 *  <li><b>Chomp/Chop</b>
068 *      - removes the last part of a String</li>
069 *  <li><b>AppendIfMissing</b>
070 *      - appends a suffix to the end of the String if not present</li>
071 *  <li><b>PrependIfMissing</b>
072 *      - prepends a prefix to the start of the String if not present</li>
073 *  <li><b>LeftPad/RightPad/Center/Repeat</b>
074 *      - pads a String</li>
075 *  <li><b>UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize</b>
076 *      - changes the case of a String</li>
077 *  <li><b>CountMatches</b>
078 *      - counts the number of occurrences of one String in another</li>
079 *  <li><b>IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable</b>
080 *      - checks the characters in a String</li>
081 *  <li><b>DefaultString</b>
082 *      - protects against a null input String</li>
083 *  <li><b>Rotate</b>
084 *      - rotate (circular shift) a String</li>
085 *  <li><b>Reverse/ReverseDelimited</b>
086 *      - reverses a String</li>
087 *  <li><b>Abbreviate</b>
088 *      - abbreviates a string using ellipses or another given String</li>
089 *  <li><b>Difference</b>
090 *      - compares Strings and reports on their differences</li>
091 *  <li><b>LevenshteinDistance</b>
092 *      - the number of changes needed to change one String into another</li>
093 * </ul>
094 *
095 * <p>The {@code StringUtils} class defines certain words related to
096 * String handling.</p>
097 *
098 * <ul>
099 *  <li>null - {@code null}</li>
100 *  <li>empty - a zero-length string ({@code ""})</li>
101 *  <li>space - the space character ({@code ' '}, char 32)</li>
102 *  <li>whitespace - the characters defined by {@link Character#isWhitespace(char)}</li>
103 *  <li>trim - the characters &lt;= 32 as in {@link String#trim()}</li>
104 * </ul>
105 *
106 * <p>{@code StringUtils} handles {@code null} input Strings quietly.
107 * That is to say that a {@code null} input will return {@code null}.
108 * Where a {@code boolean} or {@code int} is being returned
109 * details vary by method.</p>
110 *
111 * <p>A side effect of the {@code null} handling is that a
112 * {@code NullPointerException} should be considered a bug in
113 * {@code StringUtils}.</p>
114 *
115 * <p>Methods in this class include sample code in their Javadoc comments to explain their operation.
116 * The symbol {@code *} is used to indicate any input including {@code null}.</p>
117 *
118 * <p>#ThreadSafe#</p>
119 * @see java.lang.String
120 * @since 1.0
121 */
122//@Immutable
123public class StringUtils {
124
125    private static final int STRING_BUILDER_SIZE = 256;
126
127    // Performance testing notes (JDK 1.4, Jul03, scolebourne)
128    // Whitespace:
129    // Character.isWhitespace() is faster than WHITESPACE.indexOf()
130    // where WHITESPACE is a string of all whitespace characters
131    //
132    // Character access:
133    // String.charAt(n) versus toCharArray(), then array[n]
134    // String.charAt(n) is about 15% worse for a 10K string
135    // They are about equal for a length 50 string
136    // String.charAt(n) is about 4 times better for a length 3 string
137    // String.charAt(n) is best bet overall
138    //
139    // Append:
140    // String.concat about twice as fast as StringBuffer.append
141    // (not sure who tested this)
142
143    /**
144     * A String for a space character.
145     *
146     * @since 3.2
147     */
148    public static final String SPACE = " ";
149
150    /**
151     * The empty String {@code ""}.
152     * @since 2.0
153     */
154    public static final String EMPTY = "";
155
156    /**
157     * A String for linefeed LF ("\n").
158     *
159     * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences
160     *      for Character and String Literals</a>
161     * @since 3.2
162     */
163    public static final String LF = "\n";
164
165    /**
166     * A String for carriage return CR ("\r").
167     *
168     * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences
169     *      for Character and String Literals</a>
170     * @since 3.2
171     */
172    public static final String CR = "\r";
173
174    /**
175     * Represents a failed index search.
176     * @since 2.1
177     */
178    public static final int INDEX_NOT_FOUND = -1;
179
180    /**
181     * <p>The maximum size to which the padding constant(s) can expand.</p>
182     */
183    private static final int PAD_LIMIT = 8192;
184
185    /**
186     * Pattern used in {@link #stripAccents(String)}.
187     */
188    private static final Pattern STRIP_ACCENTS_PATTERN = Pattern.compile("\\p{InCombiningDiacriticalMarks}+"); //$NON-NLS-1$
189
190    /**
191     * <p>Abbreviates a String using ellipses. This will turn
192     * "Now is the time for all good men" into "Now is the time for..."</p>
193     *
194     * <p>Specifically:</p>
195     * <ul>
196     *   <li>If the number of characters in {@code str} is less than or equal to
197     *       {@code maxWidth}, return {@code str}.</li>
198     *   <li>Else abbreviate it to {@code (substring(str, 0, max-3) + "...")}.</li>
199     *   <li>If {@code maxWidth} is less than {@code 4}, throw an
200     *       {@code IllegalArgumentException}.</li>
201     *   <li>In no case will it return a String of length greater than
202     *       {@code maxWidth}.</li>
203     * </ul>
204     *
205     * <pre>
206     * StringUtils.abbreviate(null, *)      = null
207     * StringUtils.abbreviate("", 4)        = ""
208     * StringUtils.abbreviate("abcdefg", 6) = "abc..."
209     * StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
210     * StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
211     * StringUtils.abbreviate("abcdefg", 4) = "a..."
212     * StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
213     * </pre>
214     *
215     * @param str  the String to check, may be null
216     * @param maxWidth  maximum length of result String, must be at least 4
217     * @return abbreviated String, {@code null} if null String input
218     * @throws IllegalArgumentException if the width is too small
219     * @since 2.0
220     */
221    public static String abbreviate(final String str, final int maxWidth) {
222        return abbreviate(str, "...", 0, maxWidth);
223    }
224
225    /**
226     * <p>Abbreviates a String using ellipses. This will turn
227     * "Now is the time for all good men" into "...is the time for..."</p>
228     *
229     * <p>Works like {@code abbreviate(String, int)}, but allows you to specify
230     * a "left edge" offset.  Note that this left edge is not necessarily going to
231     * be the leftmost character in the result, or the first character following the
232     * ellipses, but it will appear somewhere in the result.
233     *
234     * <p>In no case will it return a String of length greater than
235     * {@code maxWidth}.</p>
236     *
237     * <pre>
238     * StringUtils.abbreviate(null, *, *)                = null
239     * StringUtils.abbreviate("", 0, 4)                  = ""
240     * StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
241     * StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
242     * StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
243     * StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
244     * StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
245     * StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
246     * StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
247     * StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
248     * StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
249     * StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
250     * StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
251     * </pre>
252     *
253     * @param str  the String to check, may be null
254     * @param offset  left edge of source String
255     * @param maxWidth  maximum length of result String, must be at least 4
256     * @return abbreviated String, {@code null} if null String input
257     * @throws IllegalArgumentException if the width is too small
258     * @since 2.0
259     */
260    public static String abbreviate(final String str, final int offset, final int maxWidth) {
261        return abbreviate(str, "...", offset, maxWidth);
262    }
263
264    /**
265     * <p>Abbreviates a String using another given String as replacement marker. This will turn
266     * "Now is the time for all good men" into "Now is the time for..." if "..." was defined
267     * as the replacement marker.</p>
268     *
269     * <p>Specifically:</p>
270     * <ul>
271     *   <li>If the number of characters in {@code str} is less than or equal to
272     *       {@code maxWidth}, return {@code str}.</li>
273     *   <li>Else abbreviate it to {@code (substring(str, 0, max-abbrevMarker.length) + abbrevMarker)}.</li>
274     *   <li>If {@code maxWidth} is less than {@code abbrevMarker.length + 1}, throw an
275     *       {@code IllegalArgumentException}.</li>
276     *   <li>In no case will it return a String of length greater than
277     *       {@code maxWidth}.</li>
278     * </ul>
279     *
280     * <pre>
281     * StringUtils.abbreviate(null, "...", *)      = null
282     * StringUtils.abbreviate("abcdefg", null, *)  = "abcdefg"
283     * StringUtils.abbreviate("", "...", 4)        = ""
284     * StringUtils.abbreviate("abcdefg", ".", 5)   = "abcd."
285     * StringUtils.abbreviate("abcdefg", ".", 7)   = "abcdefg"
286     * StringUtils.abbreviate("abcdefg", ".", 8)   = "abcdefg"
287     * StringUtils.abbreviate("abcdefg", "..", 4)  = "ab.."
288     * StringUtils.abbreviate("abcdefg", "..", 3)  = "a.."
289     * StringUtils.abbreviate("abcdefg", "..", 2)  = IllegalArgumentException
290     * StringUtils.abbreviate("abcdefg", "...", 3) = IllegalArgumentException
291     * </pre>
292     *
293     * @param str  the String to check, may be null
294     * @param abbrevMarker  the String used as replacement marker
295     * @param maxWidth  maximum length of result String, must be at least {@code abbrevMarker.length + 1}
296     * @return abbreviated String, {@code null} if null String input
297     * @throws IllegalArgumentException if the width is too small
298     * @since 3.6
299     */
300    public static String abbreviate(final String str, final String abbrevMarker, final int maxWidth) {
301        return abbreviate(str, abbrevMarker, 0, maxWidth);
302    }
303    /**
304     * <p>Abbreviates a String using a given replacement marker. This will turn
305     * "Now is the time for all good men" into "...is the time for..." if "..." was defined
306     * as the replacement marker.</p>
307     *
308     * <p>Works like {@code abbreviate(String, String, int)}, but allows you to specify
309     * a "left edge" offset.  Note that this left edge is not necessarily going to
310     * be the leftmost character in the result, or the first character following the
311     * replacement marker, but it will appear somewhere in the result.
312     *
313     * <p>In no case will it return a String of length greater than {@code maxWidth}.</p>
314     *
315     * <pre>
316     * StringUtils.abbreviate(null, null, *, *)                 = null
317     * StringUtils.abbreviate("abcdefghijklmno", null, *, *)    = "abcdefghijklmno"
318     * StringUtils.abbreviate("", "...", 0, 4)                  = ""
319     * StringUtils.abbreviate("abcdefghijklmno", "---", -1, 10) = "abcdefg---"
320     * StringUtils.abbreviate("abcdefghijklmno", ",", 0, 10)    = "abcdefghi,"
321     * StringUtils.abbreviate("abcdefghijklmno", ",", 1, 10)    = "abcdefghi,"
322     * StringUtils.abbreviate("abcdefghijklmno", ",", 2, 10)    = "abcdefghi,"
323     * StringUtils.abbreviate("abcdefghijklmno", "::", 4, 10)   = "::efghij::"
324     * StringUtils.abbreviate("abcdefghijklmno", "...", 6, 10)  = "...ghij..."
325     * StringUtils.abbreviate("abcdefghijklmno", "*", 9, 10)    = "*ghijklmno"
326     * StringUtils.abbreviate("abcdefghijklmno", "'", 10, 10)   = "'ghijklmno"
327     * StringUtils.abbreviate("abcdefghijklmno", "!", 12, 10)   = "!ghijklmno"
328     * StringUtils.abbreviate("abcdefghij", "abra", 0, 4)       = IllegalArgumentException
329     * StringUtils.abbreviate("abcdefghij", "...", 5, 6)        = IllegalArgumentException
330     * </pre>
331     *
332     * @param str  the String to check, may be null
333     * @param abbrevMarker  the String used as replacement marker
334     * @param offset  left edge of source String
335     * @param maxWidth  maximum length of result String, must be at least 4
336     * @return abbreviated String, {@code null} if null String input
337     * @throws IllegalArgumentException if the width is too small
338     * @since 3.6
339     */
340    public static String abbreviate(final String str, final String abbrevMarker, int offset, final int maxWidth) {
341        if (isNotEmpty(str) && EMPTY.equals(abbrevMarker) && maxWidth > 0) {
342            return substring(str, 0, maxWidth);
343        } else if (isAnyEmpty(str, abbrevMarker)) {
344            return str;
345        }
346        final int abbrevMarkerLength = abbrevMarker.length();
347        final int minAbbrevWidth = abbrevMarkerLength + 1;
348        final int minAbbrevWidthOffset = abbrevMarkerLength + abbrevMarkerLength + 1;
349
350        if (maxWidth < minAbbrevWidth) {
351            throw new IllegalArgumentException(String.format("Minimum abbreviation width is %d", minAbbrevWidth));
352        }
353        final int strLen = str.length();
354        if (strLen <= maxWidth) {
355            return str;
356        }
357        if (offset > strLen) {
358            offset = strLen;
359        }
360        if (strLen - offset < maxWidth - abbrevMarkerLength) {
361            offset = strLen - (maxWidth - abbrevMarkerLength);
362        }
363        if (offset <= abbrevMarkerLength+1) {
364            return str.substring(0, maxWidth - abbrevMarkerLength) + abbrevMarker;
365        }
366        if (maxWidth < minAbbrevWidthOffset) {
367            throw new IllegalArgumentException(String.format("Minimum abbreviation width with offset is %d", minAbbrevWidthOffset));
368        }
369        if (offset + maxWidth - abbrevMarkerLength < strLen) {
370            return abbrevMarker + abbreviate(str.substring(offset), abbrevMarker, maxWidth - abbrevMarkerLength);
371        }
372        return abbrevMarker + str.substring(strLen - (maxWidth - abbrevMarkerLength));
373    }
374
375    /**
376     * <p>Abbreviates a String to the length passed, replacing the middle characters with the supplied
377     * replacement String.</p>
378     *
379     * <p>This abbreviation only occurs if the following criteria is met:</p>
380     * <ul>
381     * <li>Neither the String for abbreviation nor the replacement String are null or empty </li>
382     * <li>The length to truncate to is less than the length of the supplied String</li>
383     * <li>The length to truncate to is greater than 0</li>
384     * <li>The abbreviated String will have enough room for the length supplied replacement String
385     * and the first and last characters of the supplied String for abbreviation</li>
386     * </ul>
387     * <p>Otherwise, the returned String will be the same as the supplied String for abbreviation.
388     * </p>
389     *
390     * <pre>
391     * StringUtils.abbreviateMiddle(null, null, 0)      = null
392     * StringUtils.abbreviateMiddle("abc", null, 0)      = "abc"
393     * StringUtils.abbreviateMiddle("abc", ".", 0)      = "abc"
394     * StringUtils.abbreviateMiddle("abc", ".", 3)      = "abc"
395     * StringUtils.abbreviateMiddle("abcdef", ".", 4)     = "ab.f"
396     * </pre>
397     *
398     * @param str  the String to abbreviate, may be null
399     * @param middle the String to replace the middle characters with, may be null
400     * @param length the length to abbreviate {@code str} to.
401     * @return the abbreviated String if the above criteria is met, or the original String supplied for abbreviation.
402     * @since 2.5
403     */
404    public static String abbreviateMiddle(final String str, final String middle, final int length) {
405        if (isAnyEmpty(str, middle) || length >= str.length() || length < middle.length()+2) {
406            return str;
407        }
408
409        final int targetSting = length-middle.length();
410        final int startOffset = targetSting/2+targetSting%2;
411        final int endOffset = str.length()-targetSting/2;
412
413        return str.substring(0, startOffset) +
414            middle +
415            str.substring(endOffset);
416    }
417
418    /**
419     * Appends the suffix to the end of the string if the string does not
420     * already end with the suffix.
421     *
422     * @param str The string.
423     * @param suffix The suffix to append to the end of the string.
424     * @param ignoreCase Indicates whether the compare should ignore case.
425     * @param suffixes Additional suffixes that are valid terminators (optional).
426     *
427     * @return A new String if suffix was appended, the same string otherwise.
428     */
429    private static String appendIfMissing(final String str, final CharSequence suffix, final boolean ignoreCase, final CharSequence... suffixes) {
430        if (str == null || isEmpty(suffix) || endsWith(str, suffix, ignoreCase)) {
431            return str;
432        }
433        if (ArrayUtils.isNotEmpty(suffixes)) {
434            for (final CharSequence s : suffixes) {
435                if (endsWith(str, s, ignoreCase)) {
436                    return str;
437                }
438            }
439        }
440        return str + suffix.toString();
441    }
442
443    /**
444     * Appends the suffix to the end of the string if the string does not
445     * already end with any of the suffixes.
446     *
447     * <pre>
448     * StringUtils.appendIfMissing(null, null) = null
449     * StringUtils.appendIfMissing("abc", null) = "abc"
450     * StringUtils.appendIfMissing("", "xyz") = "xyz"
451     * StringUtils.appendIfMissing("abc", "xyz") = "abcxyz"
452     * StringUtils.appendIfMissing("abcxyz", "xyz") = "abcxyz"
453     * StringUtils.appendIfMissing("abcXYZ", "xyz") = "abcXYZxyz"
454     * </pre>
455     * <p>With additional suffixes,</p>
456     * <pre>
457     * StringUtils.appendIfMissing(null, null, null) = null
458     * StringUtils.appendIfMissing("abc", null, null) = "abc"
459     * StringUtils.appendIfMissing("", "xyz", null) = "xyz"
460     * StringUtils.appendIfMissing("abc", "xyz", new CharSequence[]{null}) = "abcxyz"
461     * StringUtils.appendIfMissing("abc", "xyz", "") = "abc"
462     * StringUtils.appendIfMissing("abc", "xyz", "mno") = "abcxyz"
463     * StringUtils.appendIfMissing("abcxyz", "xyz", "mno") = "abcxyz"
464     * StringUtils.appendIfMissing("abcmno", "xyz", "mno") = "abcmno"
465     * StringUtils.appendIfMissing("abcXYZ", "xyz", "mno") = "abcXYZxyz"
466     * StringUtils.appendIfMissing("abcMNO", "xyz", "mno") = "abcMNOxyz"
467     * </pre>
468     *
469     * @param str The string.
470     * @param suffix The suffix to append to the end of the string.
471     * @param suffixes Additional suffixes that are valid terminators.
472     *
473     * @return A new String if suffix was appended, the same string otherwise.
474     *
475     * @since 3.2
476     */
477    public static String appendIfMissing(final String str, final CharSequence suffix, final CharSequence... suffixes) {
478        return appendIfMissing(str, suffix, false, suffixes);
479    }
480
481    /**
482     * Appends the suffix to the end of the string if the string does not
483     * already end, case insensitive, with any of the suffixes.
484     *
485     * <pre>
486     * StringUtils.appendIfMissingIgnoreCase(null, null) = null
487     * StringUtils.appendIfMissingIgnoreCase("abc", null) = "abc"
488     * StringUtils.appendIfMissingIgnoreCase("", "xyz") = "xyz"
489     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz") = "abcxyz"
490     * StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz") = "abcxyz"
491     * StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz") = "abcXYZ"
492     * </pre>
493     * <p>With additional suffixes,</p>
494     * <pre>
495     * StringUtils.appendIfMissingIgnoreCase(null, null, null) = null
496     * StringUtils.appendIfMissingIgnoreCase("abc", null, null) = "abc"
497     * StringUtils.appendIfMissingIgnoreCase("", "xyz", null) = "xyz"
498     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", new CharSequence[]{null}) = "abcxyz"
499     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "") = "abc"
500     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "mno") = "abcxyz"
501     * StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz", "mno") = "abcxyz"
502     * StringUtils.appendIfMissingIgnoreCase("abcmno", "xyz", "mno") = "abcmno"
503     * StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz", "mno") = "abcXYZ"
504     * StringUtils.appendIfMissingIgnoreCase("abcMNO", "xyz", "mno") = "abcMNO"
505     * </pre>
506     *
507     * @param str The string.
508     * @param suffix The suffix to append to the end of the string.
509     * @param suffixes Additional suffixes that are valid terminators.
510     *
511     * @return A new String if suffix was appended, the same string otherwise.
512     *
513     * @since 3.2
514     */
515    public static String appendIfMissingIgnoreCase(final String str, final CharSequence suffix, final CharSequence... suffixes) {
516        return appendIfMissing(str, suffix, true, suffixes);
517    }
518
519    /**
520     * <p>Capitalizes a String changing the first character to title case as
521     * per {@link Character#toTitleCase(int)}. No other characters are changed.</p>
522     *
523     * <p>For a word based algorithm, see {@link org.apache.commons.lang3.text.WordUtils#capitalize(String)}.
524     * A {@code null} input String returns {@code null}.</p>
525     *
526     * <pre>
527     * StringUtils.capitalize(null)  = null
528     * StringUtils.capitalize("")    = ""
529     * StringUtils.capitalize("cat") = "Cat"
530     * StringUtils.capitalize("cAt") = "CAt"
531     * StringUtils.capitalize("'cat'") = "'cat'"
532     * </pre>
533     *
534     * @param str the String to capitalize, may be null
535     * @return the capitalized String, {@code null} if null String input
536     * @see org.apache.commons.lang3.text.WordUtils#capitalize(String)
537     * @see #uncapitalize(String)
538     * @since 2.0
539     */
540    public static String capitalize(final String str) {
541        final int strLen = length(str);
542        if (strLen == 0) {
543            return str;
544        }
545
546        final int firstCodepoint = str.codePointAt(0);
547        final int newCodePoint = Character.toTitleCase(firstCodepoint);
548        if (firstCodepoint == newCodePoint) {
549            // already capitalized
550            return str;
551        }
552
553        final int[] newCodePoints = new int[strLen]; // cannot be longer than the char array
554        int outOffset = 0;
555        newCodePoints[outOffset++] = newCodePoint; // copy the first codepoint
556        for (int inOffset = Character.charCount(firstCodepoint); inOffset < strLen; ) {
557            final int codepoint = str.codePointAt(inOffset);
558            newCodePoints[outOffset++] = codepoint; // copy the remaining ones
559            inOffset += Character.charCount(codepoint);
560         }
561        return new String(newCodePoints, 0, outOffset);
562    }
563
564    /**
565     * <p>Centers a String in a larger String of size {@code size}
566     * using the space character (' ').</p>
567     *
568     * <p>If the size is less than the String length, the original String is returned.
569     * A {@code null} String returns {@code null}.
570     * A negative size is treated as zero.</p>
571     *
572     * <p>Equivalent to {@code center(str, size, " ")}.</p>
573     *
574     * <pre>
575     * StringUtils.center(null, *)   = null
576     * StringUtils.center("", 4)     = "    "
577     * StringUtils.center("ab", -1)  = "ab"
578     * StringUtils.center("ab", 4)   = " ab "
579     * StringUtils.center("abcd", 2) = "abcd"
580     * StringUtils.center("a", 4)    = " a  "
581     * </pre>
582     *
583     * @param str  the String to center, may be null
584     * @param size  the int size of new String, negative treated as zero
585     * @return centered String, {@code null} if null String input
586     */
587    public static String center(final String str, final int size) {
588        return center(str, size, ' ');
589    }
590
591    /**
592     * <p>Centers a String in a larger String of size {@code size}.
593     * Uses a supplied character as the value to pad the String with.</p>
594     *
595     * <p>If the size is less than the String length, the String is returned.
596     * A {@code null} String returns {@code null}.
597     * A negative size is treated as zero.</p>
598     *
599     * <pre>
600     * StringUtils.center(null, *, *)     = null
601     * StringUtils.center("", 4, ' ')     = "    "
602     * StringUtils.center("ab", -1, ' ')  = "ab"
603     * StringUtils.center("ab", 4, ' ')   = " ab "
604     * StringUtils.center("abcd", 2, ' ') = "abcd"
605     * StringUtils.center("a", 4, ' ')    = " a  "
606     * StringUtils.center("a", 4, 'y')    = "yayy"
607     * </pre>
608     *
609     * @param str  the String to center, may be null
610     * @param size  the int size of new String, negative treated as zero
611     * @param padChar  the character to pad the new String with
612     * @return centered String, {@code null} if null String input
613     * @since 2.0
614     */
615    public static String center(String str, final int size, final char padChar) {
616        if (str == null || size <= 0) {
617            return str;
618        }
619        final int strLen = str.length();
620        final int pads = size - strLen;
621        if (pads <= 0) {
622            return str;
623        }
624        str = leftPad(str, strLen + pads / 2, padChar);
625        str = rightPad(str, size, padChar);
626        return str;
627    }
628
629    /**
630     * <p>Centers a String in a larger String of size {@code size}.
631     * Uses a supplied String as the value to pad the String with.</p>
632     *
633     * <p>If the size is less than the String length, the String is returned.
634     * A {@code null} String returns {@code null}.
635     * A negative size is treated as zero.</p>
636     *
637     * <pre>
638     * StringUtils.center(null, *, *)     = null
639     * StringUtils.center("", 4, " ")     = "    "
640     * StringUtils.center("ab", -1, " ")  = "ab"
641     * StringUtils.center("ab", 4, " ")   = " ab "
642     * StringUtils.center("abcd", 2, " ") = "abcd"
643     * StringUtils.center("a", 4, " ")    = " a  "
644     * StringUtils.center("a", 4, "yz")   = "yayz"
645     * StringUtils.center("abc", 7, null) = "  abc  "
646     * StringUtils.center("abc", 7, "")   = "  abc  "
647     * </pre>
648     *
649     * @param str  the String to center, may be null
650     * @param size  the int size of new String, negative treated as zero
651     * @param padStr  the String to pad the new String with, must not be null or empty
652     * @return centered String, {@code null} if null String input
653     * @throws IllegalArgumentException if padStr is {@code null} or empty
654     */
655    public static String center(String str, final int size, String padStr) {
656        if (str == null || size <= 0) {
657            return str;
658        }
659        if (isEmpty(padStr)) {
660            padStr = SPACE;
661        }
662        final int strLen = str.length();
663        final int pads = size - strLen;
664        if (pads <= 0) {
665            return str;
666        }
667        str = leftPad(str, strLen + pads / 2, padStr);
668        str = rightPad(str, size, padStr);
669        return str;
670    }
671
672    /**
673     * <p>Removes one newline from end of a String if it's there,
674     * otherwise leave it alone.  A newline is &quot;{@code \n}&quot;,
675     * &quot;{@code \r}&quot;, or &quot;{@code \r\n}&quot;.</p>
676     *
677     * <p>NOTE: This method changed in 2.0.
678     * It now more closely matches Perl chomp.</p>
679     *
680     * <pre>
681     * StringUtils.chomp(null)          = null
682     * StringUtils.chomp("")            = ""
683     * StringUtils.chomp("abc \r")      = "abc "
684     * StringUtils.chomp("abc\n")       = "abc"
685     * StringUtils.chomp("abc\r\n")     = "abc"
686     * StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
687     * StringUtils.chomp("abc\n\r")     = "abc\n"
688     * StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
689     * StringUtils.chomp("\r")          = ""
690     * StringUtils.chomp("\n")          = ""
691     * StringUtils.chomp("\r\n")        = ""
692     * </pre>
693     *
694     * @param str  the String to chomp a newline from, may be null
695     * @return String without newline, {@code null} if null String input
696     */
697    public static String chomp(final String str) {
698        if (isEmpty(str)) {
699            return str;
700        }
701
702        if (str.length() == 1) {
703            final char ch = str.charAt(0);
704            if (ch == CharUtils.CR || ch == CharUtils.LF) {
705                return EMPTY;
706            }
707            return str;
708        }
709
710        int lastIdx = str.length() - 1;
711        final char last = str.charAt(lastIdx);
712
713        if (last == CharUtils.LF) {
714            if (str.charAt(lastIdx - 1) == CharUtils.CR) {
715                lastIdx--;
716            }
717        } else if (last != CharUtils.CR) {
718            lastIdx++;
719        }
720        return str.substring(0, lastIdx);
721    }
722
723    /**
724     * <p>Removes {@code separator} from the end of
725     * {@code str} if it's there, otherwise leave it alone.</p>
726     *
727     * <p>NOTE: This method changed in version 2.0.
728     * It now more closely matches Perl chomp.
729     * For the previous behavior, use {@link #substringBeforeLast(String, String)}.
730     * This method uses {@link String#endsWith(String)}.</p>
731     *
732     * <pre>
733     * StringUtils.chomp(null, *)         = null
734     * StringUtils.chomp("", *)           = ""
735     * StringUtils.chomp("foobar", "bar") = "foo"
736     * StringUtils.chomp("foobar", "baz") = "foobar"
737     * StringUtils.chomp("foo", "foo")    = ""
738     * StringUtils.chomp("foo ", "foo")   = "foo "
739     * StringUtils.chomp(" foo", "foo")   = " "
740     * StringUtils.chomp("foo", "foooo")  = "foo"
741     * StringUtils.chomp("foo", "")       = "foo"
742     * StringUtils.chomp("foo", null)     = "foo"
743     * </pre>
744     *
745     * @param str  the String to chomp from, may be null
746     * @param separator  separator String, may be null
747     * @return String without trailing separator, {@code null} if null String input
748     * @deprecated This feature will be removed in Lang 4.0, use {@link StringUtils#removeEnd(String, String)} instead
749     */
750    @Deprecated
751    public static String chomp(final String str, final String separator) {
752        return removeEnd(str, separator);
753    }
754
755    /**
756     * <p>Remove the last character from a String.</p>
757     *
758     * <p>If the String ends in {@code \r\n}, then remove both
759     * of them.</p>
760     *
761     * <pre>
762     * StringUtils.chop(null)          = null
763     * StringUtils.chop("")            = ""
764     * StringUtils.chop("abc \r")      = "abc "
765     * StringUtils.chop("abc\n")       = "abc"
766     * StringUtils.chop("abc\r\n")     = "abc"
767     * StringUtils.chop("abc")         = "ab"
768     * StringUtils.chop("abc\nabc")    = "abc\nab"
769     * StringUtils.chop("a")           = ""
770     * StringUtils.chop("\r")          = ""
771     * StringUtils.chop("\n")          = ""
772     * StringUtils.chop("\r\n")        = ""
773     * </pre>
774     *
775     * @param str  the String to chop last character from, may be null
776     * @return String without last character, {@code null} if null String input
777     */
778    public static String chop(final String str) {
779        if (str == null) {
780            return null;
781        }
782        final int strLen = str.length();
783        if (strLen < 2) {
784            return EMPTY;
785        }
786        final int lastIdx = strLen - 1;
787        final String ret = str.substring(0, lastIdx);
788        final char last = str.charAt(lastIdx);
789        if (last == CharUtils.LF && ret.charAt(lastIdx - 1) == CharUtils.CR) {
790            return ret.substring(0, lastIdx - 1);
791        }
792        return ret;
793    }
794
795    /**
796     * <p>Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :</p>
797     * <ul>
798     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
799     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
800     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
801     * </ul>
802     *
803     * <p>This is a {@code null} safe version of :</p>
804     * <blockquote><pre>str1.compareTo(str2)</pre></blockquote>
805     *
806     * <p>{@code null} value is considered less than non-{@code null} value.
807     * Two {@code null} references are considered equal.</p>
808     *
809     * <pre>
810     * StringUtils.compare(null, null)   = 0
811     * StringUtils.compare(null , "a")   &lt; 0
812     * StringUtils.compare("a", null)    &gt; 0
813     * StringUtils.compare("abc", "abc") = 0
814     * StringUtils.compare("a", "b")     &lt; 0
815     * StringUtils.compare("b", "a")     &gt; 0
816     * StringUtils.compare("a", "B")     &gt; 0
817     * StringUtils.compare("ab", "abc")  &lt; 0
818     * </pre>
819     *
820     * @see #compare(String, String, boolean)
821     * @see String#compareTo(String)
822     * @param str1  the String to compare from
823     * @param str2  the String to compare to
824     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal or greater than {@code str2}
825     * @since 3.5
826     */
827    public static int compare(final String str1, final String str2) {
828        return compare(str1, str2, true);
829    }
830
831    /**
832     * <p>Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :</p>
833     * <ul>
834     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
835     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
836     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
837     * </ul>
838     *
839     * <p>This is a {@code null} safe version of :</p>
840     * <blockquote><pre>str1.compareTo(str2)</pre></blockquote>
841     *
842     * <p>{@code null} inputs are handled according to the {@code nullIsLess} parameter.
843     * Two {@code null} references are considered equal.</p>
844     *
845     * <pre>
846     * StringUtils.compare(null, null, *)     = 0
847     * StringUtils.compare(null , "a", true)  &lt; 0
848     * StringUtils.compare(null , "a", false) &gt; 0
849     * StringUtils.compare("a", null, true)   &gt; 0
850     * StringUtils.compare("a", null, false)  &lt; 0
851     * StringUtils.compare("abc", "abc", *)   = 0
852     * StringUtils.compare("a", "b", *)       &lt; 0
853     * StringUtils.compare("b", "a", *)       &gt; 0
854     * StringUtils.compare("a", "B", *)       &gt; 0
855     * StringUtils.compare("ab", "abc", *)    &lt; 0
856     * </pre>
857     *
858     * @see String#compareTo(String)
859     * @param str1  the String to compare from
860     * @param str2  the String to compare to
861     * @param nullIsLess  whether consider {@code null} value less than non-{@code null} value
862     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2}
863     * @since 3.5
864     */
865    public static int compare(final String str1, final String str2, final boolean nullIsLess) {
866        if (str1 == str2) { // NOSONARLINT this intentionally uses == to allow for both null
867            return 0;
868        }
869        if (str1 == null) {
870            return nullIsLess ? -1 : 1;
871        }
872        if (str2 == null) {
873            return nullIsLess ? 1 : - 1;
874        }
875        return str1.compareTo(str2);
876    }
877
878    /**
879     * <p>Compare two Strings lexicographically, ignoring case differences,
880     * as per {@link String#compareToIgnoreCase(String)}, returning :</p>
881     * <ul>
882     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
883     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
884     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
885     * </ul>
886     *
887     * <p>This is a {@code null} safe version of :</p>
888     * <blockquote><pre>str1.compareToIgnoreCase(str2)</pre></blockquote>
889     *
890     * <p>{@code null} value is considered less than non-{@code null} value.
891     * Two {@code null} references are considered equal.
892     * Comparison is case insensitive.</p>
893     *
894     * <pre>
895     * StringUtils.compareIgnoreCase(null, null)   = 0
896     * StringUtils.compareIgnoreCase(null , "a")   &lt; 0
897     * StringUtils.compareIgnoreCase("a", null)    &gt; 0
898     * StringUtils.compareIgnoreCase("abc", "abc") = 0
899     * StringUtils.compareIgnoreCase("abc", "ABC") = 0
900     * StringUtils.compareIgnoreCase("a", "b")     &lt; 0
901     * StringUtils.compareIgnoreCase("b", "a")     &gt; 0
902     * StringUtils.compareIgnoreCase("a", "B")     &lt; 0
903     * StringUtils.compareIgnoreCase("A", "b")     &lt; 0
904     * StringUtils.compareIgnoreCase("ab", "ABC")  &lt; 0
905     * </pre>
906     *
907     * @see #compareIgnoreCase(String, String, boolean)
908     * @see String#compareToIgnoreCase(String)
909     * @param str1  the String to compare from
910     * @param str2  the String to compare to
911     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2},
912     *          ignoring case differences.
913     * @since 3.5
914     */
915    public static int compareIgnoreCase(final String str1, final String str2) {
916        return compareIgnoreCase(str1, str2, true);
917    }
918
919    /**
920     * <p>Compare two Strings lexicographically, ignoring case differences,
921     * as per {@link String#compareToIgnoreCase(String)}, returning :</p>
922     * <ul>
923     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
924     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
925     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
926     * </ul>
927     *
928     * <p>This is a {@code null} safe version of :</p>
929     * <blockquote><pre>str1.compareToIgnoreCase(str2)</pre></blockquote>
930     *
931     * <p>{@code null} inputs are handled according to the {@code nullIsLess} parameter.
932     * Two {@code null} references are considered equal.
933     * Comparison is case insensitive.</p>
934     *
935     * <pre>
936     * StringUtils.compareIgnoreCase(null, null, *)     = 0
937     * StringUtils.compareIgnoreCase(null , "a", true)  &lt; 0
938     * StringUtils.compareIgnoreCase(null , "a", false) &gt; 0
939     * StringUtils.compareIgnoreCase("a", null, true)   &gt; 0
940     * StringUtils.compareIgnoreCase("a", null, false)  &lt; 0
941     * StringUtils.compareIgnoreCase("abc", "abc", *)   = 0
942     * StringUtils.compareIgnoreCase("abc", "ABC", *)   = 0
943     * StringUtils.compareIgnoreCase("a", "b", *)       &lt; 0
944     * StringUtils.compareIgnoreCase("b", "a", *)       &gt; 0
945     * StringUtils.compareIgnoreCase("a", "B", *)       &lt; 0
946     * StringUtils.compareIgnoreCase("A", "b", *)       &lt; 0
947     * StringUtils.compareIgnoreCase("ab", "abc", *)    &lt; 0
948     * </pre>
949     *
950     * @see String#compareToIgnoreCase(String)
951     * @param str1  the String to compare from
952     * @param str2  the String to compare to
953     * @param nullIsLess  whether consider {@code null} value less than non-{@code null} value
954     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2},
955     *          ignoring case differences.
956     * @since 3.5
957     */
958    public static int compareIgnoreCase(final String str1, final String str2, final boolean nullIsLess) {
959        if (str1 == str2) { // NOSONARLINT this intentionally uses == to allow for both null
960            return 0;
961        }
962        if (str1 == null) {
963            return nullIsLess ? -1 : 1;
964        }
965        if (str2 == null) {
966            return nullIsLess ? 1 : - 1;
967        }
968        return str1.compareToIgnoreCase(str2);
969    }
970
971    /**
972     * <p>Checks if CharSequence contains a search CharSequence, handling {@code null}.
973     * This method uses {@link String#indexOf(String)} if possible.</p>
974     *
975     * <p>A {@code null} CharSequence will return {@code false}.</p>
976     *
977     * <pre>
978     * StringUtils.contains(null, *)     = false
979     * StringUtils.contains(*, null)     = false
980     * StringUtils.contains("", "")      = true
981     * StringUtils.contains("abc", "")   = true
982     * StringUtils.contains("abc", "a")  = true
983     * StringUtils.contains("abc", "z")  = false
984     * </pre>
985     *
986     * @param seq  the CharSequence to check, may be null
987     * @param searchSeq  the CharSequence to find, may be null
988     * @return true if the CharSequence contains the search CharSequence,
989     *  false if not or {@code null} string input
990     * @since 2.0
991     * @since 3.0 Changed signature from contains(String, String) to contains(CharSequence, CharSequence)
992     */
993    public static boolean contains(final CharSequence seq, final CharSequence searchSeq) {
994        if (seq == null || searchSeq == null) {
995            return false;
996        }
997        return CharSequenceUtils.indexOf(seq, searchSeq, 0) >= 0;
998    }
999
1000    /**
1001     * <p>Checks if CharSequence contains a search character, handling {@code null}.
1002     * This method uses {@link String#indexOf(int)} if possible.</p>
1003     *
1004     * <p>A {@code null} or empty ("") CharSequence will return {@code false}.</p>
1005     *
1006     * <pre>
1007     * StringUtils.contains(null, *)    = false
1008     * StringUtils.contains("", *)      = false
1009     * StringUtils.contains("abc", 'a') = true
1010     * StringUtils.contains("abc", 'z') = false
1011     * </pre>
1012     *
1013     * @param seq  the CharSequence to check, may be null
1014     * @param searchChar  the character to find
1015     * @return true if the CharSequence contains the search character,
1016     *  false if not or {@code null} string input
1017     * @since 2.0
1018     * @since 3.0 Changed signature from contains(String, int) to contains(CharSequence, int)
1019     */
1020    public static boolean contains(final CharSequence seq, final int searchChar) {
1021        if (isEmpty(seq)) {
1022            return false;
1023        }
1024        return CharSequenceUtils.indexOf(seq, searchChar, 0) >= 0;
1025    }
1026
1027    /**
1028     * <p>Checks if the CharSequence contains any character in the given
1029     * set of characters.</p>
1030     *
1031     * <p>A {@code null} CharSequence will return {@code false}.
1032     * A {@code null} or zero length search array will return {@code false}.</p>
1033     *
1034     * <pre>
1035     * StringUtils.containsAny(null, *)                  = false
1036     * StringUtils.containsAny("", *)                    = false
1037     * StringUtils.containsAny(*, null)                  = false
1038     * StringUtils.containsAny(*, [])                    = false
1039     * StringUtils.containsAny("zzabyycdxx", ['z', 'a']) = true
1040     * StringUtils.containsAny("zzabyycdxx", ['b', 'y']) = true
1041     * StringUtils.containsAny("zzabyycdxx", ['z', 'y']) = true
1042     * StringUtils.containsAny("aba", ['z'])             = false
1043     * </pre>
1044     *
1045     * @param cs  the CharSequence to check, may be null
1046     * @param searchChars  the chars to search for, may be null
1047     * @return the {@code true} if any of the chars are found,
1048     * {@code false} if no match or null input
1049     * @since 2.4
1050     * @since 3.0 Changed signature from containsAny(String, char[]) to containsAny(CharSequence, char...)
1051     */
1052    public static boolean containsAny(final CharSequence cs, final char... searchChars) {
1053        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
1054            return false;
1055        }
1056        final int csLength = cs.length();
1057        final int searchLength = searchChars.length;
1058        final int csLast = csLength - 1;
1059        final int searchLast = searchLength - 1;
1060        for (int i = 0; i < csLength; i++) {
1061            final char ch = cs.charAt(i);
1062            for (int j = 0; j < searchLength; j++) {
1063                if (searchChars[j] == ch) {
1064                    if (Character.isHighSurrogate(ch)) {
1065                        if (j == searchLast) {
1066                            // missing low surrogate, fine, like String.indexOf(String)
1067                            return true;
1068                        }
1069                        if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
1070                            return true;
1071                        }
1072                    } else {
1073                        // ch is in the Basic Multilingual Plane
1074                        return true;
1075                    }
1076                }
1077            }
1078        }
1079        return false;
1080    }
1081
1082    /**
1083     * <p>
1084     * Checks if the CharSequence contains any character in the given set of characters.
1085     * </p>
1086     *
1087     * <p>
1088     * A {@code null} CharSequence will return {@code false}. A {@code null} search CharSequence will return
1089     * {@code false}.
1090     * </p>
1091     *
1092     * <pre>
1093     * StringUtils.containsAny(null, *)               = false
1094     * StringUtils.containsAny("", *)                 = false
1095     * StringUtils.containsAny(*, null)               = false
1096     * StringUtils.containsAny(*, "")                 = false
1097     * StringUtils.containsAny("zzabyycdxx", "za")    = true
1098     * StringUtils.containsAny("zzabyycdxx", "by")    = true
1099     * StringUtils.containsAny("zzabyycdxx", "zy")    = true
1100     * StringUtils.containsAny("zzabyycdxx", "\tx")   = true
1101     * StringUtils.containsAny("zzabyycdxx", "$.#yF") = true
1102     * StringUtils.containsAny("aba", "z")            = false
1103     * </pre>
1104     *
1105     * @param cs
1106     *            the CharSequence to check, may be null
1107     * @param searchChars
1108     *            the chars to search for, may be null
1109     * @return the {@code true} if any of the chars are found, {@code false} if no match or null input
1110     * @since 2.4
1111     * @since 3.0 Changed signature from containsAny(String, String) to containsAny(CharSequence, CharSequence)
1112     */
1113    public static boolean containsAny(final CharSequence cs, final CharSequence searchChars) {
1114        if (searchChars == null) {
1115            return false;
1116        }
1117        return containsAny(cs, CharSequenceUtils.toCharArray(searchChars));
1118    }
1119
1120    /**
1121     * <p>
1122     * Checks if the CharSequence contains any of the CharSequences in the given array.
1123     * </p>
1124     *
1125     * <p>
1126     * A {@code null} {@code cs} CharSequence will return {@code false}. A {@code null} or zero length search array will
1127     * return {@code false}.
1128     * </p>
1129     *
1130     * <pre>
1131     * StringUtils.containsAny(null, *)            = false
1132     * StringUtils.containsAny("", *)              = false
1133     * StringUtils.containsAny(*, null)            = false
1134     * StringUtils.containsAny(*, [])              = false
1135     * StringUtils.containsAny("abcd", "ab", null) = true
1136     * StringUtils.containsAny("abcd", "ab", "cd") = true
1137     * StringUtils.containsAny("abc", "d", "abc")  = true
1138     * </pre>
1139     *
1140     *
1141     * @param cs The CharSequence to check, may be null
1142     * @param searchCharSequences The array of CharSequences to search for, may be null. Individual CharSequences may be
1143     *        null as well.
1144     * @return {@code true} if any of the search CharSequences are found, {@code false} otherwise
1145     * @since 3.4
1146     */
1147    public static boolean containsAny(final CharSequence cs, final CharSequence... searchCharSequences) {
1148        return containsAny(StringUtils::contains, cs, searchCharSequences);
1149    }
1150
1151    /**
1152     * <p>
1153     * Checks if the CharSequence contains any of the CharSequences in the given array.
1154     * </p>
1155     *
1156     * <p>
1157     * A {@code null} {@code cs} CharSequence will return {@code false}. A {@code null} or zero length search array will
1158     * return {@code false}.
1159     * </p>
1160     *
1161     * @param cs The CharSequence to check, may be null
1162     * @param searchCharSequences The array of CharSequences to search for, may be null. Individual CharSequences may be
1163     *        null as well.
1164     * @return {@code true} if any of the search CharSequences are found, {@code false} otherwise
1165     * @since 3.12.0
1166     */
1167    private static boolean containsAny(final ToBooleanBiFunction<CharSequence, CharSequence> test,
1168        final CharSequence cs, final CharSequence... searchCharSequences) {
1169        if (isEmpty(cs) || ArrayUtils.isEmpty(searchCharSequences)) {
1170            return false;
1171        }
1172        for (final CharSequence searchCharSequence : searchCharSequences) {
1173            if (test.applyAsBoolean(cs, searchCharSequence)) {
1174                return true;
1175            }
1176        }
1177        return false;
1178    }
1179
1180    /**
1181     * <p>
1182     * Checks if the CharSequence contains any of the CharSequences in the given array, ignoring case.
1183     * </p>
1184     *
1185     * <p>
1186     * A {@code null} {@code cs} CharSequence will return {@code false}. A {@code null} or zero length search array will
1187     * return {@code false}.
1188     * </p>
1189     *
1190     * <pre>
1191     * StringUtils.containsAny(null, *)            = false
1192     * StringUtils.containsAny("", *)              = false
1193     * StringUtils.containsAny(*, null)            = false
1194     * StringUtils.containsAny(*, [])              = false
1195     * StringUtils.containsAny("abcd", "ab", null) = true
1196     * StringUtils.containsAny("abcd", "ab", "cd") = true
1197     * StringUtils.containsAny("abc", "d", "abc")  = true
1198     * StringUtils.containsAny("abc", "D", "ABC")  = true
1199     * StringUtils.containsAny("ABC", "d", "abc")  = true
1200     * </pre>
1201     *
1202     *
1203     * @param cs The CharSequence to check, may be null
1204     * @param searchCharSequences The array of CharSequences to search for, may be null. Individual CharSequences may be
1205     *        null as well.
1206     * @return {@code true} if any of the search CharSequences are found, {@code false} otherwise
1207     * @since 3.12.0
1208     */
1209    public static boolean containsAnyIgnoreCase(final CharSequence cs, final CharSequence... searchCharSequences) {
1210        return containsAny(StringUtils::containsIgnoreCase, cs, searchCharSequences);
1211    }
1212
1213    /**
1214     * <p>Checks if CharSequence contains a search CharSequence irrespective of case,
1215     * handling {@code null}. Case-insensitivity is defined as by
1216     * {@link String#equalsIgnoreCase(String)}.
1217     *
1218     * <p>A {@code null} CharSequence will return {@code false}.</p>
1219     *
1220     * <pre>
1221     * StringUtils.containsIgnoreCase(null, *) = false
1222     * StringUtils.containsIgnoreCase(*, null) = false
1223     * StringUtils.containsIgnoreCase("", "") = true
1224     * StringUtils.containsIgnoreCase("abc", "") = true
1225     * StringUtils.containsIgnoreCase("abc", "a") = true
1226     * StringUtils.containsIgnoreCase("abc", "z") = false
1227     * StringUtils.containsIgnoreCase("abc", "A") = true
1228     * StringUtils.containsIgnoreCase("abc", "Z") = false
1229     * </pre>
1230     *
1231     * @param str  the CharSequence to check, may be null
1232     * @param searchStr  the CharSequence to find, may be null
1233     * @return true if the CharSequence contains the search CharSequence irrespective of
1234     * case or false if not or {@code null} string input
1235     * @since 3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence, CharSequence)
1236     */
1237    public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
1238        if (str == null || searchStr == null) {
1239            return false;
1240        }
1241        final int len = searchStr.length();
1242        final int max = str.length() - len;
1243        for (int i = 0; i <= max; i++) {
1244            if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
1245                return true;
1246            }
1247        }
1248        return false;
1249    }
1250
1251    /**
1252     * <p>Checks that the CharSequence does not contain certain characters.</p>
1253     *
1254     * <p>A {@code null} CharSequence will return {@code true}.
1255     * A {@code null} invalid character array will return {@code true}.
1256     * An empty CharSequence (length()=0) always returns true.</p>
1257     *
1258     * <pre>
1259     * StringUtils.containsNone(null, *)       = true
1260     * StringUtils.containsNone(*, null)       = true
1261     * StringUtils.containsNone("", *)         = true
1262     * StringUtils.containsNone("ab", '')      = true
1263     * StringUtils.containsNone("abab", 'xyz') = true
1264     * StringUtils.containsNone("ab1", 'xyz')  = true
1265     * StringUtils.containsNone("abz", 'xyz')  = false
1266     * </pre>
1267     *
1268     * @param cs  the CharSequence to check, may be null
1269     * @param searchChars  an array of invalid chars, may be null
1270     * @return true if it contains none of the invalid chars, or is null
1271     * @since 2.0
1272     * @since 3.0 Changed signature from containsNone(String, char[]) to containsNone(CharSequence, char...)
1273     */
1274    public static boolean containsNone(final CharSequence cs, final char... searchChars) {
1275        if (cs == null || searchChars == null) {
1276            return true;
1277        }
1278        final int csLen = cs.length();
1279        final int csLast = csLen - 1;
1280        final int searchLen = searchChars.length;
1281        final int searchLast = searchLen - 1;
1282        for (int i = 0; i < csLen; i++) {
1283            final char ch = cs.charAt(i);
1284            for (int j = 0; j < searchLen; j++) {
1285                if (searchChars[j] == ch) {
1286                    if (Character.isHighSurrogate(ch)) {
1287                        if (j == searchLast) {
1288                            // missing low surrogate, fine, like String.indexOf(String)
1289                            return false;
1290                        }
1291                        if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
1292                            return false;
1293                        }
1294                    } else {
1295                        // ch is in the Basic Multilingual Plane
1296                        return false;
1297                    }
1298                }
1299            }
1300        }
1301        return true;
1302    }
1303
1304    /**
1305     * <p>Checks that the CharSequence does not contain certain characters.</p>
1306     *
1307     * <p>A {@code null} CharSequence will return {@code true}.
1308     * A {@code null} invalid character array will return {@code true}.
1309     * An empty String ("") always returns true.</p>
1310     *
1311     * <pre>
1312     * StringUtils.containsNone(null, *)       = true
1313     * StringUtils.containsNone(*, null)       = true
1314     * StringUtils.containsNone("", *)         = true
1315     * StringUtils.containsNone("ab", "")      = true
1316     * StringUtils.containsNone("abab", "xyz") = true
1317     * StringUtils.containsNone("ab1", "xyz")  = true
1318     * StringUtils.containsNone("abz", "xyz")  = false
1319     * </pre>
1320     *
1321     * @param cs  the CharSequence to check, may be null
1322     * @param invalidChars  a String of invalid chars, may be null
1323     * @return true if it contains none of the invalid chars, or is null
1324     * @since 2.0
1325     * @since 3.0 Changed signature from containsNone(String, String) to containsNone(CharSequence, String)
1326     */
1327    public static boolean containsNone(final CharSequence cs, final String invalidChars) {
1328        if (invalidChars == null) {
1329            return true;
1330        }
1331        return containsNone(cs, invalidChars.toCharArray());
1332    }
1333
1334    /**
1335     * <p>Checks if the CharSequence contains only certain characters.</p>
1336     *
1337     * <p>A {@code null} CharSequence will return {@code false}.
1338     * A {@code null} valid character array will return {@code false}.
1339     * An empty CharSequence (length()=0) always returns {@code true}.</p>
1340     *
1341     * <pre>
1342     * StringUtils.containsOnly(null, *)       = false
1343     * StringUtils.containsOnly(*, null)       = false
1344     * StringUtils.containsOnly("", *)         = true
1345     * StringUtils.containsOnly("ab", '')      = false
1346     * StringUtils.containsOnly("abab", 'abc') = true
1347     * StringUtils.containsOnly("ab1", 'abc')  = false
1348     * StringUtils.containsOnly("abz", 'abc')  = false
1349     * </pre>
1350     *
1351     * @param cs  the String to check, may be null
1352     * @param valid  an array of valid chars, may be null
1353     * @return true if it only contains valid chars and is non-null
1354     * @since 3.0 Changed signature from containsOnly(String, char[]) to containsOnly(CharSequence, char...)
1355     */
1356    public static boolean containsOnly(final CharSequence cs, final char... valid) {
1357        // All these pre-checks are to maintain API with an older version
1358        if (valid == null || cs == null) {
1359            return false;
1360        }
1361        if (cs.length() == 0) {
1362            return true;
1363        }
1364        if (valid.length == 0) {
1365            return false;
1366        }
1367        return indexOfAnyBut(cs, valid) == INDEX_NOT_FOUND;
1368    }
1369
1370    /**
1371     * <p>Checks if the CharSequence contains only certain characters.</p>
1372     *
1373     * <p>A {@code null} CharSequence will return {@code false}.
1374     * A {@code null} valid character String will return {@code false}.
1375     * An empty String (length()=0) always returns {@code true}.</p>
1376     *
1377     * <pre>
1378     * StringUtils.containsOnly(null, *)       = false
1379     * StringUtils.containsOnly(*, null)       = false
1380     * StringUtils.containsOnly("", *)         = true
1381     * StringUtils.containsOnly("ab", "")      = false
1382     * StringUtils.containsOnly("abab", "abc") = true
1383     * StringUtils.containsOnly("ab1", "abc")  = false
1384     * StringUtils.containsOnly("abz", "abc")  = false
1385     * </pre>
1386     *
1387     * @param cs  the CharSequence to check, may be null
1388     * @param validChars  a String of valid chars, may be null
1389     * @return true if it only contains valid chars and is non-null
1390     * @since 2.0
1391     * @since 3.0 Changed signature from containsOnly(String, String) to containsOnly(CharSequence, String)
1392     */
1393    public static boolean containsOnly(final CharSequence cs, final String validChars) {
1394        if (cs == null || validChars == null) {
1395            return false;
1396        }
1397        return containsOnly(cs, validChars.toCharArray());
1398    }
1399
1400    /**
1401     * <p>Check whether the given CharSequence contains any whitespace characters.</p>
1402     *
1403     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
1404     *
1405     * @param seq the CharSequence to check (may be {@code null})
1406     * @return {@code true} if the CharSequence is not empty and
1407     * contains at least 1 (breaking) whitespace character
1408     * @since 3.0
1409     */
1410    // From org.springframework.util.StringUtils, under Apache License 2.0
1411    public static boolean containsWhitespace(final CharSequence seq) {
1412        if (isEmpty(seq)) {
1413            return false;
1414        }
1415        final int strLen = seq.length();
1416        for (int i = 0; i < strLen; i++) {
1417            if (Character.isWhitespace(seq.charAt(i))) {
1418                return true;
1419            }
1420        }
1421        return false;
1422    }
1423
1424    private static void convertRemainingAccentCharacters(final StringBuilder decomposed) {
1425        for (int i = 0; i < decomposed.length(); i++) {
1426            if (decomposed.charAt(i) == '\u0141') {
1427                decomposed.setCharAt(i, 'L');
1428            } else if (decomposed.charAt(i) == '\u0142') {
1429                decomposed.setCharAt(i, 'l');
1430            }
1431        }
1432    }
1433
1434    /**
1435     * <p>Counts how many times the char appears in the given string.</p>
1436     *
1437     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
1438     *
1439     * <pre>
1440     * StringUtils.countMatches(null, *)       = 0
1441     * StringUtils.countMatches("", *)         = 0
1442     * StringUtils.countMatches("abba", 0)  = 0
1443     * StringUtils.countMatches("abba", 'a')   = 2
1444     * StringUtils.countMatches("abba", 'b')  = 2
1445     * StringUtils.countMatches("abba", 'x') = 0
1446     * </pre>
1447     *
1448     * @param str  the CharSequence to check, may be null
1449     * @param ch  the char to count
1450     * @return the number of occurrences, 0 if the CharSequence is {@code null}
1451     * @since 3.4
1452     */
1453    public static int countMatches(final CharSequence str, final char ch) {
1454        if (isEmpty(str)) {
1455            return 0;
1456        }
1457        int count = 0;
1458        // We could also call str.toCharArray() for faster look ups but that would generate more garbage.
1459        for (int i = 0; i < str.length(); i++) {
1460            if (ch == str.charAt(i)) {
1461                count++;
1462            }
1463        }
1464        return count;
1465    }
1466
1467    /**
1468     * <p>Counts how many times the substring appears in the larger string.
1469     * Note that the code only counts non-overlapping matches.</p>
1470     *
1471     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
1472     *
1473     * <pre>
1474     * StringUtils.countMatches(null, *)       = 0
1475     * StringUtils.countMatches("", *)         = 0
1476     * StringUtils.countMatches("abba", null)  = 0
1477     * StringUtils.countMatches("abba", "")    = 0
1478     * StringUtils.countMatches("abba", "a")   = 2
1479     * StringUtils.countMatches("abba", "ab")  = 1
1480     * StringUtils.countMatches("abba", "xxx") = 0
1481     * StringUtils.countMatches("ababa", "aba") = 1
1482     * </pre>
1483     *
1484     * @param str  the CharSequence to check, may be null
1485     * @param sub  the substring to count, may be null
1486     * @return the number of occurrences, 0 if either CharSequence is {@code null}
1487     * @since 3.0 Changed signature from countMatches(String, String) to countMatches(CharSequence, CharSequence)
1488     */
1489    public static int countMatches(final CharSequence str, final CharSequence sub) {
1490        if (isEmpty(str) || isEmpty(sub)) {
1491            return 0;
1492        }
1493        int count = 0;
1494        int idx = 0;
1495        while ((idx = CharSequenceUtils.indexOf(str, sub, idx)) != INDEX_NOT_FOUND) {
1496            count++;
1497            idx += sub.length();
1498        }
1499        return count;
1500    }
1501
1502    /**
1503     * <p>Returns either the passed in CharSequence, or if the CharSequence is
1504     * whitespace, empty ("") or {@code null}, the value of {@code defaultStr}.</p>
1505     *
1506     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
1507     *
1508     * <pre>
1509     * StringUtils.defaultIfBlank(null, "NULL")  = "NULL"
1510     * StringUtils.defaultIfBlank("", "NULL")    = "NULL"
1511     * StringUtils.defaultIfBlank(" ", "NULL")   = "NULL"
1512     * StringUtils.defaultIfBlank("bat", "NULL") = "bat"
1513     * StringUtils.defaultIfBlank("", null)      = null
1514     * </pre>
1515     * @param <T> the specific kind of CharSequence
1516     * @param str the CharSequence to check, may be null
1517     * @param defaultStr  the default CharSequence to return
1518     *  if the input is whitespace, empty ("") or {@code null}, may be null
1519     * @return the passed in CharSequence, or the default
1520     * @see StringUtils#defaultString(String, String)
1521     */
1522    public static <T extends CharSequence> T defaultIfBlank(final T str, final T defaultStr) {
1523        return isBlank(str) ? defaultStr : str;
1524    }
1525
1526    /**
1527     * <p>Returns either the passed in CharSequence, or if the CharSequence is
1528     * empty or {@code null}, the value of {@code defaultStr}.</p>
1529     *
1530     * <pre>
1531     * StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
1532     * StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
1533     * StringUtils.defaultIfEmpty(" ", "NULL")   = " "
1534     * StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
1535     * StringUtils.defaultIfEmpty("", null)      = null
1536     * </pre>
1537     * @param <T> the specific kind of CharSequence
1538     * @param str  the CharSequence to check, may be null
1539     * @param defaultStr  the default CharSequence to return
1540     *  if the input is empty ("") or {@code null}, may be null
1541     * @return the passed in CharSequence, or the default
1542     * @see StringUtils#defaultString(String, String)
1543     */
1544    public static <T extends CharSequence> T defaultIfEmpty(final T str, final T defaultStr) {
1545        return isEmpty(str) ? defaultStr : str;
1546    }
1547
1548    /**
1549     * <p>Returns either the passed in String,
1550     * or if the String is {@code null}, an empty String ("").</p>
1551     *
1552     * <pre>
1553     * StringUtils.defaultString(null)  = ""
1554     * StringUtils.defaultString("")    = ""
1555     * StringUtils.defaultString("bat") = "bat"
1556     * </pre>
1557     *
1558     * @see ObjectUtils#toString(Object)
1559     * @see String#valueOf(Object)
1560     * @param str  the String to check, may be null
1561     * @return the passed in String, or the empty String if it
1562     *  was {@code null}
1563     */
1564    public static String defaultString(final String str) {
1565        return defaultString(str, EMPTY);
1566    }
1567
1568    /**
1569     * <p>Returns either the passed in String, or if the String is
1570     * {@code null}, the value of {@code defaultStr}.</p>
1571     *
1572     * <pre>
1573     * StringUtils.defaultString(null, "NULL")  = "NULL"
1574     * StringUtils.defaultString("", "NULL")    = ""
1575     * StringUtils.defaultString("bat", "NULL") = "bat"
1576     * </pre>
1577     *
1578     * @see ObjectUtils#toString(Object,String)
1579     * @see String#valueOf(Object)
1580     * @param str  the String to check, may be null
1581     * @param defaultStr  the default String to return
1582     *  if the input is {@code null}, may be null
1583     * @return the passed in String, or the default if it was {@code null}
1584     */
1585    public static String defaultString(final String str, final String defaultStr) {
1586        return str == null ? defaultStr : str;
1587    }
1588
1589    /**
1590     * <p>Deletes all whitespaces from a String as defined by
1591     * {@link Character#isWhitespace(char)}.</p>
1592     *
1593     * <pre>
1594     * StringUtils.deleteWhitespace(null)         = null
1595     * StringUtils.deleteWhitespace("")           = ""
1596     * StringUtils.deleteWhitespace("abc")        = "abc"
1597     * StringUtils.deleteWhitespace("   ab  c  ") = "abc"
1598     * </pre>
1599     *
1600     * @param str  the String to delete whitespace from, may be null
1601     * @return the String without whitespaces, {@code null} if null String input
1602     */
1603    public static String deleteWhitespace(final String str) {
1604        if (isEmpty(str)) {
1605            return str;
1606        }
1607        final int sz = str.length();
1608        final char[] chs = new char[sz];
1609        int count = 0;
1610        for (int i = 0; i < sz; i++) {
1611            if (!Character.isWhitespace(str.charAt(i))) {
1612                chs[count++] = str.charAt(i);
1613            }
1614        }
1615        if (count == sz) {
1616            return str;
1617        }
1618        if (count == 0) {
1619            return EMPTY;
1620        }
1621        return new String(chs, 0, count);
1622    }
1623
1624    /**
1625     * <p>Compares two Strings, and returns the portion where they differ.
1626     * More precisely, return the remainder of the second String,
1627     * starting from where it's different from the first. This means that
1628     * the difference between "abc" and "ab" is the empty String and not "c". </p>
1629     *
1630     * <p>For example,
1631     * {@code difference("i am a machine", "i am a robot") -> "robot"}.</p>
1632     *
1633     * <pre>
1634     * StringUtils.difference(null, null) = null
1635     * StringUtils.difference("", "") = ""
1636     * StringUtils.difference("", "abc") = "abc"
1637     * StringUtils.difference("abc", "") = ""
1638     * StringUtils.difference("abc", "abc") = ""
1639     * StringUtils.difference("abc", "ab") = ""
1640     * StringUtils.difference("ab", "abxyz") = "xyz"
1641     * StringUtils.difference("abcde", "abxyz") = "xyz"
1642     * StringUtils.difference("abcde", "xyz") = "xyz"
1643     * </pre>
1644     *
1645     * @param str1  the first String, may be null
1646     * @param str2  the second String, may be null
1647     * @return the portion of str2 where it differs from str1; returns the
1648     * empty String if they are equal
1649     * @see #indexOfDifference(CharSequence,CharSequence)
1650     * @since 2.0
1651     */
1652    public static String difference(final String str1, final String str2) {
1653        if (str1 == null) {
1654            return str2;
1655        }
1656        if (str2 == null) {
1657            return str1;
1658        }
1659        final int at = indexOfDifference(str1, str2);
1660        if (at == INDEX_NOT_FOUND) {
1661            return EMPTY;
1662        }
1663        return str2.substring(at);
1664    }
1665
1666    /**
1667     * <p>Check if a CharSequence ends with a specified suffix.</p>
1668     *
1669     * <p>{@code null}s are handled without exceptions. Two {@code null}
1670     * references are considered to be equal. The comparison is case sensitive.</p>
1671     *
1672     * <pre>
1673     * StringUtils.endsWith(null, null)      = true
1674     * StringUtils.endsWith(null, "def")     = false
1675     * StringUtils.endsWith("abcdef", null)  = false
1676     * StringUtils.endsWith("abcdef", "def") = true
1677     * StringUtils.endsWith("ABCDEF", "def") = false
1678     * StringUtils.endsWith("ABCDEF", "cde") = false
1679     * StringUtils.endsWith("ABCDEF", "")    = true
1680     * </pre>
1681     *
1682     * @see java.lang.String#endsWith(String)
1683     * @param str  the CharSequence to check, may be null
1684     * @param suffix the suffix to find, may be null
1685     * @return {@code true} if the CharSequence ends with the suffix, case sensitive, or
1686     *  both {@code null}
1687     * @since 2.4
1688     * @since 3.0 Changed signature from endsWith(String, String) to endsWith(CharSequence, CharSequence)
1689     */
1690    public static boolean endsWith(final CharSequence str, final CharSequence suffix) {
1691        return endsWith(str, suffix, false);
1692    }
1693
1694    /**
1695     * <p>Check if a CharSequence ends with a specified suffix (optionally case insensitive).</p>
1696     *
1697     * @see java.lang.String#endsWith(String)
1698     * @param str  the CharSequence to check, may be null
1699     * @param suffix the suffix to find, may be null
1700     * @param ignoreCase indicates whether the compare should ignore case
1701     *  (case insensitive) or not.
1702     * @return {@code true} if the CharSequence starts with the prefix or
1703     *  both {@code null}
1704     */
1705    private static boolean endsWith(final CharSequence str, final CharSequence suffix, final boolean ignoreCase) {
1706        if (str == null || suffix == null) {
1707            return str == suffix;
1708        }
1709        if (suffix.length() > str.length()) {
1710            return false;
1711        }
1712        final int strOffset = str.length() - suffix.length();
1713        return CharSequenceUtils.regionMatches(str, ignoreCase, strOffset, suffix, 0, suffix.length());
1714    }
1715
1716    /**
1717     * <p>Check if a CharSequence ends with any of the provided case-sensitive suffixes.</p>
1718     *
1719     * <pre>
1720     * StringUtils.endsWithAny(null, null)      = false
1721     * StringUtils.endsWithAny(null, new String[] {"abc"})  = false
1722     * StringUtils.endsWithAny("abcxyz", null)     = false
1723     * StringUtils.endsWithAny("abcxyz", new String[] {""}) = true
1724     * StringUtils.endsWithAny("abcxyz", new String[] {"xyz"}) = true
1725     * StringUtils.endsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
1726     * StringUtils.endsWithAny("abcXYZ", "def", "XYZ") = true
1727     * StringUtils.endsWithAny("abcXYZ", "def", "xyz") = false
1728     * </pre>
1729     *
1730     * @param sequence  the CharSequence to check, may be null
1731     * @param searchStrings the case-sensitive CharSequences to find, may be empty or contain {@code null}
1732     * @see StringUtils#endsWith(CharSequence, CharSequence)
1733     * @return {@code true} if the input {@code sequence} is {@code null} AND no {@code searchStrings} are provided, or
1734     *   the input {@code sequence} ends in any of the provided case-sensitive {@code searchStrings}.
1735     * @since 3.0
1736     */
1737    public static boolean endsWithAny(final CharSequence sequence, final CharSequence... searchStrings) {
1738        if (isEmpty(sequence) || ArrayUtils.isEmpty(searchStrings)) {
1739            return false;
1740        }
1741        for (final CharSequence searchString : searchStrings) {
1742            if (endsWith(sequence, searchString)) {
1743                return true;
1744            }
1745        }
1746        return false;
1747    }
1748
1749    /**
1750     * <p>Case insensitive check if a CharSequence ends with a specified suffix.</p>
1751     *
1752     * <p>{@code null}s are handled without exceptions. Two {@code null}
1753     * references are considered to be equal. The comparison is case insensitive.</p>
1754     *
1755     * <pre>
1756     * StringUtils.endsWithIgnoreCase(null, null)      = true
1757     * StringUtils.endsWithIgnoreCase(null, "def")     = false
1758     * StringUtils.endsWithIgnoreCase("abcdef", null)  = false
1759     * StringUtils.endsWithIgnoreCase("abcdef", "def") = true
1760     * StringUtils.endsWithIgnoreCase("ABCDEF", "def") = true
1761     * StringUtils.endsWithIgnoreCase("ABCDEF", "cde") = false
1762     * </pre>
1763     *
1764     * @see java.lang.String#endsWith(String)
1765     * @param str  the CharSequence to check, may be null
1766     * @param suffix the suffix to find, may be null
1767     * @return {@code true} if the CharSequence ends with the suffix, case insensitive, or
1768     *  both {@code null}
1769     * @since 2.4
1770     * @since 3.0 Changed signature from endsWithIgnoreCase(String, String) to endsWithIgnoreCase(CharSequence, CharSequence)
1771     */
1772    public static boolean endsWithIgnoreCase(final CharSequence str, final CharSequence suffix) {
1773        return endsWith(str, suffix, true);
1774    }
1775
1776    /**
1777     * <p>Compares two CharSequences, returning {@code true} if they represent
1778     * equal sequences of characters.</p>
1779     *
1780     * <p>{@code null}s are handled without exceptions. Two {@code null}
1781     * references are considered to be equal. The comparison is <strong>case sensitive</strong>.</p>
1782     *
1783     * <pre>
1784     * StringUtils.equals(null, null)   = true
1785     * StringUtils.equals(null, "abc")  = false
1786     * StringUtils.equals("abc", null)  = false
1787     * StringUtils.equals("abc", "abc") = true
1788     * StringUtils.equals("abc", "ABC") = false
1789     * </pre>
1790     *
1791     * @param cs1  the first CharSequence, may be {@code null}
1792     * @param cs2  the second CharSequence, may be {@code null}
1793     * @return {@code true} if the CharSequences are equal (case-sensitive), or both {@code null}
1794     * @since 3.0 Changed signature from equals(String, String) to equals(CharSequence, CharSequence)
1795     * @see Object#equals(Object)
1796     * @see #equalsIgnoreCase(CharSequence, CharSequence)
1797     */
1798    public static boolean equals(final CharSequence cs1, final CharSequence cs2) {
1799        if (cs1 == cs2) {
1800            return true;
1801        }
1802        if (cs1 == null || cs2 == null) {
1803            return false;
1804        }
1805        if (cs1.length() != cs2.length()) {
1806            return false;
1807        }
1808        if (cs1 instanceof String && cs2 instanceof String) {
1809            return cs1.equals(cs2);
1810        }
1811        // Step-wise comparison
1812        final int length = cs1.length();
1813        for (int i = 0; i < length; i++) {
1814            if (cs1.charAt(i) != cs2.charAt(i)) {
1815                return false;
1816            }
1817        }
1818        return true;
1819    }
1820
1821    /**
1822     * <p>Compares given {@code string} to a CharSequences vararg of {@code searchStrings},
1823     * returning {@code true} if the {@code string} is equal to any of the {@code searchStrings}.</p>
1824     *
1825     * <pre>
1826     * StringUtils.equalsAny(null, (CharSequence[]) null) = false
1827     * StringUtils.equalsAny(null, null, null)    = true
1828     * StringUtils.equalsAny(null, "abc", "def")  = false
1829     * StringUtils.equalsAny("abc", null, "def")  = false
1830     * StringUtils.equalsAny("abc", "abc", "def") = true
1831     * StringUtils.equalsAny("abc", "ABC", "DEF") = false
1832     * </pre>
1833     *
1834     * @param string to compare, may be {@code null}.
1835     * @param searchStrings a vararg of strings, may be {@code null}.
1836     * @return {@code true} if the string is equal (case-sensitive) to any other element of {@code searchStrings};
1837     * {@code false} if {@code searchStrings} is null or contains no matches.
1838     * @since 3.5
1839     */
1840    public static boolean equalsAny(final CharSequence string, final CharSequence... searchStrings) {
1841        if (ArrayUtils.isNotEmpty(searchStrings)) {
1842            for (final CharSequence next : searchStrings) {
1843                if (equals(string, next)) {
1844                    return true;
1845                }
1846            }
1847        }
1848        return false;
1849    }
1850
1851    /**
1852     * <p>Compares given {@code string} to a CharSequences vararg of {@code searchStrings},
1853     * returning {@code true} if the {@code string} is equal to any of the {@code searchStrings}, ignoring case.</p>
1854     *
1855     * <pre>
1856     * StringUtils.equalsAnyIgnoreCase(null, (CharSequence[]) null) = false
1857     * StringUtils.equalsAnyIgnoreCase(null, null, null)    = true
1858     * StringUtils.equalsAnyIgnoreCase(null, "abc", "def")  = false
1859     * StringUtils.equalsAnyIgnoreCase("abc", null, "def")  = false
1860     * StringUtils.equalsAnyIgnoreCase("abc", "abc", "def") = true
1861     * StringUtils.equalsAnyIgnoreCase("abc", "ABC", "DEF") = true
1862     * </pre>
1863     *
1864     * @param string to compare, may be {@code null}.
1865     * @param searchStrings a vararg of strings, may be {@code null}.
1866     * @return {@code true} if the string is equal (case-insensitive) to any other element of {@code searchStrings};
1867     * {@code false} if {@code searchStrings} is null or contains no matches.
1868     * @since 3.5
1869     */
1870    public static boolean equalsAnyIgnoreCase(final CharSequence string, final CharSequence...searchStrings) {
1871        if (ArrayUtils.isNotEmpty(searchStrings)) {
1872            for (final CharSequence next : searchStrings) {
1873                if (equalsIgnoreCase(string, next)) {
1874                    return true;
1875                }
1876            }
1877        }
1878        return false;
1879    }
1880
1881    /**
1882     * <p>Compares two CharSequences, returning {@code true} if they represent
1883     * equal sequences of characters, ignoring case.</p>
1884     *
1885     * <p>{@code null}s are handled without exceptions. Two {@code null}
1886     * references are considered equal. The comparison is <strong>case insensitive</strong>.</p>
1887     *
1888     * <pre>
1889     * StringUtils.equalsIgnoreCase(null, null)   = true
1890     * StringUtils.equalsIgnoreCase(null, "abc")  = false
1891     * StringUtils.equalsIgnoreCase("abc", null)  = false
1892     * StringUtils.equalsIgnoreCase("abc", "abc") = true
1893     * StringUtils.equalsIgnoreCase("abc", "ABC") = true
1894     * </pre>
1895     *
1896     * @param cs1  the first CharSequence, may be {@code null}
1897     * @param cs2  the second CharSequence, may be {@code null}
1898     * @return {@code true} if the CharSequences are equal (case-insensitive), or both {@code null}
1899     * @since 3.0 Changed signature from equalsIgnoreCase(String, String) to equalsIgnoreCase(CharSequence, CharSequence)
1900     * @see #equals(CharSequence, CharSequence)
1901     */
1902    public static boolean equalsIgnoreCase(final CharSequence cs1, final CharSequence cs2) {
1903        if (cs1 == cs2) {
1904            return true;
1905        }
1906        if (cs1 == null || cs2 == null) {
1907            return false;
1908        }
1909        if (cs1.length() != cs2.length()) {
1910            return false;
1911        }
1912        return CharSequenceUtils.regionMatches(cs1, true, 0, cs2, 0, cs1.length());
1913    }
1914
1915    /**
1916     * <p>Returns the first value in the array which is not empty (""),
1917     * {@code null} or whitespace only.</p>
1918     *
1919     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
1920     *
1921     * <p>If all values are blank or the array is {@code null}
1922     * or empty then {@code null} is returned.</p>
1923     *
1924     * <pre>
1925     * StringUtils.firstNonBlank(null, null, null)     = null
1926     * StringUtils.firstNonBlank(null, "", " ")        = null
1927     * StringUtils.firstNonBlank("abc")                = "abc"
1928     * StringUtils.firstNonBlank(null, "xyz")          = "xyz"
1929     * StringUtils.firstNonBlank(null, "", " ", "xyz") = "xyz"
1930     * StringUtils.firstNonBlank(null, "xyz", "abc")   = "xyz"
1931     * StringUtils.firstNonBlank()                     = null
1932     * </pre>
1933     *
1934     * @param <T> the specific kind of CharSequence
1935     * @param values  the values to test, may be {@code null} or empty
1936     * @return the first value from {@code values} which is not blank,
1937     *  or {@code null} if there are no non-blank values
1938     * @since 3.8
1939     */
1940    @SafeVarargs
1941    public static <T extends CharSequence> T firstNonBlank(final T... values) {
1942        if (values != null) {
1943            for (final T val : values) {
1944                if (isNotBlank(val)) {
1945                    return val;
1946                }
1947            }
1948        }
1949        return null;
1950    }
1951
1952    /**
1953     * <p>Returns the first value in the array which is not empty.</p>
1954     *
1955     * <p>If all values are empty or the array is {@code null}
1956     * or empty then {@code null} is returned.</p>
1957     *
1958     * <pre>
1959     * StringUtils.firstNonEmpty(null, null, null)   = null
1960     * StringUtils.firstNonEmpty(null, null, "")     = null
1961     * StringUtils.firstNonEmpty(null, "", " ")      = " "
1962     * StringUtils.firstNonEmpty("abc")              = "abc"
1963     * StringUtils.firstNonEmpty(null, "xyz")        = "xyz"
1964     * StringUtils.firstNonEmpty("", "xyz")          = "xyz"
1965     * StringUtils.firstNonEmpty(null, "xyz", "abc") = "xyz"
1966     * StringUtils.firstNonEmpty()                   = null
1967     * </pre>
1968     *
1969     * @param <T> the specific kind of CharSequence
1970     * @param values  the values to test, may be {@code null} or empty
1971     * @return the first value from {@code values} which is not empty,
1972     *  or {@code null} if there are no non-empty values
1973     * @since 3.8
1974     */
1975    @SafeVarargs
1976    public static <T extends CharSequence> T firstNonEmpty(final T... values) {
1977        if (values != null) {
1978            for (final T val : values) {
1979                if (isNotEmpty(val)) {
1980                    return val;
1981                }
1982            }
1983        }
1984        return null;
1985    }
1986
1987    /**
1988     * Calls {@link String#getBytes(Charset)} in a null-safe manner.
1989     *
1990     * @param string input string
1991     * @param charset The {@link Charset} to encode the {@code String}. If null, then use the default Charset.
1992     * @return The empty byte[] if {@code string} is null, the result of {@link String#getBytes(Charset)} otherwise.
1993     * @see String#getBytes(Charset)
1994     * @since 3.10
1995     */
1996    public static byte[] getBytes(final String string, final Charset charset) {
1997        return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharset(charset));
1998    }
1999
2000    /**
2001     * Calls {@link String#getBytes(String)} in a null-safe manner.
2002     *
2003     * @param string input string
2004     * @param charset The {@link Charset} name to encode the {@code String}. If null, then use the default Charset.
2005     * @return The empty byte[] if {@code string} is null, the result of {@link String#getBytes(String)} otherwise.
2006     * @throws UnsupportedEncodingException Thrown when the named charset is not supported.
2007     * @see String#getBytes(String)
2008     * @since 3.10
2009     */
2010    public static byte[] getBytes(final String string, final String charset) throws UnsupportedEncodingException {
2011        return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharsetName(charset));
2012    }
2013
2014    /**
2015     * <p>Compares all Strings in an array and returns the initial sequence of
2016     * characters that is common to all of them.</p>
2017     *
2018     * <p>For example,
2019     * {@code getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) -&gt; "i am a "}</p>
2020     *
2021     * <pre>
2022     * StringUtils.getCommonPrefix(null) = ""
2023     * StringUtils.getCommonPrefix(new String[] {}) = ""
2024     * StringUtils.getCommonPrefix(new String[] {"abc"}) = "abc"
2025     * StringUtils.getCommonPrefix(new String[] {null, null}) = ""
2026     * StringUtils.getCommonPrefix(new String[] {"", ""}) = ""
2027     * StringUtils.getCommonPrefix(new String[] {"", null}) = ""
2028     * StringUtils.getCommonPrefix(new String[] {"abc", null, null}) = ""
2029     * StringUtils.getCommonPrefix(new String[] {null, null, "abc"}) = ""
2030     * StringUtils.getCommonPrefix(new String[] {"", "abc"}) = ""
2031     * StringUtils.getCommonPrefix(new String[] {"abc", ""}) = ""
2032     * StringUtils.getCommonPrefix(new String[] {"abc", "abc"}) = "abc"
2033     * StringUtils.getCommonPrefix(new String[] {"abc", "a"}) = "a"
2034     * StringUtils.getCommonPrefix(new String[] {"ab", "abxyz"}) = "ab"
2035     * StringUtils.getCommonPrefix(new String[] {"abcde", "abxyz"}) = "ab"
2036     * StringUtils.getCommonPrefix(new String[] {"abcde", "xyz"}) = ""
2037     * StringUtils.getCommonPrefix(new String[] {"xyz", "abcde"}) = ""
2038     * StringUtils.getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) = "i am a "
2039     * </pre>
2040     *
2041     * @param strs  array of String objects, entries may be null
2042     * @return the initial sequence of characters that are common to all Strings
2043     * in the array; empty String if the array is null, the elements are all null
2044     * or if there is no common prefix.
2045     * @since 2.4
2046     */
2047    public static String getCommonPrefix(final String... strs) {
2048        if (ArrayUtils.isEmpty(strs)) {
2049            return EMPTY;
2050        }
2051        final int smallestIndexOfDiff = indexOfDifference(strs);
2052        if (smallestIndexOfDiff == INDEX_NOT_FOUND) {
2053            // all strings were identical
2054            if (strs[0] == null) {
2055                return EMPTY;
2056            }
2057            return strs[0];
2058        } else if (smallestIndexOfDiff == 0) {
2059            // there were no common initial characters
2060            return EMPTY;
2061        } else {
2062            // we found a common initial character sequence
2063            return strs[0].substring(0, smallestIndexOfDiff);
2064        }
2065    }
2066
2067    /**
2068     * <p>Checks if a String {@code str} contains Unicode digits,
2069     * if yes then concatenate all the digits in {@code str} and return it as a String.</p>
2070     *
2071     * <p>An empty ("") String will be returned if no digits found in {@code str}.</p>
2072     *
2073     * <pre>
2074     * StringUtils.getDigits(null)  = null
2075     * StringUtils.getDigits("")    = ""
2076     * StringUtils.getDigits("abc") = ""
2077     * StringUtils.getDigits("1000$") = "1000"
2078     * StringUtils.getDigits("1123~45") = "112345"
2079     * StringUtils.getDigits("(541) 754-3010") = "5417543010"
2080     * StringUtils.getDigits("\u0967\u0968\u0969") = "\u0967\u0968\u0969"
2081     * </pre>
2082     *
2083     * @param str the String to extract digits from, may be null
2084     * @return String with only digits,
2085     *           or an empty ("") String if no digits found,
2086     *           or {@code null} String if {@code str} is null
2087     * @since 3.6
2088     */
2089    public static String getDigits(final String str) {
2090        if (isEmpty(str)) {
2091            return str;
2092        }
2093        final int sz = str.length();
2094        final StringBuilder strDigits = new StringBuilder(sz);
2095        for (int i = 0; i < sz; i++) {
2096            final char tempChar = str.charAt(i);
2097            if (Character.isDigit(tempChar)) {
2098                strDigits.append(tempChar);
2099            }
2100        }
2101        return strDigits.toString();
2102    }
2103
2104    /**
2105     * <p>Find the Fuzzy Distance which indicates the similarity score between two Strings.</p>
2106     *
2107     * <p>This string matching algorithm is similar to the algorithms of editors such as Sublime Text,
2108     * TextMate, Atom and others. One point is given for every matched character. Subsequent
2109     * matches yield two bonus points. A higher score indicates a higher similarity.</p>
2110     *
2111     * <pre>
2112     * StringUtils.getFuzzyDistance(null, null, null)                                    = IllegalArgumentException
2113     * StringUtils.getFuzzyDistance("", "", Locale.ENGLISH)                              = 0
2114     * StringUtils.getFuzzyDistance("Workshop", "b", Locale.ENGLISH)                     = 0
2115     * StringUtils.getFuzzyDistance("Room", "o", Locale.ENGLISH)                         = 1
2116     * StringUtils.getFuzzyDistance("Workshop", "w", Locale.ENGLISH)                     = 1
2117     * StringUtils.getFuzzyDistance("Workshop", "ws", Locale.ENGLISH)                    = 2
2118     * StringUtils.getFuzzyDistance("Workshop", "wo", Locale.ENGLISH)                    = 4
2119     * StringUtils.getFuzzyDistance("Apache Software Foundation", "asf", Locale.ENGLISH) = 3
2120     * </pre>
2121     *
2122     * @param term a full term that should be matched against, must not be null
2123     * @param query the query that will be matched against a term, must not be null
2124     * @param locale This string matching logic is case insensitive. A locale is necessary to normalize
2125     *  both Strings to lower case.
2126     * @return result score
2127     * @throws IllegalArgumentException if either String input {@code null} or Locale input {@code null}
2128     * @since 3.4
2129     * @deprecated as of 3.6, use commons-text
2130     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/FuzzyScore.html">
2131     * FuzzyScore</a> instead
2132     */
2133    @Deprecated
2134    public static int getFuzzyDistance(final CharSequence term, final CharSequence query, final Locale locale) {
2135        if (term == null || query == null) {
2136            throw new IllegalArgumentException("Strings must not be null");
2137        } else if (locale == null) {
2138            throw new IllegalArgumentException("Locale must not be null");
2139        }
2140
2141        // fuzzy logic is case insensitive. We normalize the Strings to lower
2142        // case right from the start. Turning characters to lower case
2143        // via Character.toLowerCase(char) is unfortunately insufficient
2144        // as it does not accept a locale.
2145        final String termLowerCase = term.toString().toLowerCase(locale);
2146        final String queryLowerCase = query.toString().toLowerCase(locale);
2147
2148        // the resulting score
2149        int score = 0;
2150
2151        // the position in the term which will be scanned next for potential
2152        // query character matches
2153        int termIndex = 0;
2154
2155        // index of the previously matched character in the term
2156        int previousMatchingCharacterIndex = Integer.MIN_VALUE;
2157
2158        for (int queryIndex = 0; queryIndex < queryLowerCase.length(); queryIndex++) {
2159            final char queryChar = queryLowerCase.charAt(queryIndex);
2160
2161            boolean termCharacterMatchFound = false;
2162            for (; termIndex < termLowerCase.length() && !termCharacterMatchFound; termIndex++) {
2163                final char termChar = termLowerCase.charAt(termIndex);
2164
2165                if (queryChar == termChar) {
2166                    // simple character matches result in one point
2167                    score++;
2168
2169                    // subsequent character matches further improve
2170                    // the score.
2171                    if (previousMatchingCharacterIndex + 1 == termIndex) {
2172                        score += 2;
2173                    }
2174
2175                    previousMatchingCharacterIndex = termIndex;
2176
2177                    // we can leave the nested loop. Every character in the
2178                    // query can match at most one character in the term.
2179                    termCharacterMatchFound = true;
2180                }
2181            }
2182        }
2183
2184        return score;
2185    }
2186
2187    /**
2188     * <p>Returns either the passed in CharSequence, or if the CharSequence is
2189     * whitespace, empty ("") or {@code null}, the value supplied by {@code defaultStrSupplier}.</p>
2190     *
2191     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
2192     *
2193     * <p>Caller responsible for thread-safety and exception handling of default value supplier</p>
2194     *
2195     * <pre>
2196     * {@code
2197     * StringUtils.getIfBlank(null, () -> "NULL")   = "NULL"
2198     * StringUtils.getIfBlank("", () -> "NULL")     = "NULL"
2199     * StringUtils.getIfBlank(" ", () -> "NULL")    = "NULL"
2200     * StringUtils.getIfBlank("bat", () -> "NULL")  = "bat"
2201     * StringUtils.getIfBlank("", () -> null)       = null
2202     * StringUtils.getIfBlank("", null)             = null
2203     * }</pre>
2204     * @param <T> the specific kind of CharSequence
2205     * @param str the CharSequence to check, may be null
2206     * @param defaultSupplier the supplier of default CharSequence to return
2207     *  if the input is whitespace, empty ("") or {@code null}, may be null
2208     * @return the passed in CharSequence, or the default
2209     * @see StringUtils#defaultString(String, String)
2210     * @since 3.10
2211     */
2212    public static <T extends CharSequence> T getIfBlank(final T str, final Supplier<T> defaultSupplier) {
2213        return isBlank(str) ? defaultSupplier == null ? null : defaultSupplier.get() : str;
2214    }
2215
2216    /**
2217     * <p>Returns either the passed in CharSequence, or if the CharSequence is
2218     * empty or {@code null}, the value supplied by {@code defaultStrSupplier}.</p>
2219     *
2220     * <p>Caller responsible for thread-safety and exception handling of default value supplier</p>
2221     *
2222     * <pre>
2223     * {@code
2224     * StringUtils.getIfEmpty(null, () -> "NULL")    = "NULL"
2225     * StringUtils.getIfEmpty("", () -> "NULL")      = "NULL"
2226     * StringUtils.getIfEmpty(" ", () -> "NULL")     = " "
2227     * StringUtils.getIfEmpty("bat", () -> "NULL")   = "bat"
2228     * StringUtils.getIfEmpty("", () -> null)        = null
2229     * StringUtils.getIfEmpty("", null)              = null
2230     * }
2231     * </pre>
2232     * @param <T> the specific kind of CharSequence
2233     * @param str  the CharSequence to check, may be null
2234     * @param defaultSupplier  the supplier of default CharSequence to return
2235     *  if the input is empty ("") or {@code null}, may be null
2236     * @return the passed in CharSequence, or the default
2237     * @see StringUtils#defaultString(String, String)
2238     * @since 3.10
2239     */
2240    public static <T extends CharSequence> T getIfEmpty(final T str, final Supplier<T> defaultSupplier) {
2241        return isEmpty(str) ? defaultSupplier == null ? null : defaultSupplier.get() : str;
2242    }
2243
2244    /**
2245     * <p>Find the Jaro Winkler Distance which indicates the similarity score between two Strings.</p>
2246     *
2247     * <p>The Jaro measure is the weighted sum of percentage of matched characters from each file and transposed characters.
2248     * Winkler increased this measure for matching initial characters.</p>
2249     *
2250     * <p>This implementation is based on the Jaro Winkler similarity algorithm
2251     * from <a href="http://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance">http://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance</a>.</p>
2252     *
2253     * <pre>
2254     * StringUtils.getJaroWinklerDistance(null, null)          = IllegalArgumentException
2255     * StringUtils.getJaroWinklerDistance("", "")              = 0.0
2256     * StringUtils.getJaroWinklerDistance("", "a")             = 0.0
2257     * StringUtils.getJaroWinklerDistance("aaapppp", "")       = 0.0
2258     * StringUtils.getJaroWinklerDistance("frog", "fog")       = 0.93
2259     * StringUtils.getJaroWinklerDistance("fly", "ant")        = 0.0
2260     * StringUtils.getJaroWinklerDistance("elephant", "hippo") = 0.44
2261     * StringUtils.getJaroWinklerDistance("hippo", "elephant") = 0.44
2262     * StringUtils.getJaroWinklerDistance("hippo", "zzzzzzzz") = 0.0
2263     * StringUtils.getJaroWinklerDistance("hello", "hallo")    = 0.88
2264     * StringUtils.getJaroWinklerDistance("ABC Corporation", "ABC Corp") = 0.93
2265     * StringUtils.getJaroWinklerDistance("D N H Enterprises Inc", "D &amp; H Enterprises, Inc.") = 0.95
2266     * StringUtils.getJaroWinklerDistance("My Gym Children's Fitness Center", "My Gym. Childrens Fitness") = 0.92
2267     * StringUtils.getJaroWinklerDistance("PENNSYLVANIA", "PENNCISYLVNIA") = 0.88
2268     * </pre>
2269     *
2270     * @param first the first String, must not be null
2271     * @param second the second String, must not be null
2272     * @return result distance
2273     * @throws IllegalArgumentException if either String input {@code null}
2274     * @since 3.3
2275     * @deprecated as of 3.6, use commons-text
2276     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/JaroWinklerDistance.html">
2277     * JaroWinklerDistance</a> instead
2278     */
2279    @Deprecated
2280    public static double getJaroWinklerDistance(final CharSequence first, final CharSequence second) {
2281        final double DEFAULT_SCALING_FACTOR = 0.1;
2282
2283        if (first == null || second == null) {
2284            throw new IllegalArgumentException("Strings must not be null");
2285        }
2286
2287        final int[] mtp = matches(first, second);
2288        final double m = mtp[0];
2289        if (m == 0) {
2290            return 0D;
2291        }
2292        final double j = (m / first.length() + m / second.length() + (m - mtp[1]) / m) / 3;
2293        final double jw = j < 0.7D ? j : j + Math.min(DEFAULT_SCALING_FACTOR, 1D / mtp[3]) * mtp[2] * (1D - j);
2294        return Math.round(jw * 100.0D) / 100.0D;
2295    }
2296
2297    /**
2298     * <p>Find the Levenshtein distance between two Strings.</p>
2299     *
2300     * <p>This is the number of changes needed to change one String into
2301     * another, where each change is a single character modification (deletion,
2302     * insertion or substitution).</p>
2303     *
2304     * <p>The implementation uses a single-dimensional array of length s.length() + 1. See
2305     * <a href="http://blog.softwx.net/2014/12/optimizing-levenshtein-algorithm-in-c.html">
2306     * http://blog.softwx.net/2014/12/optimizing-levenshtein-algorithm-in-c.html</a> for details.</p>
2307     *
2308     * <pre>
2309     * StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
2310     * StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
2311     * StringUtils.getLevenshteinDistance("", "")              = 0
2312     * StringUtils.getLevenshteinDistance("", "a")             = 1
2313     * StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
2314     * StringUtils.getLevenshteinDistance("frog", "fog")       = 1
2315     * StringUtils.getLevenshteinDistance("fly", "ant")        = 3
2316     * StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
2317     * StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
2318     * StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
2319     * StringUtils.getLevenshteinDistance("hello", "hallo")    = 1
2320     * </pre>
2321     *
2322     * @param s  the first String, must not be null
2323     * @param t  the second String, must not be null
2324     * @return result distance
2325     * @throws IllegalArgumentException if either String input {@code null}
2326     * @since 3.0 Changed signature from getLevenshteinDistance(String, String) to
2327     * getLevenshteinDistance(CharSequence, CharSequence)
2328     * @deprecated as of 3.6, use commons-text
2329     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/LevenshteinDistance.html">
2330     * LevenshteinDistance</a> instead
2331     */
2332    @Deprecated
2333    public static int getLevenshteinDistance(CharSequence s, CharSequence t) {
2334        if (s == null || t == null) {
2335            throw new IllegalArgumentException("Strings must not be null");
2336        }
2337
2338        int n = s.length();
2339        int m = t.length();
2340
2341        if (n == 0) {
2342            return m;
2343        } else if (m == 0) {
2344            return n;
2345        }
2346
2347        if (n > m) {
2348            // swap the input strings to consume less memory
2349            final CharSequence tmp = s;
2350            s = t;
2351            t = tmp;
2352            n = m;
2353            m = t.length();
2354        }
2355
2356        final int[] p = new int[n + 1];
2357        // indexes into strings s and t
2358        int i; // iterates through s
2359        int j; // iterates through t
2360        int upper_left;
2361        int upper;
2362
2363        char t_j; // jth character of t
2364        int cost;
2365
2366        for (i = 0; i <= n; i++) {
2367            p[i] = i;
2368        }
2369
2370        for (j = 1; j <= m; j++) {
2371            upper_left = p[0];
2372            t_j = t.charAt(j - 1);
2373            p[0] = j;
2374
2375            for (i = 1; i <= n; i++) {
2376                upper = p[i];
2377                cost = s.charAt(i - 1) == t_j ? 0 : 1;
2378                // minimum of cell to the left+1, to the top+1, diagonally left and up +cost
2379                p[i] = Math.min(Math.min(p[i - 1] + 1, p[i] + 1), upper_left + cost);
2380                upper_left = upper;
2381            }
2382        }
2383
2384        return p[n];
2385    }
2386
2387    /**
2388     * <p>Find the Levenshtein distance between two Strings if it's less than or equal to a given
2389     * threshold.</p>
2390     *
2391     * <p>This is the number of changes needed to change one String into
2392     * another, where each change is a single character modification (deletion,
2393     * insertion or substitution).</p>
2394     *
2395     * <p>This implementation follows from Algorithms on Strings, Trees and Sequences by Dan Gusfield
2396     * and Chas Emerick's implementation of the Levenshtein distance algorithm from
2397     * <a href="http://www.merriampark.com/ld.htm">http://www.merriampark.com/ld.htm</a></p>
2398     *
2399     * <pre>
2400     * StringUtils.getLevenshteinDistance(null, *, *)             = IllegalArgumentException
2401     * StringUtils.getLevenshteinDistance(*, null, *)             = IllegalArgumentException
2402     * StringUtils.getLevenshteinDistance(*, *, -1)               = IllegalArgumentException
2403     * StringUtils.getLevenshteinDistance("", "", 0)              = 0
2404     * StringUtils.getLevenshteinDistance("aaapppp", "", 8)       = 7
2405     * StringUtils.getLevenshteinDistance("aaapppp", "", 7)       = 7
2406     * StringUtils.getLevenshteinDistance("aaapppp", "", 6))      = -1
2407     * StringUtils.getLevenshteinDistance("elephant", "hippo", 7) = 7
2408     * StringUtils.getLevenshteinDistance("elephant", "hippo", 6) = -1
2409     * StringUtils.getLevenshteinDistance("hippo", "elephant", 7) = 7
2410     * StringUtils.getLevenshteinDistance("hippo", "elephant", 6) = -1
2411     * </pre>
2412     *
2413     * @param s  the first String, must not be null
2414     * @param t  the second String, must not be null
2415     * @param threshold the target threshold, must not be negative
2416     * @return result distance, or {@code -1} if the distance would be greater than the threshold
2417     * @throws IllegalArgumentException if either String input {@code null} or negative threshold
2418     * @deprecated as of 3.6, use commons-text
2419     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/LevenshteinDistance.html">
2420     * LevenshteinDistance</a> instead
2421     */
2422    @Deprecated
2423    public static int getLevenshteinDistance(CharSequence s, CharSequence t, final int threshold) {
2424        if (s == null || t == null) {
2425            throw new IllegalArgumentException("Strings must not be null");
2426        }
2427        if (threshold < 0) {
2428            throw new IllegalArgumentException("Threshold must not be negative");
2429        }
2430
2431        /*
2432        This implementation only computes the distance if it's less than or equal to the
2433        threshold value, returning -1 if it's greater.  The advantage is performance: unbounded
2434        distance is O(nm), but a bound of k allows us to reduce it to O(km) time by only
2435        computing a diagonal stripe of width 2k + 1 of the cost table.
2436        It is also possible to use this to compute the unbounded Levenshtein distance by starting
2437        the threshold at 1 and doubling each time until the distance is found; this is O(dm), where
2438        d is the distance.
2439
2440        One subtlety comes from needing to ignore entries on the border of our stripe
2441        eg.
2442        p[] = |#|#|#|*
2443        d[] =  *|#|#|#|
2444        We must ignore the entry to the left of the leftmost member
2445        We must ignore the entry above the rightmost member
2446
2447        Another subtlety comes from our stripe running off the matrix if the strings aren't
2448        of the same size.  Since string s is always swapped to be the shorter of the two,
2449        the stripe will always run off to the upper right instead of the lower left of the matrix.
2450
2451        As a concrete example, suppose s is of length 5, t is of length 7, and our threshold is 1.
2452        In this case we're going to walk a stripe of length 3.  The matrix would look like so:
2453
2454           1 2 3 4 5
2455        1 |#|#| | | |
2456        2 |#|#|#| | |
2457        3 | |#|#|#| |
2458        4 | | |#|#|#|
2459        5 | | | |#|#|
2460        6 | | | | |#|
2461        7 | | | | | |
2462
2463        Note how the stripe leads off the table as there is no possible way to turn a string of length 5
2464        into one of length 7 in edit distance of 1.
2465
2466        Additionally, this implementation decreases memory usage by using two
2467        single-dimensional arrays and swapping them back and forth instead of allocating
2468        an entire n by m matrix.  This requires a few minor changes, such as immediately returning
2469        when it's detected that the stripe has run off the matrix and initially filling the arrays with
2470        large values so that entries we don't compute are ignored.
2471
2472        See Algorithms on Strings, Trees and Sequences by Dan Gusfield for some discussion.
2473         */
2474
2475        int n = s.length(); // length of s
2476        int m = t.length(); // length of t
2477
2478        // if one string is empty, the edit distance is necessarily the length of the other
2479        if (n == 0) {
2480            return m <= threshold ? m : -1;
2481        } else if (m == 0) {
2482            return n <= threshold ? n : -1;
2483        } else if (Math.abs(n - m) > threshold) {
2484            // no need to calculate the distance if the length difference is greater than the threshold
2485            return -1;
2486        }
2487
2488        if (n > m) {
2489            // swap the two strings to consume less memory
2490            final CharSequence tmp = s;
2491            s = t;
2492            t = tmp;
2493            n = m;
2494            m = t.length();
2495        }
2496
2497        int[] p = new int[n + 1]; // 'previous' cost array, horizontally
2498        int[] d = new int[n + 1]; // cost array, horizontally
2499        int[] _d; // placeholder to assist in swapping p and d
2500
2501        // fill in starting table values
2502        final int boundary = Math.min(n, threshold) + 1;
2503        for (int i = 0; i < boundary; i++) {
2504            p[i] = i;
2505        }
2506        // these fills ensure that the value above the rightmost entry of our
2507        // stripe will be ignored in following loop iterations
2508        Arrays.fill(p, boundary, p.length, Integer.MAX_VALUE);
2509        Arrays.fill(d, Integer.MAX_VALUE);
2510
2511        // iterates through t
2512        for (int j = 1; j <= m; j++) {
2513            final char t_j = t.charAt(j - 1); // jth character of t
2514            d[0] = j;
2515
2516            // compute stripe indices, constrain to array size
2517            final int min = Math.max(1, j - threshold);
2518            final int max = j > Integer.MAX_VALUE - threshold ? n : Math.min(n, j + threshold);
2519
2520            // the stripe may lead off of the table if s and t are of different sizes
2521            if (min > max) {
2522                return -1;
2523            }
2524
2525            // ignore entry left of leftmost
2526            if (min > 1) {
2527                d[min - 1] = Integer.MAX_VALUE;
2528            }
2529
2530            // iterates through [min, max] in s
2531            for (int i = min; i <= max; i++) {
2532                if (s.charAt(i - 1) == t_j) {
2533                    // diagonally left and up
2534                    d[i] = p[i - 1];
2535                } else {
2536                    // 1 + minimum of cell to the left, to the top, diagonally left and up
2537                    d[i] = 1 + Math.min(Math.min(d[i - 1], p[i]), p[i - 1]);
2538                }
2539            }
2540
2541            // copy current distance counts to 'previous row' distance counts
2542            _d = p;
2543            p = d;
2544            d = _d;
2545        }
2546
2547        // if p[n] is greater than the threshold, there's no guarantee on it being the correct
2548        // distance
2549        if (p[n] <= threshold) {
2550            return p[n];
2551        }
2552        return -1;
2553    }
2554
2555    /**
2556     * <p>Finds the first index within a CharSequence, handling {@code null}.
2557     * This method uses {@link String#indexOf(String, int)} if possible.</p>
2558     *
2559     * <p>A {@code null} CharSequence will return {@code -1}.</p>
2560     *
2561     * <pre>
2562     * StringUtils.indexOf(null, *)          = -1
2563     * StringUtils.indexOf(*, null)          = -1
2564     * StringUtils.indexOf("", "")           = 0
2565     * StringUtils.indexOf("", *)            = -1 (except when * = "")
2566     * StringUtils.indexOf("aabaabaa", "a")  = 0
2567     * StringUtils.indexOf("aabaabaa", "b")  = 2
2568     * StringUtils.indexOf("aabaabaa", "ab") = 1
2569     * StringUtils.indexOf("aabaabaa", "")   = 0
2570     * </pre>
2571     *
2572     * @param seq  the CharSequence to check, may be null
2573     * @param searchSeq  the CharSequence to find, may be null
2574     * @return the first index of the search CharSequence,
2575     *  -1 if no match or {@code null} string input
2576     * @since 2.0
2577     * @since 3.0 Changed signature from indexOf(String, String) to indexOf(CharSequence, CharSequence)
2578     */
2579    public static int indexOf(final CharSequence seq, final CharSequence searchSeq) {
2580        if (seq == null || searchSeq == null) {
2581            return INDEX_NOT_FOUND;
2582        }
2583        return CharSequenceUtils.indexOf(seq, searchSeq, 0);
2584    }
2585
2586    /**
2587     * <p>Finds the first index within a CharSequence, handling {@code null}.
2588     * This method uses {@link String#indexOf(String, int)} if possible.</p>
2589     *
2590     * <p>A {@code null} CharSequence will return {@code -1}.
2591     * A negative start position is treated as zero.
2592     * An empty ("") search CharSequence always matches.
2593     * A start position greater than the string length only matches
2594     * an empty search CharSequence.</p>
2595     *
2596     * <pre>
2597     * StringUtils.indexOf(null, *, *)          = -1
2598     * StringUtils.indexOf(*, null, *)          = -1
2599     * StringUtils.indexOf("", "", 0)           = 0
2600     * StringUtils.indexOf("", *, 0)            = -1 (except when * = "")
2601     * StringUtils.indexOf("aabaabaa", "a", 0)  = 0
2602     * StringUtils.indexOf("aabaabaa", "b", 0)  = 2
2603     * StringUtils.indexOf("aabaabaa", "ab", 0) = 1
2604     * StringUtils.indexOf("aabaabaa", "b", 3)  = 5
2605     * StringUtils.indexOf("aabaabaa", "b", 9)  = -1
2606     * StringUtils.indexOf("aabaabaa", "b", -1) = 2
2607     * StringUtils.indexOf("aabaabaa", "", 2)   = 2
2608     * StringUtils.indexOf("abc", "", 9)        = 3
2609     * </pre>
2610     *
2611     * @param seq  the CharSequence to check, may be null
2612     * @param searchSeq  the CharSequence to find, may be null
2613     * @param startPos  the start position, negative treated as zero
2614     * @return the first index of the search CharSequence (always &ge; startPos),
2615     *  -1 if no match or {@code null} string input
2616     * @since 2.0
2617     * @since 3.0 Changed signature from indexOf(String, String, int) to indexOf(CharSequence, CharSequence, int)
2618     */
2619    public static int indexOf(final CharSequence seq, final CharSequence searchSeq, final int startPos) {
2620        if (seq == null || searchSeq == null) {
2621            return INDEX_NOT_FOUND;
2622        }
2623        return CharSequenceUtils.indexOf(seq, searchSeq, startPos);
2624    }
2625
2626    /**
2627     * Returns the index within {@code seq} of the first occurrence of
2628     * the specified character. If a character with value
2629     * {@code searchChar} occurs in the character sequence represented by
2630     * {@code seq} {@code CharSequence} object, then the index (in Unicode
2631     * code units) of the first such occurrence is returned. For
2632     * values of {@code searchChar} in the range from 0 to 0xFFFF
2633     * (inclusive), this is the smallest value <i>k</i> such that:
2634     * <blockquote><pre>
2635     * this.charAt(<i>k</i>) == searchChar
2636     * </pre></blockquote>
2637     * is true. For other values of {@code searchChar}, it is the
2638     * smallest value <i>k</i> such that:
2639     * <blockquote><pre>
2640     * this.codePointAt(<i>k</i>) == searchChar
2641     * </pre></blockquote>
2642     * is true. In either case, if no such character occurs in {@code seq},
2643     * then {@code INDEX_NOT_FOUND (-1)} is returned.
2644     *
2645     * <p>Furthermore, a {@code null} or empty ("") CharSequence will
2646     * return {@code INDEX_NOT_FOUND (-1)}.</p>
2647     *
2648     * <pre>
2649     * StringUtils.indexOf(null, *)         = -1
2650     * StringUtils.indexOf("", *)           = -1
2651     * StringUtils.indexOf("aabaabaa", 'a') = 0
2652     * StringUtils.indexOf("aabaabaa", 'b') = 2
2653     * </pre>
2654     *
2655     * @param seq  the CharSequence to check, may be null
2656     * @param searchChar  the character to find
2657     * @return the first index of the search character,
2658     *  -1 if no match or {@code null} string input
2659     * @since 2.0
2660     * @since 3.0 Changed signature from indexOf(String, int) to indexOf(CharSequence, int)
2661     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@code String}
2662     */
2663    public static int indexOf(final CharSequence seq, final int searchChar) {
2664        if (isEmpty(seq)) {
2665            return INDEX_NOT_FOUND;
2666        }
2667        return CharSequenceUtils.indexOf(seq, searchChar, 0);
2668    }
2669
2670    /**
2671     *
2672     * Returns the index within {@code seq} of the first occurrence of the
2673     * specified character, starting the search at the specified index.
2674     * <p>
2675     * If a character with value {@code searchChar} occurs in the
2676     * character sequence represented by the {@code seq} {@code CharSequence}
2677     * object at an index no smaller than {@code startPos}, then
2678     * the index of the first such occurrence is returned. For values
2679     * of {@code searchChar} in the range from 0 to 0xFFFF (inclusive),
2680     * this is the smallest value <i>k</i> such that:
2681     * <blockquote><pre>
2682     * (this.charAt(<i>k</i>) == searchChar) &amp;&amp; (<i>k</i> &gt;= startPos)
2683     * </pre></blockquote>
2684     * is true. For other values of {@code searchChar}, it is the
2685     * smallest value <i>k</i> such that:
2686     * <blockquote><pre>
2687     * (this.codePointAt(<i>k</i>) == searchChar) &amp;&amp; (<i>k</i> &gt;= startPos)
2688     * </pre></blockquote>
2689     * is true. In either case, if no such character occurs in {@code seq}
2690     * at or after position {@code startPos}, then
2691     * {@code -1} is returned.
2692     *
2693     * <p>
2694     * There is no restriction on the value of {@code startPos}. If it
2695     * is negative, it has the same effect as if it were zero: this entire
2696     * string may be searched. If it is greater than the length of this
2697     * string, it has the same effect as if it were equal to the length of
2698     * this string: {@code (INDEX_NOT_FOUND) -1} is returned. Furthermore, a
2699     * {@code null} or empty ("") CharSequence will
2700     * return {@code (INDEX_NOT_FOUND) -1}.
2701     *
2702     * <p>All indices are specified in {@code char} values
2703     * (Unicode code units).
2704     *
2705     * <pre>
2706     * StringUtils.indexOf(null, *, *)          = -1
2707     * StringUtils.indexOf("", *, *)            = -1
2708     * StringUtils.indexOf("aabaabaa", 'b', 0)  = 2
2709     * StringUtils.indexOf("aabaabaa", 'b', 3)  = 5
2710     * StringUtils.indexOf("aabaabaa", 'b', 9)  = -1
2711     * StringUtils.indexOf("aabaabaa", 'b', -1) = 2
2712     * </pre>
2713     *
2714     * @param seq  the CharSequence to check, may be null
2715     * @param searchChar  the character to find
2716     * @param startPos  the start position, negative treated as zero
2717     * @return the first index of the search character (always &ge; startPos),
2718     *  -1 if no match or {@code null} string input
2719     * @since 2.0
2720     * @since 3.0 Changed signature from indexOf(String, int, int) to indexOf(CharSequence, int, int)
2721     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@code String}
2722     */
2723    public static int indexOf(final CharSequence seq, final int searchChar, final int startPos) {
2724        if (isEmpty(seq)) {
2725            return INDEX_NOT_FOUND;
2726        }
2727        return CharSequenceUtils.indexOf(seq, searchChar, startPos);
2728    }
2729
2730    /**
2731     * <p>Search a CharSequence to find the first index of any
2732     * character in the given set of characters.</p>
2733     *
2734     * <p>A {@code null} String will return {@code -1}.
2735     * A {@code null} or zero length search array will return {@code -1}.</p>
2736     *
2737     * <pre>
2738     * StringUtils.indexOfAny(null, *)                  = -1
2739     * StringUtils.indexOfAny("", *)                    = -1
2740     * StringUtils.indexOfAny(*, null)                  = -1
2741     * StringUtils.indexOfAny(*, [])                    = -1
2742     * StringUtils.indexOfAny("zzabyycdxx", ['z', 'a']) = 0
2743     * StringUtils.indexOfAny("zzabyycdxx", ['b', 'y']) = 3
2744     * StringUtils.indexOfAny("aba", ['z'])             = -1
2745     * </pre>
2746     *
2747     * @param cs  the CharSequence to check, may be null
2748     * @param searchChars  the chars to search for, may be null
2749     * @return the index of any of the chars, -1 if no match or null input
2750     * @since 2.0
2751     * @since 3.0 Changed signature from indexOfAny(String, char[]) to indexOfAny(CharSequence, char...)
2752     */
2753    public static int indexOfAny(final CharSequence cs, final char... searchChars) {
2754        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
2755            return INDEX_NOT_FOUND;
2756        }
2757        final int csLen = cs.length();
2758        final int csLast = csLen - 1;
2759        final int searchLen = searchChars.length;
2760        final int searchLast = searchLen - 1;
2761        for (int i = 0; i < csLen; i++) {
2762            final char ch = cs.charAt(i);
2763            for (int j = 0; j < searchLen; j++) {
2764                if (searchChars[j] == ch) {
2765                    if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
2766                        // ch is a supplementary character
2767                        if (searchChars[j + 1] == cs.charAt(i + 1)) {
2768                            return i;
2769                        }
2770                    } else {
2771                        return i;
2772                    }
2773                }
2774            }
2775        }
2776        return INDEX_NOT_FOUND;
2777    }
2778
2779    /**
2780     * <p>Find the first index of any of a set of potential substrings.</p>
2781     *
2782     * <p>A {@code null} CharSequence will return {@code -1}.
2783     * A {@code null} or zero length search array will return {@code -1}.
2784     * A {@code null} search array entry will be ignored, but a search
2785     * array containing "" will return {@code 0} if {@code str} is not
2786     * null. This method uses {@link String#indexOf(String)} if possible.</p>
2787     *
2788     * <pre>
2789     * StringUtils.indexOfAny(null, *)                      = -1
2790     * StringUtils.indexOfAny(*, null)                      = -1
2791     * StringUtils.indexOfAny(*, [])                        = -1
2792     * StringUtils.indexOfAny("zzabyycdxx", ["ab", "cd"])   = 2
2793     * StringUtils.indexOfAny("zzabyycdxx", ["cd", "ab"])   = 2
2794     * StringUtils.indexOfAny("zzabyycdxx", ["mn", "op"])   = -1
2795     * StringUtils.indexOfAny("zzabyycdxx", ["zab", "aby"]) = 1
2796     * StringUtils.indexOfAny("zzabyycdxx", [""])           = 0
2797     * StringUtils.indexOfAny("", [""])                     = 0
2798     * StringUtils.indexOfAny("", ["a"])                    = -1
2799     * </pre>
2800     *
2801     * @param str  the CharSequence to check, may be null
2802     * @param searchStrs  the CharSequences to search for, may be null
2803     * @return the first index of any of the searchStrs in str, -1 if no match
2804     * @since 3.0 Changed signature from indexOfAny(String, String[]) to indexOfAny(CharSequence, CharSequence...)
2805     */
2806    public static int indexOfAny(final CharSequence str, final CharSequence... searchStrs) {
2807        if (str == null || searchStrs == null) {
2808            return INDEX_NOT_FOUND;
2809        }
2810
2811        // String's can't have a MAX_VALUEth index.
2812        int ret = Integer.MAX_VALUE;
2813
2814        int tmp = 0;
2815        for (final CharSequence search : searchStrs) {
2816            if (search == null) {
2817                continue;
2818            }
2819            tmp = CharSequenceUtils.indexOf(str, search, 0);
2820            if (tmp == INDEX_NOT_FOUND) {
2821                continue;
2822            }
2823
2824            if (tmp < ret) {
2825                ret = tmp;
2826            }
2827        }
2828
2829        return ret == Integer.MAX_VALUE ? INDEX_NOT_FOUND : ret;
2830    }
2831
2832    /**
2833     * <p>Search a CharSequence to find the first index of any
2834     * character in the given set of characters.</p>
2835     *
2836     * <p>A {@code null} String will return {@code -1}.
2837     * A {@code null} search string will return {@code -1}.</p>
2838     *
2839     * <pre>
2840     * StringUtils.indexOfAny(null, *)            = -1
2841     * StringUtils.indexOfAny("", *)              = -1
2842     * StringUtils.indexOfAny(*, null)            = -1
2843     * StringUtils.indexOfAny(*, "")              = -1
2844     * StringUtils.indexOfAny("zzabyycdxx", "za") = 0
2845     * StringUtils.indexOfAny("zzabyycdxx", "by") = 3
2846     * StringUtils.indexOfAny("aba", "z")         = -1
2847     * </pre>
2848     *
2849     * @param cs  the CharSequence to check, may be null
2850     * @param searchChars  the chars to search for, may be null
2851     * @return the index of any of the chars, -1 if no match or null input
2852     * @since 2.0
2853     * @since 3.0 Changed signature from indexOfAny(String, String) to indexOfAny(CharSequence, String)
2854     */
2855    public static int indexOfAny(final CharSequence cs, final String searchChars) {
2856        if (isEmpty(cs) || isEmpty(searchChars)) {
2857            return INDEX_NOT_FOUND;
2858        }
2859        return indexOfAny(cs, searchChars.toCharArray());
2860    }
2861
2862    /**
2863     * <p>Searches a CharSequence to find the first index of any
2864     * character not in the given set of characters.</p>
2865     *
2866     * <p>A {@code null} CharSequence will return {@code -1}.
2867     * A {@code null} or zero length search array will return {@code -1}.</p>
2868     *
2869     * <pre>
2870     * StringUtils.indexOfAnyBut(null, *)                              = -1
2871     * StringUtils.indexOfAnyBut("", *)                                = -1
2872     * StringUtils.indexOfAnyBut(*, null)                              = -1
2873     * StringUtils.indexOfAnyBut(*, [])                                = -1
2874     * StringUtils.indexOfAnyBut("zzabyycdxx", new char[] {'z', 'a'} ) = 3
2875     * StringUtils.indexOfAnyBut("aba", new char[] {'z'} )             = 0
2876     * StringUtils.indexOfAnyBut("aba", new char[] {'a', 'b'} )        = -1
2877
2878     * </pre>
2879     *
2880     * @param cs  the CharSequence to check, may be null
2881     * @param searchChars  the chars to search for, may be null
2882     * @return the index of any of the chars, -1 if no match or null input
2883     * @since 2.0
2884     * @since 3.0 Changed signature from indexOfAnyBut(String, char[]) to indexOfAnyBut(CharSequence, char...)
2885     */
2886    public static int indexOfAnyBut(final CharSequence cs, final char... searchChars) {
2887        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
2888            return INDEX_NOT_FOUND;
2889        }
2890        final int csLen = cs.length();
2891        final int csLast = csLen - 1;
2892        final int searchLen = searchChars.length;
2893        final int searchLast = searchLen - 1;
2894        outer:
2895        for (int i = 0; i < csLen; i++) {
2896            final char ch = cs.charAt(i);
2897            for (int j = 0; j < searchLen; j++) {
2898                if (searchChars[j] == ch) {
2899                    if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
2900                        if (searchChars[j + 1] == cs.charAt(i + 1)) {
2901                            continue outer;
2902                        }
2903                    } else {
2904                        continue outer;
2905                    }
2906                }
2907            }
2908            return i;
2909        }
2910        return INDEX_NOT_FOUND;
2911    }
2912
2913    /**
2914     * <p>Search a CharSequence to find the first index of any
2915     * character not in the given set of characters.</p>
2916     *
2917     * <p>A {@code null} CharSequence will return {@code -1}.
2918     * A {@code null} or empty search string will return {@code -1}.</p>
2919     *
2920     * <pre>
2921     * StringUtils.indexOfAnyBut(null, *)            = -1
2922     * StringUtils.indexOfAnyBut("", *)              = -1
2923     * StringUtils.indexOfAnyBut(*, null)            = -1
2924     * StringUtils.indexOfAnyBut(*, "")              = -1
2925     * StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
2926     * StringUtils.indexOfAnyBut("zzabyycdxx", "")   = -1
2927     * StringUtils.indexOfAnyBut("aba", "ab")        = -1
2928     * </pre>
2929     *
2930     * @param seq  the CharSequence to check, may be null
2931     * @param searchChars  the chars to search for, may be null
2932     * @return the index of any of the chars, -1 if no match or null input
2933     * @since 2.0
2934     * @since 3.0 Changed signature from indexOfAnyBut(String, String) to indexOfAnyBut(CharSequence, CharSequence)
2935     */
2936    public static int indexOfAnyBut(final CharSequence seq, final CharSequence searchChars) {
2937        if (isEmpty(seq) || isEmpty(searchChars)) {
2938            return INDEX_NOT_FOUND;
2939        }
2940        final int strLen = seq.length();
2941        for (int i = 0; i < strLen; i++) {
2942            final char ch = seq.charAt(i);
2943            final boolean chFound = CharSequenceUtils.indexOf(searchChars, ch, 0) >= 0;
2944            if (i + 1 < strLen && Character.isHighSurrogate(ch)) {
2945                final char ch2 = seq.charAt(i + 1);
2946                if (chFound && CharSequenceUtils.indexOf(searchChars, ch2, 0) < 0) {
2947                    return i;
2948                }
2949            } else if (!chFound) {
2950                return i;
2951            }
2952        }
2953        return INDEX_NOT_FOUND;
2954    }
2955
2956    /**
2957     * <p>Compares all CharSequences in an array and returns the index at which the
2958     * CharSequences begin to differ.</p>
2959     *
2960     * <p>For example,
2961     * {@code indexOfDifference(new String[] {"i am a machine", "i am a robot"}) -> 7}</p>
2962     *
2963     * <pre>
2964     * StringUtils.indexOfDifference(null) = -1
2965     * StringUtils.indexOfDifference(new String[] {}) = -1
2966     * StringUtils.indexOfDifference(new String[] {"abc"}) = -1
2967     * StringUtils.indexOfDifference(new String[] {null, null}) = -1
2968     * StringUtils.indexOfDifference(new String[] {"", ""}) = -1
2969     * StringUtils.indexOfDifference(new String[] {"", null}) = 0
2970     * StringUtils.indexOfDifference(new String[] {"abc", null, null}) = 0
2971     * StringUtils.indexOfDifference(new String[] {null, null, "abc"}) = 0
2972     * StringUtils.indexOfDifference(new String[] {"", "abc"}) = 0
2973     * StringUtils.indexOfDifference(new String[] {"abc", ""}) = 0
2974     * StringUtils.indexOfDifference(new String[] {"abc", "abc"}) = -1
2975     * StringUtils.indexOfDifference(new String[] {"abc", "a"}) = 1
2976     * StringUtils.indexOfDifference(new String[] {"ab", "abxyz"}) = 2
2977     * StringUtils.indexOfDifference(new String[] {"abcde", "abxyz"}) = 2
2978     * StringUtils.indexOfDifference(new String[] {"abcde", "xyz"}) = 0
2979     * StringUtils.indexOfDifference(new String[] {"xyz", "abcde"}) = 0
2980     * StringUtils.indexOfDifference(new String[] {"i am a machine", "i am a robot"}) = 7
2981     * </pre>
2982     *
2983     * @param css  array of CharSequences, entries may be null
2984     * @return the index where the strings begin to differ; -1 if they are all equal
2985     * @since 2.4
2986     * @since 3.0 Changed signature from indexOfDifference(String...) to indexOfDifference(CharSequence...)
2987     */
2988    public static int indexOfDifference(final CharSequence... css) {
2989        if (ArrayUtils.getLength(css) <= 1) {
2990            return INDEX_NOT_FOUND;
2991        }
2992        boolean anyStringNull = false;
2993        boolean allStringsNull = true;
2994        final int arrayLen = css.length;
2995        int shortestStrLen = Integer.MAX_VALUE;
2996        int longestStrLen = 0;
2997
2998        // find the min and max string lengths; this avoids checking to make
2999        // sure we are not exceeding the length of the string each time through
3000        // the bottom loop.
3001        for (final CharSequence cs : css) {
3002            if (cs == null) {
3003                anyStringNull = true;
3004                shortestStrLen = 0;
3005            } else {
3006                allStringsNull = false;
3007                shortestStrLen = Math.min(cs.length(), shortestStrLen);
3008                longestStrLen = Math.max(cs.length(), longestStrLen);
3009            }
3010        }
3011
3012        // handle lists containing all nulls or all empty strings
3013        if (allStringsNull || longestStrLen == 0 && !anyStringNull) {
3014            return INDEX_NOT_FOUND;
3015        }
3016
3017        // handle lists containing some nulls or some empty strings
3018        if (shortestStrLen == 0) {
3019            return 0;
3020        }
3021
3022        // find the position with the first difference across all strings
3023        int firstDiff = -1;
3024        for (int stringPos = 0; stringPos < shortestStrLen; stringPos++) {
3025            final char comparisonChar = css[0].charAt(stringPos);
3026            for (int arrayPos = 1; arrayPos < arrayLen; arrayPos++) {
3027                if (css[arrayPos].charAt(stringPos) != comparisonChar) {
3028                    firstDiff = stringPos;
3029                    break;
3030                }
3031            }
3032            if (firstDiff != -1) {
3033                break;
3034            }
3035        }
3036
3037        if (firstDiff == -1 && shortestStrLen != longestStrLen) {
3038            // we compared all of the characters up to the length of the
3039            // shortest string and didn't find a match, but the string lengths
3040            // vary, so return the length of the shortest string.
3041            return shortestStrLen;
3042        }
3043        return firstDiff;
3044    }
3045
3046    /**
3047     * <p>Compares two CharSequences, and returns the index at which the
3048     * CharSequences begin to differ.</p>
3049     *
3050     * <p>For example,
3051     * {@code indexOfDifference("i am a machine", "i am a robot") -> 7}</p>
3052     *
3053     * <pre>
3054     * StringUtils.indexOfDifference(null, null) = -1
3055     * StringUtils.indexOfDifference("", "") = -1
3056     * StringUtils.indexOfDifference("", "abc") = 0
3057     * StringUtils.indexOfDifference("abc", "") = 0
3058     * StringUtils.indexOfDifference("abc", "abc") = -1
3059     * StringUtils.indexOfDifference("ab", "abxyz") = 2
3060     * StringUtils.indexOfDifference("abcde", "abxyz") = 2
3061     * StringUtils.indexOfDifference("abcde", "xyz") = 0
3062     * </pre>
3063     *
3064     * @param cs1  the first CharSequence, may be null
3065     * @param cs2  the second CharSequence, may be null
3066     * @return the index where cs1 and cs2 begin to differ; -1 if they are equal
3067     * @since 2.0
3068     * @since 3.0 Changed signature from indexOfDifference(String, String) to
3069     * indexOfDifference(CharSequence, CharSequence)
3070     */
3071    public static int indexOfDifference(final CharSequence cs1, final CharSequence cs2) {
3072        if (cs1 == cs2) {
3073            return INDEX_NOT_FOUND;
3074        }
3075        if (cs1 == null || cs2 == null) {
3076            return 0;
3077        }
3078        int i;
3079        for (i = 0; i < cs1.length() && i < cs2.length(); ++i) {
3080            if (cs1.charAt(i) != cs2.charAt(i)) {
3081                break;
3082            }
3083        }
3084        if (i < cs2.length() || i < cs1.length()) {
3085            return i;
3086        }
3087        return INDEX_NOT_FOUND;
3088    }
3089
3090    /**
3091     * <p>Case in-sensitive find of the first index within a CharSequence.</p>
3092     *
3093     * <p>A {@code null} CharSequence will return {@code -1}.
3094     * A negative start position is treated as zero.
3095     * An empty ("") search CharSequence always matches.
3096     * A start position greater than the string length only matches
3097     * an empty search CharSequence.</p>
3098     *
3099     * <pre>
3100     * StringUtils.indexOfIgnoreCase(null, *)          = -1
3101     * StringUtils.indexOfIgnoreCase(*, null)          = -1
3102     * StringUtils.indexOfIgnoreCase("", "")           = 0
3103     * StringUtils.indexOfIgnoreCase("aabaabaa", "a")  = 0
3104     * StringUtils.indexOfIgnoreCase("aabaabaa", "b")  = 2
3105     * StringUtils.indexOfIgnoreCase("aabaabaa", "ab") = 1
3106     * </pre>
3107     *
3108     * @param str  the CharSequence to check, may be null
3109     * @param searchStr  the CharSequence to find, may be null
3110     * @return the first index of the search CharSequence,
3111     *  -1 if no match or {@code null} string input
3112     * @since 2.5
3113     * @since 3.0 Changed signature from indexOfIgnoreCase(String, String) to indexOfIgnoreCase(CharSequence, CharSequence)
3114     */
3115    public static int indexOfIgnoreCase(final CharSequence str, final CharSequence searchStr) {
3116        return indexOfIgnoreCase(str, searchStr, 0);
3117    }
3118
3119    /**
3120     * <p>Case in-sensitive find of the first index within a CharSequence
3121     * from the specified position.</p>
3122     *
3123     * <p>A {@code null} CharSequence will return {@code -1}.
3124     * A negative start position is treated as zero.
3125     * An empty ("") search CharSequence always matches.
3126     * A start position greater than the string length only matches
3127     * an empty search CharSequence.</p>
3128     *
3129     * <pre>
3130     * StringUtils.indexOfIgnoreCase(null, *, *)          = -1
3131     * StringUtils.indexOfIgnoreCase(*, null, *)          = -1
3132     * StringUtils.indexOfIgnoreCase("", "", 0)           = 0
3133     * StringUtils.indexOfIgnoreCase("aabaabaa", "A", 0)  = 0
3134     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 0)  = 2
3135     * StringUtils.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
3136     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 3)  = 5
3137     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 9)  = -1
3138     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
3139     * StringUtils.indexOfIgnoreCase("aabaabaa", "", 2)   = 2
3140     * StringUtils.indexOfIgnoreCase("abc", "", 9)        = -1
3141     * </pre>
3142     *
3143     * @param str  the CharSequence to check, may be null
3144     * @param searchStr  the CharSequence to find, may be null
3145     * @param startPos  the start position, negative treated as zero
3146     * @return the first index of the search CharSequence (always &ge; startPos),
3147     *  -1 if no match or {@code null} string input
3148     * @since 2.5
3149     * @since 3.0 Changed signature from indexOfIgnoreCase(String, String, int) to indexOfIgnoreCase(CharSequence, CharSequence, int)
3150     */
3151    public static int indexOfIgnoreCase(final CharSequence str, final CharSequence searchStr, int startPos) {
3152        if (str == null || searchStr == null) {
3153            return INDEX_NOT_FOUND;
3154        }
3155        if (startPos < 0) {
3156            startPos = 0;
3157        }
3158        final int endLimit = str.length() - searchStr.length() + 1;
3159        if (startPos > endLimit) {
3160            return INDEX_NOT_FOUND;
3161        }
3162        if (searchStr.length() == 0) {
3163            return startPos;
3164        }
3165        for (int i = startPos; i < endLimit; i++) {
3166            if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStr.length())) {
3167                return i;
3168            }
3169        }
3170        return INDEX_NOT_FOUND;
3171    }
3172
3173    /**
3174     * <p>Checks if all of the CharSequences are empty (""), null or whitespace only.</p>
3175     *
3176     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3177     *
3178     * <pre>
3179     * StringUtils.isAllBlank(null)             = true
3180     * StringUtils.isAllBlank(null, "foo")      = false
3181     * StringUtils.isAllBlank(null, null)       = true
3182     * StringUtils.isAllBlank("", "bar")        = false
3183     * StringUtils.isAllBlank("bob", "")        = false
3184     * StringUtils.isAllBlank("  bob  ", null)  = false
3185     * StringUtils.isAllBlank(" ", "bar")       = false
3186     * StringUtils.isAllBlank("foo", "bar")     = false
3187     * StringUtils.isAllBlank(new String[] {})  = true
3188     * </pre>
3189     *
3190     * @param css  the CharSequences to check, may be null or empty
3191     * @return {@code true} if all of the CharSequences are empty or null or whitespace only
3192     * @since 3.6
3193     */
3194    public static boolean isAllBlank(final CharSequence... css) {
3195        if (ArrayUtils.isEmpty(css)) {
3196            return true;
3197        }
3198        for (final CharSequence cs : css) {
3199            if (isNotBlank(cs)) {
3200               return false;
3201            }
3202        }
3203        return true;
3204    }
3205
3206    /**
3207     * <p>Checks if all of the CharSequences are empty ("") or null.</p>
3208     *
3209     * <pre>
3210     * StringUtils.isAllEmpty(null)             = true
3211     * StringUtils.isAllEmpty(null, "")         = true
3212     * StringUtils.isAllEmpty(new String[] {})  = true
3213     * StringUtils.isAllEmpty(null, "foo")      = false
3214     * StringUtils.isAllEmpty("", "bar")        = false
3215     * StringUtils.isAllEmpty("bob", "")        = false
3216     * StringUtils.isAllEmpty("  bob  ", null)  = false
3217     * StringUtils.isAllEmpty(" ", "bar")       = false
3218     * StringUtils.isAllEmpty("foo", "bar")     = false
3219     * </pre>
3220     *
3221     * @param css  the CharSequences to check, may be null or empty
3222     * @return {@code true} if all of the CharSequences are empty or null
3223     * @since 3.6
3224     */
3225    public static boolean isAllEmpty(final CharSequence... css) {
3226        if (ArrayUtils.isEmpty(css)) {
3227            return true;
3228        }
3229        for (final CharSequence cs : css) {
3230            if (isNotEmpty(cs)) {
3231                return false;
3232            }
3233        }
3234        return true;
3235    }
3236
3237    /**
3238     * <p>Checks if the CharSequence contains only lowercase characters.</p>
3239     *
3240     * <p>{@code null} will return {@code false}.
3241     * An empty CharSequence (length()=0) will return {@code false}.</p>
3242     *
3243     * <pre>
3244     * StringUtils.isAllLowerCase(null)   = false
3245     * StringUtils.isAllLowerCase("")     = false
3246     * StringUtils.isAllLowerCase("  ")   = false
3247     * StringUtils.isAllLowerCase("abc")  = true
3248     * StringUtils.isAllLowerCase("abC")  = false
3249     * StringUtils.isAllLowerCase("ab c") = false
3250     * StringUtils.isAllLowerCase("ab1c") = false
3251     * StringUtils.isAllLowerCase("ab/c") = false
3252     * </pre>
3253     *
3254     * @param cs  the CharSequence to check, may be null
3255     * @return {@code true} if only contains lowercase characters, and is non-null
3256     * @since 2.5
3257     * @since 3.0 Changed signature from isAllLowerCase(String) to isAllLowerCase(CharSequence)
3258     */
3259    public static boolean isAllLowerCase(final CharSequence cs) {
3260        if (isEmpty(cs)) {
3261            return false;
3262        }
3263        final int sz = cs.length();
3264        for (int i = 0; i < sz; i++) {
3265            if (!Character.isLowerCase(cs.charAt(i))) {
3266                return false;
3267            }
3268        }
3269        return true;
3270    }
3271
3272    /**
3273     * <p>Checks if the CharSequence contains only uppercase characters.</p>
3274     *
3275     * <p>{@code null} will return {@code false}.
3276     * An empty String (length()=0) will return {@code false}.</p>
3277     *
3278     * <pre>
3279     * StringUtils.isAllUpperCase(null)   = false
3280     * StringUtils.isAllUpperCase("")     = false
3281     * StringUtils.isAllUpperCase("  ")   = false
3282     * StringUtils.isAllUpperCase("ABC")  = true
3283     * StringUtils.isAllUpperCase("aBC")  = false
3284     * StringUtils.isAllUpperCase("A C")  = false
3285     * StringUtils.isAllUpperCase("A1C")  = false
3286     * StringUtils.isAllUpperCase("A/C")  = false
3287     * </pre>
3288     *
3289     * @param cs the CharSequence to check, may be null
3290     * @return {@code true} if only contains uppercase characters, and is non-null
3291     * @since 2.5
3292     * @since 3.0 Changed signature from isAllUpperCase(String) to isAllUpperCase(CharSequence)
3293     */
3294    public static boolean isAllUpperCase(final CharSequence cs) {
3295        if (isEmpty(cs)) {
3296            return false;
3297        }
3298        final int sz = cs.length();
3299        for (int i = 0; i < sz; i++) {
3300            if (!Character.isUpperCase(cs.charAt(i))) {
3301                return false;
3302            }
3303        }
3304        return true;
3305    }
3306
3307    /**
3308     * <p>Checks if the CharSequence contains only Unicode letters.</p>
3309     *
3310     * <p>{@code null} will return {@code false}.
3311     * An empty CharSequence (length()=0) will return {@code false}.</p>
3312     *
3313     * <pre>
3314     * StringUtils.isAlpha(null)   = false
3315     * StringUtils.isAlpha("")     = false
3316     * StringUtils.isAlpha("  ")   = false
3317     * StringUtils.isAlpha("abc")  = true
3318     * StringUtils.isAlpha("ab2c") = false
3319     * StringUtils.isAlpha("ab-c") = false
3320     * </pre>
3321     *
3322     * @param cs  the CharSequence to check, may be null
3323     * @return {@code true} if only contains letters, and is non-null
3324     * @since 3.0 Changed signature from isAlpha(String) to isAlpha(CharSequence)
3325     * @since 3.0 Changed "" to return false and not true
3326     */
3327    public static boolean isAlpha(final CharSequence cs) {
3328        if (isEmpty(cs)) {
3329            return false;
3330        }
3331        final int sz = cs.length();
3332        for (int i = 0; i < sz; i++) {
3333            if (!Character.isLetter(cs.charAt(i))) {
3334                return false;
3335            }
3336        }
3337        return true;
3338    }
3339
3340    /**
3341     * <p>Checks if the CharSequence contains only Unicode letters or digits.</p>
3342     *
3343     * <p>{@code null} will return {@code false}.
3344     * An empty CharSequence (length()=0) will return {@code false}.</p>
3345     *
3346     * <pre>
3347     * StringUtils.isAlphanumeric(null)   = false
3348     * StringUtils.isAlphanumeric("")     = false
3349     * StringUtils.isAlphanumeric("  ")   = false
3350     * StringUtils.isAlphanumeric("abc")  = true
3351     * StringUtils.isAlphanumeric("ab c") = false
3352     * StringUtils.isAlphanumeric("ab2c") = true
3353     * StringUtils.isAlphanumeric("ab-c") = false
3354     * </pre>
3355     *
3356     * @param cs  the CharSequence to check, may be null
3357     * @return {@code true} if only contains letters or digits,
3358     *  and is non-null
3359     * @since 3.0 Changed signature from isAlphanumeric(String) to isAlphanumeric(CharSequence)
3360     * @since 3.0 Changed "" to return false and not true
3361     */
3362    public static boolean isAlphanumeric(final CharSequence cs) {
3363        if (isEmpty(cs)) {
3364            return false;
3365        }
3366        final int sz = cs.length();
3367        for (int i = 0; i < sz; i++) {
3368            if (!Character.isLetterOrDigit(cs.charAt(i))) {
3369                return false;
3370            }
3371        }
3372        return true;
3373    }
3374
3375    /**
3376     * <p>Checks if the CharSequence contains only Unicode letters, digits
3377     * or space ({@code ' '}).</p>
3378     *
3379     * <p>{@code null} will return {@code false}.
3380     * An empty CharSequence (length()=0) will return {@code true}.</p>
3381     *
3382     * <pre>
3383     * StringUtils.isAlphanumericSpace(null)   = false
3384     * StringUtils.isAlphanumericSpace("")     = true
3385     * StringUtils.isAlphanumericSpace("  ")   = true
3386     * StringUtils.isAlphanumericSpace("abc")  = true
3387     * StringUtils.isAlphanumericSpace("ab c") = true
3388     * StringUtils.isAlphanumericSpace("ab2c") = true
3389     * StringUtils.isAlphanumericSpace("ab-c") = false
3390     * </pre>
3391     *
3392     * @param cs  the CharSequence to check, may be null
3393     * @return {@code true} if only contains letters, digits or space,
3394     *  and is non-null
3395     * @since 3.0 Changed signature from isAlphanumericSpace(String) to isAlphanumericSpace(CharSequence)
3396     */
3397    public static boolean isAlphanumericSpace(final CharSequence cs) {
3398        if (cs == null) {
3399            return false;
3400        }
3401        final int sz = cs.length();
3402        for (int i = 0; i < sz; i++) {
3403            final char nowChar = cs.charAt(i);
3404            if (nowChar != ' ' && !Character.isLetterOrDigit(nowChar) ) {
3405                return false;
3406            }
3407        }
3408        return true;
3409    }
3410
3411    /**
3412     * <p>Checks if the CharSequence contains only Unicode letters and
3413     * space (' ').</p>
3414     *
3415     * <p>{@code null} will return {@code false}
3416     * An empty CharSequence (length()=0) will return {@code true}.</p>
3417     *
3418     * <pre>
3419     * StringUtils.isAlphaSpace(null)   = false
3420     * StringUtils.isAlphaSpace("")     = true
3421     * StringUtils.isAlphaSpace("  ")   = true
3422     * StringUtils.isAlphaSpace("abc")  = true
3423     * StringUtils.isAlphaSpace("ab c") = true
3424     * StringUtils.isAlphaSpace("ab2c") = false
3425     * StringUtils.isAlphaSpace("ab-c") = false
3426     * </pre>
3427     *
3428     * @param cs  the CharSequence to check, may be null
3429     * @return {@code true} if only contains letters and space,
3430     *  and is non-null
3431     * @since 3.0 Changed signature from isAlphaSpace(String) to isAlphaSpace(CharSequence)
3432     */
3433    public static boolean isAlphaSpace(final CharSequence cs) {
3434        if (cs == null) {
3435            return false;
3436        }
3437        final int sz = cs.length();
3438        for (int i = 0; i < sz; i++) {
3439            final char nowChar = cs.charAt(i);
3440            if (nowChar != ' ' && !Character.isLetter(nowChar)) {
3441                return false;
3442            }
3443        }
3444        return true;
3445    }
3446
3447    /**
3448     * <p>Checks if any of the CharSequences are empty ("") or null or whitespace only.</p>
3449     *
3450     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3451     *
3452     * <pre>
3453     * StringUtils.isAnyBlank((String) null)    = true
3454     * StringUtils.isAnyBlank((String[]) null)  = false
3455     * StringUtils.isAnyBlank(null, "foo")      = true
3456     * StringUtils.isAnyBlank(null, null)       = true
3457     * StringUtils.isAnyBlank("", "bar")        = true
3458     * StringUtils.isAnyBlank("bob", "")        = true
3459     * StringUtils.isAnyBlank("  bob  ", null)  = true
3460     * StringUtils.isAnyBlank(" ", "bar")       = true
3461     * StringUtils.isAnyBlank(new String[] {})  = false
3462     * StringUtils.isAnyBlank(new String[]{""}) = true
3463     * StringUtils.isAnyBlank("foo", "bar")     = false
3464     * </pre>
3465     *
3466     * @param css  the CharSequences to check, may be null or empty
3467     * @return {@code true} if any of the CharSequences are empty or null or whitespace only
3468     * @since 3.2
3469     */
3470    public static boolean isAnyBlank(final CharSequence... css) {
3471        if (ArrayUtils.isEmpty(css)) {
3472            return false;
3473        }
3474        for (final CharSequence cs : css) {
3475            if (isBlank(cs)) {
3476                return true;
3477            }
3478        }
3479        return false;
3480    }
3481
3482    /**
3483     * <p>Checks if any of the CharSequences are empty ("") or null.</p>
3484     *
3485     * <pre>
3486     * StringUtils.isAnyEmpty((String) null)    = true
3487     * StringUtils.isAnyEmpty((String[]) null)  = false
3488     * StringUtils.isAnyEmpty(null, "foo")      = true
3489     * StringUtils.isAnyEmpty("", "bar")        = true
3490     * StringUtils.isAnyEmpty("bob", "")        = true
3491     * StringUtils.isAnyEmpty("  bob  ", null)  = true
3492     * StringUtils.isAnyEmpty(" ", "bar")       = false
3493     * StringUtils.isAnyEmpty("foo", "bar")     = false
3494     * StringUtils.isAnyEmpty(new String[]{})   = false
3495     * StringUtils.isAnyEmpty(new String[]{""}) = true
3496     * </pre>
3497     *
3498     * @param css  the CharSequences to check, may be null or empty
3499     * @return {@code true} if any of the CharSequences are empty or null
3500     * @since 3.2
3501     */
3502    public static boolean isAnyEmpty(final CharSequence... css) {
3503        if (ArrayUtils.isEmpty(css)) {
3504            return false;
3505        }
3506        for (final CharSequence cs : css) {
3507            if (isEmpty(cs)) {
3508                return true;
3509            }
3510        }
3511        return false;
3512    }
3513
3514    /**
3515     * <p>Checks if the CharSequence contains only ASCII printable characters.</p>
3516     *
3517     * <p>{@code null} will return {@code false}.
3518     * An empty CharSequence (length()=0) will return {@code true}.</p>
3519     *
3520     * <pre>
3521     * StringUtils.isAsciiPrintable(null)     = false
3522     * StringUtils.isAsciiPrintable("")       = true
3523     * StringUtils.isAsciiPrintable(" ")      = true
3524     * StringUtils.isAsciiPrintable("Ceki")   = true
3525     * StringUtils.isAsciiPrintable("ab2c")   = true
3526     * StringUtils.isAsciiPrintable("!ab-c~") = true
3527     * StringUtils.isAsciiPrintable("\u0020") = true
3528     * StringUtils.isAsciiPrintable("\u0021") = true
3529     * StringUtils.isAsciiPrintable("\u007e") = true
3530     * StringUtils.isAsciiPrintable("\u007f") = false
3531     * StringUtils.isAsciiPrintable("Ceki G\u00fclc\u00fc") = false
3532     * </pre>
3533     *
3534     * @param cs the CharSequence to check, may be null
3535     * @return {@code true} if every character is in the range
3536     *  32 thru 126
3537     * @since 2.1
3538     * @since 3.0 Changed signature from isAsciiPrintable(String) to isAsciiPrintable(CharSequence)
3539     */
3540    public static boolean isAsciiPrintable(final CharSequence cs) {
3541        if (cs == null) {
3542            return false;
3543        }
3544        final int sz = cs.length();
3545        for (int i = 0; i < sz; i++) {
3546            if (!CharUtils.isAsciiPrintable(cs.charAt(i))) {
3547                return false;
3548            }
3549        }
3550        return true;
3551    }
3552
3553    /**
3554     * <p>Checks if a CharSequence is empty (""), null or whitespace only.</p>
3555     *
3556     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3557     *
3558     * <pre>
3559     * StringUtils.isBlank(null)      = true
3560     * StringUtils.isBlank("")        = true
3561     * StringUtils.isBlank(" ")       = true
3562     * StringUtils.isBlank("bob")     = false
3563     * StringUtils.isBlank("  bob  ") = false
3564     * </pre>
3565     *
3566     * @param cs  the CharSequence to check, may be null
3567     * @return {@code true} if the CharSequence is null, empty or whitespace only
3568     * @since 2.0
3569     * @since 3.0 Changed signature from isBlank(String) to isBlank(CharSequence)
3570     */
3571    public static boolean isBlank(final CharSequence cs) {
3572        final int strLen = length(cs);
3573        if (strLen == 0) {
3574            return true;
3575        }
3576        for (int i = 0; i < strLen; i++) {
3577            if (!Character.isWhitespace(cs.charAt(i))) {
3578                return false;
3579            }
3580        }
3581        return true;
3582    }
3583
3584    /**
3585     * <p>Checks if a CharSequence is empty ("") or null.</p>
3586     *
3587     * <pre>
3588     * StringUtils.isEmpty(null)      = true
3589     * StringUtils.isEmpty("")        = true
3590     * StringUtils.isEmpty(" ")       = false
3591     * StringUtils.isEmpty("bob")     = false
3592     * StringUtils.isEmpty("  bob  ") = false
3593     * </pre>
3594     *
3595     * <p>NOTE: This method changed in Lang version 2.0.
3596     * It no longer trims the CharSequence.
3597     * That functionality is available in isBlank().</p>
3598     *
3599     * @param cs  the CharSequence to check, may be null
3600     * @return {@code true} if the CharSequence is empty or null
3601     * @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
3602     */
3603    public static boolean isEmpty(final CharSequence cs) {
3604        return cs == null || cs.length() == 0;
3605    }
3606
3607    /**
3608     * <p>Checks if the CharSequence contains mixed casing of both uppercase and lowercase characters.</p>
3609     *
3610     * <p>{@code null} will return {@code false}. An empty CharSequence ({@code length()=0}) will return
3611     * {@code false}.</p>
3612     *
3613     * <pre>
3614     * StringUtils.isMixedCase(null)    = false
3615     * StringUtils.isMixedCase("")      = false
3616     * StringUtils.isMixedCase("ABC")   = false
3617     * StringUtils.isMixedCase("abc")   = false
3618     * StringUtils.isMixedCase("aBc")   = true
3619     * StringUtils.isMixedCase("A c")   = true
3620     * StringUtils.isMixedCase("A1c")   = true
3621     * StringUtils.isMixedCase("a/C")   = true
3622     * StringUtils.isMixedCase("aC\t")  = true
3623     * </pre>
3624     *
3625     * @param cs the CharSequence to check, may be null
3626     * @return {@code true} if the CharSequence contains both uppercase and lowercase characters
3627     * @since 3.5
3628     */
3629    public static boolean isMixedCase(final CharSequence cs) {
3630        if (isEmpty(cs) || cs.length() == 1) {
3631            return false;
3632        }
3633        boolean containsUppercase = false;
3634        boolean containsLowercase = false;
3635        final int sz = cs.length();
3636        for (int i = 0; i < sz; i++) {
3637            if (containsUppercase && containsLowercase) {
3638                return true;
3639            } else if (Character.isUpperCase(cs.charAt(i))) {
3640                containsUppercase = true;
3641            } else if (Character.isLowerCase(cs.charAt(i))) {
3642                containsLowercase = true;
3643            }
3644        }
3645        return containsUppercase && containsLowercase;
3646    }
3647
3648    /**
3649     * <p>Checks if none of the CharSequences are empty (""), null or whitespace only.</p>
3650     *
3651     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3652     *
3653     * <pre>
3654     * StringUtils.isNoneBlank((String) null)    = false
3655     * StringUtils.isNoneBlank((String[]) null)  = true
3656     * StringUtils.isNoneBlank(null, "foo")      = false
3657     * StringUtils.isNoneBlank(null, null)       = false
3658     * StringUtils.isNoneBlank("", "bar")        = false
3659     * StringUtils.isNoneBlank("bob", "")        = false
3660     * StringUtils.isNoneBlank("  bob  ", null)  = false
3661     * StringUtils.isNoneBlank(" ", "bar")       = false
3662     * StringUtils.isNoneBlank(new String[] {})  = true
3663     * StringUtils.isNoneBlank(new String[]{""}) = false
3664     * StringUtils.isNoneBlank("foo", "bar")     = true
3665     * </pre>
3666     *
3667     * @param css  the CharSequences to check, may be null or empty
3668     * @return {@code true} if none of the CharSequences are empty or null or whitespace only
3669     * @since 3.2
3670     */
3671    public static boolean isNoneBlank(final CharSequence... css) {
3672      return !isAnyBlank(css);
3673    }
3674
3675    /**
3676     * <p>Checks if none of the CharSequences are empty ("") or null.</p>
3677     *
3678     * <pre>
3679     * StringUtils.isNoneEmpty((String) null)    = false
3680     * StringUtils.isNoneEmpty((String[]) null)  = true
3681     * StringUtils.isNoneEmpty(null, "foo")      = false
3682     * StringUtils.isNoneEmpty("", "bar")        = false
3683     * StringUtils.isNoneEmpty("bob", "")        = false
3684     * StringUtils.isNoneEmpty("  bob  ", null)  = false
3685     * StringUtils.isNoneEmpty(new String[] {})  = true
3686     * StringUtils.isNoneEmpty(new String[]{""}) = false
3687     * StringUtils.isNoneEmpty(" ", "bar")       = true
3688     * StringUtils.isNoneEmpty("foo", "bar")     = true
3689     * </pre>
3690     *
3691     * @param css  the CharSequences to check, may be null or empty
3692     * @return {@code true} if none of the CharSequences are empty or null
3693     * @since 3.2
3694     */
3695    public static boolean isNoneEmpty(final CharSequence... css) {
3696      return !isAnyEmpty(css);
3697    }
3698
3699    /**
3700     * <p>Checks if a CharSequence is not empty (""), not null and not whitespace only.</p>
3701     *
3702     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3703     *
3704     * <pre>
3705     * StringUtils.isNotBlank(null)      = false
3706     * StringUtils.isNotBlank("")        = false
3707     * StringUtils.isNotBlank(" ")       = false
3708     * StringUtils.isNotBlank("bob")     = true
3709     * StringUtils.isNotBlank("  bob  ") = true
3710     * </pre>
3711     *
3712     * @param cs  the CharSequence to check, may be null
3713     * @return {@code true} if the CharSequence is
3714     *  not empty and not null and not whitespace only
3715     * @since 2.0
3716     * @since 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)
3717     */
3718    public static boolean isNotBlank(final CharSequence cs) {
3719        return !isBlank(cs);
3720    }
3721
3722    /**
3723     * <p>Checks if a CharSequence is not empty ("") and not null.</p>
3724     *
3725     * <pre>
3726     * StringUtils.isNotEmpty(null)      = false
3727     * StringUtils.isNotEmpty("")        = false
3728     * StringUtils.isNotEmpty(" ")       = true
3729     * StringUtils.isNotEmpty("bob")     = true
3730     * StringUtils.isNotEmpty("  bob  ") = true
3731     * </pre>
3732     *
3733     * @param cs  the CharSequence to check, may be null
3734     * @return {@code true} if the CharSequence is not empty and not null
3735     * @since 3.0 Changed signature from isNotEmpty(String) to isNotEmpty(CharSequence)
3736     */
3737    public static boolean isNotEmpty(final CharSequence cs) {
3738        return !isEmpty(cs);
3739    }
3740
3741    /**
3742     * <p>Checks if the CharSequence contains only Unicode digits.
3743     * A decimal point is not a Unicode digit and returns false.</p>
3744     *
3745     * <p>{@code null} will return {@code false}.
3746     * An empty CharSequence (length()=0) will return {@code false}.</p>
3747     *
3748     * <p>Note that the method does not allow for a leading sign, either positive or negative.
3749     * Also, if a String passes the numeric test, it may still generate a NumberFormatException
3750     * when parsed by Integer.parseInt or Long.parseLong, e.g. if the value is outside the range
3751     * for int or long respectively.</p>
3752     *
3753     * <pre>
3754     * StringUtils.isNumeric(null)   = false
3755     * StringUtils.isNumeric("")     = false
3756     * StringUtils.isNumeric("  ")   = false
3757     * StringUtils.isNumeric("123")  = true
3758     * StringUtils.isNumeric("\u0967\u0968\u0969")  = true
3759     * StringUtils.isNumeric("12 3") = false
3760     * StringUtils.isNumeric("ab2c") = false
3761     * StringUtils.isNumeric("12-3") = false
3762     * StringUtils.isNumeric("12.3") = false
3763     * StringUtils.isNumeric("-123") = false
3764     * StringUtils.isNumeric("+123") = false
3765     * </pre>
3766     *
3767     * @param cs  the CharSequence to check, may be null
3768     * @return {@code true} if only contains digits, and is non-null
3769     * @since 3.0 Changed signature from isNumeric(String) to isNumeric(CharSequence)
3770     * @since 3.0 Changed "" to return false and not true
3771     */
3772    public static boolean isNumeric(final CharSequence cs) {
3773        if (isEmpty(cs)) {
3774            return false;
3775        }
3776        final int sz = cs.length();
3777        for (int i = 0; i < sz; i++) {
3778            if (!Character.isDigit(cs.charAt(i))) {
3779                return false;
3780            }
3781        }
3782        return true;
3783    }
3784
3785    /**
3786     * <p>Checks if the CharSequence contains only Unicode digits or space
3787     * ({@code ' '}).
3788     * A decimal point is not a Unicode digit and returns false.</p>
3789     *
3790     * <p>{@code null} will return {@code false}.
3791     * An empty CharSequence (length()=0) will return {@code true}.</p>
3792     *
3793     * <pre>
3794     * StringUtils.isNumericSpace(null)   = false
3795     * StringUtils.isNumericSpace("")     = true
3796     * StringUtils.isNumericSpace("  ")   = true
3797     * StringUtils.isNumericSpace("123")  = true
3798     * StringUtils.isNumericSpace("12 3") = true
3799     * StringUtils.isNumericSpace("\u0967\u0968\u0969")  = true
3800     * StringUtils.isNumericSpace("\u0967\u0968 \u0969")  = true
3801     * StringUtils.isNumericSpace("ab2c") = false
3802     * StringUtils.isNumericSpace("12-3") = false
3803     * StringUtils.isNumericSpace("12.3") = false
3804     * </pre>
3805     *
3806     * @param cs  the CharSequence to check, may be null
3807     * @return {@code true} if only contains digits or space,
3808     *  and is non-null
3809     * @since 3.0 Changed signature from isNumericSpace(String) to isNumericSpace(CharSequence)
3810     */
3811    public static boolean isNumericSpace(final CharSequence cs) {
3812        if (cs == null) {
3813            return false;
3814        }
3815        final int sz = cs.length();
3816        for (int i = 0; i < sz; i++) {
3817            final char nowChar = cs.charAt(i);
3818            if (nowChar != ' ' && !Character.isDigit(nowChar)) {
3819                return false;
3820            }
3821        }
3822        return true;
3823    }
3824
3825    /**
3826     * <p>Checks if the CharSequence contains only whitespace.</p>
3827     *
3828     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3829     *
3830     * <p>{@code null} will return {@code false}.
3831     * An empty CharSequence (length()=0) will return {@code true}.</p>
3832     *
3833     * <pre>
3834     * StringUtils.isWhitespace(null)   = false
3835     * StringUtils.isWhitespace("")     = true
3836     * StringUtils.isWhitespace("  ")   = true
3837     * StringUtils.isWhitespace("abc")  = false
3838     * StringUtils.isWhitespace("ab2c") = false
3839     * StringUtils.isWhitespace("ab-c") = false
3840     * </pre>
3841     *
3842     * @param cs  the CharSequence to check, may be null
3843     * @return {@code true} if only contains whitespace, and is non-null
3844     * @since 2.0
3845     * @since 3.0 Changed signature from isWhitespace(String) to isWhitespace(CharSequence)
3846     */
3847    public static boolean isWhitespace(final CharSequence cs) {
3848        if (cs == null) {
3849            return false;
3850        }
3851        final int sz = cs.length();
3852        for (int i = 0; i < sz; i++) {
3853            if (!Character.isWhitespace(cs.charAt(i))) {
3854                return false;
3855            }
3856        }
3857        return true;
3858    }
3859
3860    /**
3861     * <p>
3862     * Joins the elements of the provided array into a single String containing the provided list of elements.
3863     * </p>
3864     *
3865     * <p>
3866     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3867     * by empty strings.
3868     * </p>
3869     *
3870     * <pre>
3871     * StringUtils.join(null, *)              = null
3872     * StringUtils.join([], *)                = ""
3873     * StringUtils.join([null], *)            = ""
3874     * StringUtils.join([false, false], ';')  = "false;false"
3875     * </pre>
3876     *
3877     * @param array
3878     *            the array of values to join together, may be null
3879     * @param delimiter
3880     *            the separator character to use
3881     * @return the joined String, {@code null} if null array input
3882     * @since 3.12.0
3883     */
3884    public static String join(final boolean[] array, final char delimiter) {
3885        if (array == null) {
3886            return null;
3887        }
3888        return join(array, delimiter, 0, array.length);
3889    }
3890
3891    /**
3892     * <p>
3893     * Joins the elements of the provided array into a single String containing the provided list of elements.
3894     * </p>
3895     *
3896     * <p>
3897     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3898     * by empty strings.
3899     * </p>
3900     *
3901     * <pre>
3902     * StringUtils.join(null, *)                   = null
3903     * StringUtils.join([], *)                     = ""
3904     * StringUtils.join([null], *)                 = ""
3905     * StringUtils.join([true, false, true], ';')  = "true;false;true"
3906     * </pre>
3907     *
3908     * @param array
3909     *            the array of values to join together, may be null
3910     * @param delimiter
3911     *            the separator character to use
3912     * @param startIndex
3913     *            the first index to start joining from. It is an error to pass in a start index past the end of the
3914     *            array
3915     * @param endIndex
3916     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
3917     *            the array
3918     * @return the joined String, {@code null} if null array input
3919     * @since 3.12.0
3920     */
3921    public static String join(final boolean[] array, final char delimiter, final int startIndex, final int endIndex) {
3922        if (array == null) {
3923            return null;
3924        }
3925        if (endIndex - startIndex <= 0) {
3926            return EMPTY;
3927        }
3928        final StringJoiner joiner = newStringJoiner(delimiter);
3929        for (int i = startIndex; i < endIndex; i++) {
3930            joiner.add(String.valueOf(array[i]));
3931        }
3932        return joiner.toString();
3933    }
3934
3935    /**
3936     * <p>
3937     * Joins the elements of the provided array into a single String containing the provided list of elements.
3938     * </p>
3939     *
3940     * <p>
3941     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3942     * by empty strings.
3943     * </p>
3944     *
3945     * <pre>
3946     * StringUtils.join(null, *)               = null
3947     * StringUtils.join([], *)                 = ""
3948     * StringUtils.join([null], *)             = ""
3949     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3950     * StringUtils.join([1, 2, 3], null) = "123"
3951     * </pre>
3952     *
3953     * @param array
3954     *            the array of values to join together, may be null
3955     * @param delimiter
3956     *            the separator character to use
3957     * @return the joined String, {@code null} if null array input
3958     * @since 3.2
3959     */
3960    public static String join(final byte[] array, final char delimiter) {
3961        if (array == null) {
3962            return null;
3963        }
3964        return join(array, delimiter, 0, array.length);
3965    }
3966
3967    /**
3968     * <p>
3969     * Joins the elements of the provided array into a single String containing the provided list of elements.
3970     * </p>
3971     *
3972     * <p>
3973     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3974     * by empty strings.
3975     * </p>
3976     *
3977     * <pre>
3978     * StringUtils.join(null, *)               = null
3979     * StringUtils.join([], *)                 = ""
3980     * StringUtils.join([null], *)             = ""
3981     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3982     * StringUtils.join([1, 2, 3], null) = "123"
3983     * </pre>
3984     *
3985     * @param array
3986     *            the array of values to join together, may be null
3987     * @param delimiter
3988     *            the separator character to use
3989     * @param startIndex
3990     *            the first index to start joining from. It is an error to pass in a start index past the end of the
3991     *            array
3992     * @param endIndex
3993     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
3994     *            the array
3995     * @return the joined String, {@code null} if null array input
3996     * @since 3.2
3997     */
3998    public static String join(final byte[] array, final char delimiter, final int startIndex, final int endIndex) {
3999        if (array == null) {
4000            return null;
4001        }
4002        if (endIndex - startIndex <= 0) {
4003            return EMPTY;
4004        }
4005        final StringJoiner joiner = newStringJoiner(delimiter);
4006        for (int i = startIndex; i < endIndex; i++) {
4007            joiner.add(String.valueOf(array[i]));
4008        }
4009        return joiner.toString();
4010    }
4011
4012    /**
4013     * <p>
4014     * Joins the elements of the provided array into a single String containing the provided list of elements.
4015     * </p>
4016     *
4017     * <p>
4018     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4019     * by empty strings.
4020     * </p>
4021     *
4022     * <pre>
4023     * StringUtils.join(null, *)               = null
4024     * StringUtils.join([], *)                 = ""
4025     * StringUtils.join([null], *)             = ""
4026     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4027     * StringUtils.join([1, 2, 3], null) = "123"
4028     * </pre>
4029     *
4030     * @param array
4031     *            the array of values to join together, may be null
4032     * @param delimiter
4033     *            the separator character to use
4034     * @return the joined String, {@code null} if null array input
4035     * @since 3.2
4036     */
4037    public static String join(final char[] array, final char delimiter) {
4038        if (array == null) {
4039            return null;
4040        }
4041        return join(array, delimiter, 0, array.length);
4042    }
4043
4044    /**
4045     * <p>
4046     * Joins the elements of the provided array into a single String containing the provided list of elements.
4047     * </p>
4048     *
4049     * <p>
4050     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4051     * by empty strings.
4052     * </p>
4053     *
4054     * <pre>
4055     * StringUtils.join(null, *)               = null
4056     * StringUtils.join([], *)                 = ""
4057     * StringUtils.join([null], *)             = ""
4058     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4059     * StringUtils.join([1, 2, 3], null) = "123"
4060     * </pre>
4061     *
4062     * @param array
4063     *            the array of values to join together, may be null
4064     * @param delimiter
4065     *            the separator character to use
4066     * @param startIndex
4067     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4068     *            array
4069     * @param endIndex
4070     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4071     *            the array
4072     * @return the joined String, {@code null} if null array input
4073     * @since 3.2
4074     */
4075    public static String join(final char[] array, final char delimiter, final int startIndex, final int endIndex) {
4076        if (array == null) {
4077            return null;
4078        }
4079        if (endIndex - startIndex <= 0) {
4080            return EMPTY;
4081        }
4082        final StringJoiner joiner = newStringJoiner(delimiter);
4083        for (int i = startIndex; i < endIndex; i++) {
4084            joiner.add(String.valueOf(array[i]));
4085        }
4086        return joiner.toString();
4087    }
4088
4089    /**
4090     * <p>
4091     * Joins the elements of the provided array into a single String containing the provided list of elements.
4092     * </p>
4093     *
4094     * <p>
4095     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4096     * by empty strings.
4097     * </p>
4098     *
4099     * <pre>
4100     * StringUtils.join(null, *)               = null
4101     * StringUtils.join([], *)                 = ""
4102     * StringUtils.join([null], *)             = ""
4103     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4104     * StringUtils.join([1, 2, 3], null) = "123"
4105     * </pre>
4106     *
4107     * @param array
4108     *            the array of values to join together, may be null
4109     * @param delimiter
4110     *            the separator character to use
4111     * @return the joined String, {@code null} if null array input
4112     * @since 3.2
4113     */
4114    public static String join(final double[] array, final char delimiter) {
4115        if (array == null) {
4116            return null;
4117        }
4118        return join(array, delimiter, 0, array.length);
4119    }
4120
4121    /**
4122     * <p>
4123     * Joins the elements of the provided array into a single String containing the provided list of elements.
4124     * </p>
4125     *
4126     * <p>
4127     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4128     * by empty strings.
4129     * </p>
4130     *
4131     * <pre>
4132     * StringUtils.join(null, *)               = null
4133     * StringUtils.join([], *)                 = ""
4134     * StringUtils.join([null], *)             = ""
4135     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4136     * StringUtils.join([1, 2, 3], null) = "123"
4137     * </pre>
4138     *
4139     * @param array
4140     *            the array of values to join together, may be null
4141     * @param delimiter
4142     *            the separator character to use
4143     * @param startIndex
4144     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4145     *            array
4146     * @param endIndex
4147     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4148     *            the array
4149     * @return the joined String, {@code null} if null array input
4150     * @since 3.2
4151     */
4152    public static String join(final double[] array, final char delimiter, final int startIndex, final int endIndex) {
4153        if (array == null) {
4154            return null;
4155        }
4156        if (endIndex - startIndex <= 0) {
4157            return EMPTY;
4158        }
4159        final StringJoiner joiner = newStringJoiner(delimiter);
4160        for (int i = startIndex; i < endIndex; i++) {
4161            joiner.add(String.valueOf(array[i]));
4162        }
4163        return joiner.toString();
4164    }
4165
4166    /**
4167     * <p>
4168     * Joins the elements of the provided array into a single String containing the provided list of elements.
4169     * </p>
4170     *
4171     * <p>
4172     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4173     * by empty strings.
4174     * </p>
4175     *
4176     * <pre>
4177     * StringUtils.join(null, *)               = null
4178     * StringUtils.join([], *)                 = ""
4179     * StringUtils.join([null], *)             = ""
4180     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4181     * StringUtils.join([1, 2, 3], null) = "123"
4182     * </pre>
4183     *
4184     * @param array
4185     *            the array of values to join together, may be null
4186     * @param delimiter
4187     *            the separator character to use
4188     * @return the joined String, {@code null} if null array input
4189     * @since 3.2
4190     */
4191    public static String join(final float[] array, final char delimiter) {
4192        if (array == null) {
4193            return null;
4194        }
4195        return join(array, delimiter, 0, array.length);
4196    }
4197
4198    /**
4199     * <p>
4200     * Joins the elements of the provided array into a single String containing the provided list of elements.
4201     * </p>
4202     *
4203     * <p>
4204     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4205     * by empty strings.
4206     * </p>
4207     *
4208     * <pre>
4209     * StringUtils.join(null, *)               = null
4210     * StringUtils.join([], *)                 = ""
4211     * StringUtils.join([null], *)             = ""
4212     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4213     * StringUtils.join([1, 2, 3], null) = "123"
4214     * </pre>
4215     *
4216     * @param array
4217     *            the array of values to join together, may be null
4218     * @param delimiter
4219     *            the separator character to use
4220     * @param startIndex
4221     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4222     *            array
4223     * @param endIndex
4224     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4225     *            the array
4226     * @return the joined String, {@code null} if null array input
4227     * @since 3.2
4228     */
4229    public static String join(final float[] array, final char delimiter, final int startIndex, final int endIndex) {
4230        if (array == null) {
4231            return null;
4232        }
4233        if (endIndex - startIndex <= 0) {
4234            return EMPTY;
4235        }
4236        final StringJoiner joiner = newStringJoiner(delimiter);
4237        for (int i = startIndex; i < endIndex; i++) {
4238            joiner.add(String.valueOf(array[i]));
4239        }
4240        return joiner.toString();
4241    }
4242
4243    /**
4244     * <p>
4245     * Joins the elements of the provided array into a single String containing the provided list of elements.
4246     * </p>
4247     *
4248     * <p>
4249     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4250     * by empty strings.
4251     * </p>
4252     *
4253     * <pre>
4254     * StringUtils.join(null, *)               = null
4255     * StringUtils.join([], *)                 = ""
4256     * StringUtils.join([null], *)             = ""
4257     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4258     * StringUtils.join([1, 2, 3], null) = "123"
4259     * </pre>
4260     *
4261     * @param array
4262     *            the array of values to join together, may be null
4263     * @param separator
4264     *            the separator character to use
4265     * @return the joined String, {@code null} if null array input
4266     * @since 3.2
4267     */
4268    public static String join(final int[] array, final char separator) {
4269        if (array == null) {
4270            return null;
4271        }
4272        return join(array, separator, 0, array.length);
4273    }
4274
4275    /**
4276     * <p>
4277     * Joins the elements of the provided array into a single String containing the provided list of elements.
4278     * </p>
4279     *
4280     * <p>
4281     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4282     * by empty strings.
4283     * </p>
4284     *
4285     * <pre>
4286     * StringUtils.join(null, *)               = null
4287     * StringUtils.join([], *)                 = ""
4288     * StringUtils.join([null], *)             = ""
4289     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4290     * StringUtils.join([1, 2, 3], null) = "123"
4291     * </pre>
4292     *
4293     * @param array
4294     *            the array of values to join together, may be null
4295     * @param delimiter
4296     *            the separator character to use
4297     * @param startIndex
4298     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4299     *            array
4300     * @param endIndex
4301     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4302     *            the array
4303     * @return the joined String, {@code null} if null array input
4304     * @since 3.2
4305     */
4306    public static String join(final int[] array, final char delimiter, final int startIndex, final int endIndex) {
4307        if (array == null) {
4308            return null;
4309        }
4310        if (endIndex - startIndex <= 0) {
4311            return EMPTY;
4312        }
4313        final StringJoiner joiner = newStringJoiner(delimiter);
4314        for (int i = startIndex; i < endIndex; i++) {
4315            joiner.add(String.valueOf(array[i]));
4316        }
4317        return joiner.toString();
4318    }
4319
4320    /**
4321     * <p>Joins the elements of the provided {@code Iterable} into
4322     * a single String containing the provided elements.</p>
4323     *
4324     * <p>No delimiter is added before or after the list. Null objects or empty
4325     * strings within the iteration are represented by empty strings.</p>
4326     *
4327     * <p>See the examples here: {@link #join(Object[],char)}. </p>
4328     *
4329     * @param iterable  the {@code Iterable} providing the values to join together, may be null
4330     * @param separator  the separator character to use
4331     * @return the joined String, {@code null} if null iterator input
4332     * @since 2.3
4333     */
4334    public static String join(final Iterable<?> iterable, final char separator) {
4335        if (iterable == null) {
4336            return null;
4337        }
4338        return join(iterable.iterator(), separator);
4339    }
4340
4341    /**
4342     * <p>Joins the elements of the provided {@code Iterable} into
4343     * a single String containing the provided elements.</p>
4344     *
4345     * <p>No delimiter is added before or after the list.
4346     * A {@code null} separator is the same as an empty String ("").</p>
4347     *
4348     * <p>See the examples here: {@link #join(Object[],String)}. </p>
4349     *
4350     * @param iterable  the {@code Iterable} providing the values to join together, may be null
4351     * @param separator  the separator character to use, null treated as ""
4352     * @return the joined String, {@code null} if null iterator input
4353     * @since 2.3
4354     */
4355    public static String join(final Iterable<?> iterable, final String separator) {
4356        if (iterable == null) {
4357            return null;
4358        }
4359        return join(iterable.iterator(), separator);
4360    }
4361
4362    /**
4363     * <p>Joins the elements of the provided {@code Iterator} into
4364     * a single String containing the provided elements.</p>
4365     *
4366     * <p>No delimiter is added before or after the list. Null objects or empty
4367     * strings within the iteration are represented by empty strings.</p>
4368     *
4369     * <p>See the examples here: {@link #join(Object[],char)}. </p>
4370     *
4371     * @param iterator  the {@code Iterator} of values to join together, may be null
4372     * @param separator  the separator character to use
4373     * @return the joined String, {@code null} if null iterator input
4374     * @since 2.0
4375     */
4376    public static String join(final Iterator<?> iterator, final char separator) {
4377
4378        // handle null, zero and one elements before building a buffer
4379        if (iterator == null) {
4380            return null;
4381        }
4382        if (!iterator.hasNext()) {
4383            return EMPTY;
4384        }
4385        final Object first = iterator.next();
4386        if (!iterator.hasNext()) {
4387            return toStringOrEmpty(first);
4388        }
4389
4390        // two or more elements
4391        final StringBuilder buf = new StringBuilder(STRING_BUILDER_SIZE); // Java default is 16, probably too small
4392        if (first != null) {
4393            buf.append(first);
4394        }
4395
4396        while (iterator.hasNext()) {
4397            buf.append(separator);
4398            final Object obj = iterator.next();
4399            if (obj != null) {
4400                buf.append(obj);
4401            }
4402        }
4403
4404        return buf.toString();
4405    }
4406
4407    /**
4408     * <p>Joins the elements of the provided {@code Iterator} into
4409     * a single String containing the provided elements.</p>
4410     *
4411     * <p>No delimiter is added before or after the list.
4412     * A {@code null} separator is the same as an empty String ("").</p>
4413     *
4414     * <p>See the examples here: {@link #join(Object[],String)}. </p>
4415     *
4416     * @param iterator  the {@code Iterator} of values to join together, may be null
4417     * @param separator  the separator character to use, null treated as ""
4418     * @return the joined String, {@code null} if null iterator input
4419     */
4420    public static String join(final Iterator<?> iterator, final String separator) {
4421
4422        // handle null, zero and one elements before building a buffer
4423        if (iterator == null) {
4424            return null;
4425        }
4426        if (!iterator.hasNext()) {
4427            return EMPTY;
4428        }
4429        final Object first = iterator.next();
4430        if (!iterator.hasNext()) {
4431            return Objects.toString(first, "");
4432        }
4433
4434        // two or more elements
4435        final StringBuilder buf = new StringBuilder(STRING_BUILDER_SIZE); // Java default is 16, probably too small
4436        if (first != null) {
4437            buf.append(first);
4438        }
4439
4440        while (iterator.hasNext()) {
4441            if (separator != null) {
4442                buf.append(separator);
4443            }
4444            final Object obj = iterator.next();
4445            if (obj != null) {
4446                buf.append(obj);
4447            }
4448        }
4449        return buf.toString();
4450    }
4451
4452    /**
4453     * <p>Joins the elements of the provided {@code List} into a single String
4454     * containing the provided list of elements.</p>
4455     *
4456     * <p>No delimiter is added before or after the list.
4457     * Null objects or empty strings within the array are represented by
4458     * empty strings.</p>
4459     *
4460     * <pre>
4461     * StringUtils.join(null, *)               = null
4462     * StringUtils.join([], *)                 = ""
4463     * StringUtils.join([null], *)             = ""
4464     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4465     * StringUtils.join(["a", "b", "c"], null) = "abc"
4466     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4467     * </pre>
4468     *
4469     * @param list  the {@code List} of values to join together, may be null
4470     * @param separator  the separator character to use
4471     * @param startIndex the first index to start joining from.  It is
4472     * an error to pass in a start index past the end of the list
4473     * @param endIndex the index to stop joining from (exclusive). It is
4474     * an error to pass in an end index past the end of the list
4475     * @return the joined String, {@code null} if null list input
4476     * @since 3.8
4477     */
4478    public static String join(final List<?> list, final char separator, final int startIndex, final int endIndex) {
4479        if (list == null) {
4480            return null;
4481        }
4482        final int noOfItems = endIndex - startIndex;
4483        if (noOfItems <= 0) {
4484            return EMPTY;
4485        }
4486        final List<?> subList = list.subList(startIndex, endIndex);
4487        return join(subList.iterator(), separator);
4488    }
4489
4490    /**
4491     * <p>Joins the elements of the provided {@code List} into a single String
4492     * containing the provided list of elements.</p>
4493     *
4494     * <p>No delimiter is added before or after the list.
4495     * Null objects or empty strings within the array are represented by
4496     * empty strings.</p>
4497     *
4498     * <pre>
4499     * StringUtils.join(null, *)               = null
4500     * StringUtils.join([], *)                 = ""
4501     * StringUtils.join([null], *)             = ""
4502     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4503     * StringUtils.join(["a", "b", "c"], null) = "abc"
4504     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4505     * </pre>
4506     *
4507     * @param list  the {@code List} of values to join together, may be null
4508     * @param separator  the separator character to use
4509     * @param startIndex the first index to start joining from.  It is
4510     * an error to pass in a start index past the end of the list
4511     * @param endIndex the index to stop joining from (exclusive). It is
4512     * an error to pass in an end index past the end of the list
4513     * @return the joined String, {@code null} if null list input
4514     * @since 3.8
4515     */
4516    public static String join(final List<?> list, final String separator, final int startIndex, final int endIndex) {
4517        if (list == null) {
4518            return null;
4519        }
4520        final int noOfItems = endIndex - startIndex;
4521        if (noOfItems <= 0) {
4522            return EMPTY;
4523        }
4524        final List<?> subList = list.subList(startIndex, endIndex);
4525        return join(subList.iterator(), separator);
4526    }
4527
4528
4529    /**
4530     * <p>
4531     * Joins the elements of the provided array into a single String containing the provided list of elements.
4532     * </p>
4533     *
4534     * <p>
4535     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4536     * by empty strings.
4537     * </p>
4538     *
4539     * <pre>
4540     * StringUtils.join(null, *)               = null
4541     * StringUtils.join([], *)                 = ""
4542     * StringUtils.join([null], *)             = ""
4543     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4544     * StringUtils.join([1, 2, 3], null) = "123"
4545     * </pre>
4546     *
4547     * @param array
4548     *            the array of values to join together, may be null
4549     * @param separator
4550     *            the separator character to use
4551     * @return the joined String, {@code null} if null array input
4552     * @since 3.2
4553     */
4554    public static String join(final long[] array, final char separator) {
4555        if (array == null) {
4556            return null;
4557        }
4558        return join(array, separator, 0, array.length);
4559    }
4560
4561    /**
4562     * <p>
4563     * Joins the elements of the provided array into a single String containing the provided list of elements.
4564     * </p>
4565     *
4566     * <p>
4567     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4568     * by empty strings.
4569     * </p>
4570     *
4571     * <pre>
4572     * StringUtils.join(null, *)               = null
4573     * StringUtils.join([], *)                 = ""
4574     * StringUtils.join([null], *)             = ""
4575     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4576     * StringUtils.join([1, 2, 3], null) = "123"
4577     * </pre>
4578     *
4579     * @param array
4580     *            the array of values to join together, may be null
4581     * @param delimiter
4582     *            the separator character to use
4583     * @param startIndex
4584     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4585     *            array
4586     * @param endIndex
4587     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4588     *            the array
4589     * @return the joined String, {@code null} if null array input
4590     * @since 3.2
4591     */
4592    public static String join(final long[] array, final char delimiter, final int startIndex, final int endIndex) {
4593        if (array == null) {
4594            return null;
4595        }
4596        if (endIndex - startIndex <= 0) {
4597            return EMPTY;
4598        }
4599        final StringJoiner joiner = newStringJoiner(delimiter);
4600        for (int i = startIndex; i < endIndex; i++) {
4601            joiner.add(String.valueOf(array[i]));
4602        }
4603        return joiner.toString();
4604    }
4605
4606    /**
4607     * <p>Joins the elements of the provided array into a single String
4608     * containing the provided list of elements.</p>
4609     *
4610     * <p>No delimiter is added before or after the list.
4611     * Null objects or empty strings within the array are represented by
4612     * empty strings.</p>
4613     *
4614     * <pre>
4615     * StringUtils.join(null, *)               = null
4616     * StringUtils.join([], *)                 = ""
4617     * StringUtils.join([null], *)             = ""
4618     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4619     * StringUtils.join(["a", "b", "c"], null) = "abc"
4620     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4621     * </pre>
4622     *
4623     * @param array  the array of values to join together, may be null
4624     * @param delimiter  the separator character to use
4625     * @return the joined String, {@code null} if null array input
4626     * @since 2.0
4627     */
4628    public static String join(final Object[] array, final char delimiter) {
4629        if (array == null) {
4630            return null;
4631        }
4632        return join(array, delimiter, 0, array.length);
4633    }
4634
4635    /**
4636     * <p>Joins the elements of the provided array into a single String
4637     * containing the provided list of elements.</p>
4638     *
4639     * <p>No delimiter is added before or after the list.
4640     * Null objects or empty strings within the array are represented by
4641     * empty strings.</p>
4642     *
4643     * <pre>
4644     * StringUtils.join(null, *)               = null
4645     * StringUtils.join([], *)                 = ""
4646     * StringUtils.join([null], *)             = ""
4647     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4648     * StringUtils.join(["a", "b", "c"], null) = "abc"
4649     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4650     * </pre>
4651     *
4652     * @param array  the array of values to join together, may be null
4653     * @param delimiter  the separator character to use
4654     * @param startIndex the first index to start joining from.  It is
4655     * an error to pass in a start index past the end of the array
4656     * @param endIndex the index to stop joining from (exclusive). It is
4657     * an error to pass in an end index past the end of the array
4658     * @return the joined String, {@code null} if null array input
4659     * @since 2.0
4660     */
4661    public static String join(final Object[] array, final char delimiter, final int startIndex, final int endIndex) {
4662        if (array == null) {
4663            return null;
4664        }
4665        if (endIndex - startIndex <= 0) {
4666            return EMPTY;
4667        }
4668        final StringJoiner joiner = newStringJoiner(delimiter);
4669        for (int i = startIndex; i < endIndex; i++) {
4670            joiner.add(toStringOrEmpty(array[i]));
4671        }
4672        return joiner.toString();
4673    }
4674
4675    /**
4676     * <p>Joins the elements of the provided array into a single String
4677     * containing the provided list of elements.</p>
4678     *
4679     * <p>No delimiter is added before or after the list.
4680     * A {@code null} separator is the same as an empty String ("").
4681     * Null objects or empty strings within the array are represented by
4682     * empty strings.</p>
4683     *
4684     * <pre>
4685     * StringUtils.join(null, *)                = null
4686     * StringUtils.join([], *)                  = ""
4687     * StringUtils.join([null], *)              = ""
4688     * StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
4689     * StringUtils.join(["a", "b", "c"], null)  = "abc"
4690     * StringUtils.join(["a", "b", "c"], "")    = "abc"
4691     * StringUtils.join([null, "", "a"], ',')   = ",,a"
4692     * </pre>
4693     *
4694     * @param array  the array of values to join together, may be null
4695     * @param delimiter  the separator character to use, null treated as ""
4696     * @return the joined String, {@code null} if null array input
4697     */
4698    public static String join(final Object[] array, final String delimiter) {
4699        if (array == null) {
4700            return null;
4701        }
4702        return join(array, delimiter, 0, array.length);
4703    }
4704
4705    /**
4706     * <p>Joins the elements of the provided array into a single String
4707     * containing the provided list of elements.</p>
4708     *
4709     * <p>No delimiter is added before or after the list.
4710     * A {@code null} separator is the same as an empty String ("").
4711     * Null objects or empty strings within the array are represented by
4712     * empty strings.</p>
4713     *
4714     * <pre>
4715     * StringUtils.join(null, *, *, *)                = null
4716     * StringUtils.join([], *, *, *)                  = ""
4717     * StringUtils.join([null], *, *, *)              = ""
4718     * StringUtils.join(["a", "b", "c"], "--", 0, 3)  = "a--b--c"
4719     * StringUtils.join(["a", "b", "c"], "--", 1, 3)  = "b--c"
4720     * StringUtils.join(["a", "b", "c"], "--", 2, 3)  = "c"
4721     * StringUtils.join(["a", "b", "c"], "--", 2, 2)  = ""
4722     * StringUtils.join(["a", "b", "c"], null, 0, 3)  = "abc"
4723     * StringUtils.join(["a", "b", "c"], "", 0, 3)    = "abc"
4724     * StringUtils.join([null, "", "a"], ',', 0, 3)   = ",,a"
4725     * </pre>
4726     *
4727     * @param array  the array of values to join together, may be null
4728     * @param delimiter  the separator character to use, null treated as ""
4729     * @param startIndex the first index to start joining from.
4730     * @param endIndex the index to stop joining from (exclusive).
4731     * @return the joined String, {@code null} if null array input; or the empty string
4732     * if {@code endIndex - startIndex <= 0}. The number of joined entries is given by
4733     * {@code endIndex - startIndex}
4734     * @throws ArrayIndexOutOfBoundsException ife<br>
4735     * {@code startIndex < 0} or <br>
4736     * {@code startIndex >= array.length()} or <br>
4737     * {@code endIndex < 0} or <br>
4738     * {@code endIndex > array.length()}
4739     */
4740    public static String join(final Object[] array, final String delimiter, final int startIndex, final int endIndex) {
4741        if (array == null) {
4742            return null;
4743        }
4744        if (endIndex - startIndex <= 0) {
4745            return EMPTY;
4746        }
4747        final StringJoiner joiner = new StringJoiner(toStringOrEmpty(delimiter));
4748        for (int i = startIndex; i < endIndex; i++) {
4749            joiner.add(toStringOrEmpty(array[i]));
4750        }
4751        return joiner.toString();
4752    }
4753
4754    /**
4755     * <p>
4756     * Joins the elements of the provided array into a single String containing the provided list of elements.
4757     * </p>
4758     *
4759     * <p>
4760     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4761     * by empty strings.
4762     * </p>
4763     *
4764     * <pre>
4765     * StringUtils.join(null, *)               = null
4766     * StringUtils.join([], *)                 = ""
4767     * StringUtils.join([null], *)             = ""
4768     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4769     * StringUtils.join([1, 2, 3], null) = "123"
4770     * </pre>
4771     *
4772     * @param array
4773     *            the array of values to join together, may be null
4774     * @param delimiter
4775     *            the separator character to use
4776     * @return the joined String, {@code null} if null array input
4777     * @since 3.2
4778     */
4779    public static String join(final short[] array, final char delimiter) {
4780        if (array == null) {
4781            return null;
4782        }
4783        return join(array, delimiter, 0, array.length);
4784    }
4785
4786    /**
4787     * <p>
4788     * Joins the elements of the provided array into a single String containing the provided list of elements.
4789     * </p>
4790     *
4791     * <p>
4792     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4793     * by empty strings.
4794     * </p>
4795     *
4796     * <pre>
4797     * StringUtils.join(null, *)               = null
4798     * StringUtils.join([], *)                 = ""
4799     * StringUtils.join([null], *)             = ""
4800     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4801     * StringUtils.join([1, 2, 3], null) = "123"
4802     * </pre>
4803     *
4804     * @param array
4805     *            the array of values to join together, may be null
4806     * @param delimiter
4807     *            the separator character to use
4808     * @param startIndex
4809     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4810     *            array
4811     * @param endIndex
4812     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4813     *            the array
4814     * @return the joined String, {@code null} if null array input
4815     * @since 3.2
4816     */
4817    public static String join(final short[] array, final char delimiter, final int startIndex, final int endIndex) {
4818        if (array == null) {
4819            return null;
4820        }
4821        if (endIndex - startIndex <= 0) {
4822            return EMPTY;
4823        }
4824        final StringJoiner joiner = newStringJoiner(delimiter);
4825        for (int i = startIndex; i < endIndex; i++) {
4826            joiner.add(String.valueOf(array[i]));
4827        }
4828        return joiner.toString();
4829    }
4830
4831    /**
4832     * <p>Joins the elements of the provided array into a single String
4833     * containing the provided list of elements.</p>
4834     *
4835     * <p>No separator is added to the joined String.
4836     * Null objects or empty strings within the array are represented by
4837     * empty strings.</p>
4838     *
4839     * <pre>
4840     * StringUtils.join(null)            = null
4841     * StringUtils.join([])              = ""
4842     * StringUtils.join([null])          = ""
4843     * StringUtils.join(["a", "b", "c"]) = "abc"
4844     * StringUtils.join([null, "", "a"]) = "a"
4845     * </pre>
4846     *
4847     * @param <T> the specific type of values to join together
4848     * @param elements  the values to join together, may be null
4849     * @return the joined String, {@code null} if null array input
4850     * @since 2.0
4851     * @since 3.0 Changed signature to use varargs
4852     */
4853    @SafeVarargs
4854    public static <T> String join(final T... elements) {
4855        return join(elements, null);
4856    }
4857
4858    /**
4859     * <p>Joins the elements of the provided varargs into a
4860     * single String containing the provided elements.</p>
4861     *
4862     * <p>No delimiter is added before or after the list.
4863     * {@code null} elements and separator are treated as empty Strings ("").</p>
4864     *
4865     * <pre>
4866     * StringUtils.joinWith(",", {"a", "b"})        = "a,b"
4867     * StringUtils.joinWith(",", {"a", "b",""})     = "a,b,"
4868     * StringUtils.joinWith(",", {"a", null, "b"})  = "a,,b"
4869     * StringUtils.joinWith(null, {"a", "b"})       = "ab"
4870     * </pre>
4871     *
4872     * @param delimiter the separator character to use, null treated as ""
4873     * @param array the varargs providing the values to join together. {@code null} elements are treated as ""
4874     * @return the joined String.
4875     * @throws java.lang.IllegalArgumentException if a null varargs is provided
4876     * @since 3.5
4877     */
4878    public static String joinWith(final String delimiter, final Object... array) {
4879        if (array == null) {
4880            throw new IllegalArgumentException("Object varargs must not be null");
4881        }
4882        return join(array, delimiter);
4883    }
4884
4885    /**
4886     * <p>Finds the last index within a CharSequence, handling {@code null}.
4887     * This method uses {@link String#lastIndexOf(String)} if possible.</p>
4888     *
4889     * <p>A {@code null} CharSequence will return {@code -1}.</p>
4890     *
4891     * <pre>
4892     * StringUtils.lastIndexOf(null, *)          = -1
4893     * StringUtils.lastIndexOf(*, null)          = -1
4894     * StringUtils.lastIndexOf("", "")           = 0
4895     * StringUtils.lastIndexOf("aabaabaa", "a")  = 7
4896     * StringUtils.lastIndexOf("aabaabaa", "b")  = 5
4897     * StringUtils.lastIndexOf("aabaabaa", "ab") = 4
4898     * StringUtils.lastIndexOf("aabaabaa", "")   = 8
4899     * </pre>
4900     *
4901     * @param seq  the CharSequence to check, may be null
4902     * @param searchSeq  the CharSequence to find, may be null
4903     * @return the last index of the search String,
4904     *  -1 if no match or {@code null} string input
4905     * @since 2.0
4906     * @since 3.0 Changed signature from lastIndexOf(String, String) to lastIndexOf(CharSequence, CharSequence)
4907     */
4908    public static int lastIndexOf(final CharSequence seq, final CharSequence searchSeq) {
4909        if (seq == null) {
4910            return INDEX_NOT_FOUND;
4911        }
4912        return CharSequenceUtils.lastIndexOf(seq, searchSeq, seq.length());
4913    }
4914
4915    /**
4916     * <p>Finds the last index within a CharSequence, handling {@code null}.
4917     * This method uses {@link String#lastIndexOf(String, int)} if possible.</p>
4918     *
4919     * <p>A {@code null} CharSequence will return {@code -1}.
4920     * A negative start position returns {@code -1}.
4921     * An empty ("") search CharSequence always matches unless the start position is negative.
4922     * A start position greater than the string length searches the whole string.
4923     * The search starts at the startPos and works backwards; matches starting after the start
4924     * position are ignored.
4925     * </p>
4926     *
4927     * <pre>
4928     * StringUtils.lastIndexOf(null, *, *)          = -1
4929     * StringUtils.lastIndexOf(*, null, *)          = -1
4930     * StringUtils.lastIndexOf("aabaabaa", "a", 8)  = 7
4931     * StringUtils.lastIndexOf("aabaabaa", "b", 8)  = 5
4932     * StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
4933     * StringUtils.lastIndexOf("aabaabaa", "b", 9)  = 5
4934     * StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
4935     * StringUtils.lastIndexOf("aabaabaa", "a", 0)  = 0
4936     * StringUtils.lastIndexOf("aabaabaa", "b", 0)  = -1
4937     * StringUtils.lastIndexOf("aabaabaa", "b", 1)  = -1
4938     * StringUtils.lastIndexOf("aabaabaa", "b", 2)  = 2
4939     * StringUtils.lastIndexOf("aabaabaa", "ba", 2)  = 2
4940     * </pre>
4941     *
4942     * @param seq  the CharSequence to check, may be null
4943     * @param searchSeq  the CharSequence to find, may be null
4944     * @param startPos  the start position, negative treated as zero
4945     * @return the last index of the search CharSequence (always &le; startPos),
4946     *  -1 if no match or {@code null} string input
4947     * @since 2.0
4948     * @since 3.0 Changed signature from lastIndexOf(String, String, int) to lastIndexOf(CharSequence, CharSequence, int)
4949     */
4950    public static int lastIndexOf(final CharSequence seq, final CharSequence searchSeq, final int startPos) {
4951        return CharSequenceUtils.lastIndexOf(seq, searchSeq, startPos);
4952    }
4953
4954    /**
4955     * Returns the index within {@code seq} of the last occurrence of
4956     * the specified character. For values of {@code searchChar} in the
4957     * range from 0 to 0xFFFF (inclusive), the index (in Unicode code
4958     * units) returned is the largest value <i>k</i> such that:
4959     * <blockquote><pre>
4960     * this.charAt(<i>k</i>) == searchChar
4961     * </pre></blockquote>
4962     * is true. For other values of {@code searchChar}, it is the
4963     * largest value <i>k</i> such that:
4964     * <blockquote><pre>
4965     * this.codePointAt(<i>k</i>) == searchChar
4966     * </pre></blockquote>
4967     * is true.  In either case, if no such character occurs in this
4968     * string, then {@code -1} is returned. Furthermore, a {@code null} or empty ("")
4969     * {@code CharSequence} will return {@code -1}. The
4970     * {@code seq} {@code CharSequence} object is searched backwards
4971     * starting at the last character.
4972     *
4973     * <pre>
4974     * StringUtils.lastIndexOf(null, *)         = -1
4975     * StringUtils.lastIndexOf("", *)           = -1
4976     * StringUtils.lastIndexOf("aabaabaa", 'a') = 7
4977     * StringUtils.lastIndexOf("aabaabaa", 'b') = 5
4978     * </pre>
4979     *
4980     * @param seq  the {@code CharSequence} to check, may be null
4981     * @param searchChar  the character to find
4982     * @return the last index of the search character,
4983     *  -1 if no match or {@code null} string input
4984     * @since 2.0
4985     * @since 3.0 Changed signature from lastIndexOf(String, int) to lastIndexOf(CharSequence, int)
4986     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@code String}
4987     */
4988    public static int lastIndexOf(final CharSequence seq, final int searchChar) {
4989        if (isEmpty(seq)) {
4990            return INDEX_NOT_FOUND;
4991        }
4992        return CharSequenceUtils.lastIndexOf(seq, searchChar, seq.length());
4993    }
4994
4995    /**
4996     * Returns the index within {@code seq} of the last occurrence of
4997     * the specified character, searching backward starting at the
4998     * specified index. For values of {@code searchChar} in the range
4999     * from 0 to 0xFFFF (inclusive), the index returned is the largest
5000     * value <i>k</i> such that:
5001     * <blockquote><pre>
5002     * (this.charAt(<i>k</i>) == searchChar) &amp;&amp; (<i>k</i> &lt;= startPos)
5003     * </pre></blockquote>
5004     * is true. For other values of {@code searchChar}, it is the
5005     * largest value <i>k</i> such that:
5006     * <blockquote><pre>
5007     * (this.codePointAt(<i>k</i>) == searchChar) &amp;&amp; (<i>k</i> &lt;= startPos)
5008     * </pre></blockquote>
5009     * is true. In either case, if no such character occurs in {@code seq}
5010     * at or before position {@code startPos}, then
5011     * {@code -1} is returned. Furthermore, a {@code null} or empty ("")
5012     * {@code CharSequence} will return {@code -1}. A start position greater
5013     * than the string length searches the whole string.
5014     * The search starts at the {@code startPos} and works backwards;
5015     * matches starting after the start position are ignored.
5016     *
5017     * <p>All indices are specified in {@code char} values
5018     * (Unicode code units).
5019     *
5020     * <pre>
5021     * StringUtils.lastIndexOf(null, *, *)          = -1
5022     * StringUtils.lastIndexOf("", *,  *)           = -1
5023     * StringUtils.lastIndexOf("aabaabaa", 'b', 8)  = 5
5024     * StringUtils.lastIndexOf("aabaabaa", 'b', 4)  = 2
5025     * StringUtils.lastIndexOf("aabaabaa", 'b', 0)  = -1
5026     * StringUtils.lastIndexOf("aabaabaa", 'b', 9)  = 5
5027     * StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
5028     * StringUtils.lastIndexOf("aabaabaa", 'a', 0)  = 0
5029     * </pre>
5030     *
5031     * @param seq  the CharSequence to check, may be null
5032     * @param searchChar  the character to find
5033     * @param startPos  the start position
5034     * @return the last index of the search character (always &le; startPos),
5035     *  -1 if no match or {@code null} string input
5036     * @since 2.0
5037     * @since 3.0 Changed signature from lastIndexOf(String, int, int) to lastIndexOf(CharSequence, int, int)
5038     */
5039    public static int lastIndexOf(final CharSequence seq, final int searchChar, final int startPos) {
5040        if (isEmpty(seq)) {
5041            return INDEX_NOT_FOUND;
5042        }
5043        return CharSequenceUtils.lastIndexOf(seq, searchChar, startPos);
5044    }
5045
5046    /**
5047     * <p>Find the latest index of any substring in a set of potential substrings.</p>
5048     *
5049     * <p>A {@code null} CharSequence will return {@code -1}.
5050     * A {@code null} search array will return {@code -1}.
5051     * A {@code null} or zero length search array entry will be ignored,
5052     * but a search array containing "" will return the length of {@code str}
5053     * if {@code str} is not null. This method uses {@link String#indexOf(String)} if possible</p>
5054     *
5055     * <pre>
5056     * StringUtils.lastIndexOfAny(null, *)                    = -1
5057     * StringUtils.lastIndexOfAny(*, null)                    = -1
5058     * StringUtils.lastIndexOfAny(*, [])                      = -1
5059     * StringUtils.lastIndexOfAny(*, [null])                  = -1
5060     * StringUtils.lastIndexOfAny("zzabyycdxx", ["ab", "cd"]) = 6
5061     * StringUtils.lastIndexOfAny("zzabyycdxx", ["cd", "ab"]) = 6
5062     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", "op"]) = -1
5063     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", "op"]) = -1
5064     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", ""])   = 10
5065     * </pre>
5066     *
5067     * @param str  the CharSequence to check, may be null
5068     * @param searchStrs  the CharSequences to search for, may be null
5069     * @return the last index of any of the CharSequences, -1 if no match
5070     * @since 3.0 Changed signature from lastIndexOfAny(String, String[]) to lastIndexOfAny(CharSequence, CharSequence)
5071     */
5072    public static int lastIndexOfAny(final CharSequence str, final CharSequence... searchStrs) {
5073        if (str == null || searchStrs == null) {
5074            return INDEX_NOT_FOUND;
5075        }
5076        int ret = INDEX_NOT_FOUND;
5077        int tmp = 0;
5078        for (final CharSequence search : searchStrs) {
5079            if (search == null) {
5080                continue;
5081            }
5082            tmp = CharSequenceUtils.lastIndexOf(str, search, str.length());
5083            if (tmp > ret) {
5084                ret = tmp;
5085            }
5086        }
5087        return ret;
5088    }
5089
5090    /**
5091     * <p>Case in-sensitive find of the last index within a CharSequence.</p>
5092     *
5093     * <p>A {@code null} CharSequence will return {@code -1}.
5094     * A negative start position returns {@code -1}.
5095     * An empty ("") search CharSequence always matches unless the start position is negative.
5096     * A start position greater than the string length searches the whole string.</p>
5097     *
5098     * <pre>
5099     * StringUtils.lastIndexOfIgnoreCase(null, *)          = -1
5100     * StringUtils.lastIndexOfIgnoreCase(*, null)          = -1
5101     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A")  = 7
5102     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B")  = 5
5103     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB") = 4
5104     * </pre>
5105     *
5106     * @param str  the CharSequence to check, may be null
5107     * @param searchStr  the CharSequence to find, may be null
5108     * @return the first index of the search CharSequence,
5109     *  -1 if no match or {@code null} string input
5110     * @since 2.5
5111     * @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String) to lastIndexOfIgnoreCase(CharSequence, CharSequence)
5112     */
5113    public static int lastIndexOfIgnoreCase(final CharSequence str, final CharSequence searchStr) {
5114        if (str == null || searchStr == null) {
5115            return INDEX_NOT_FOUND;
5116        }
5117        return lastIndexOfIgnoreCase(str, searchStr, str.length());
5118    }
5119
5120    /**
5121     * <p>Case in-sensitive find of the last index within a CharSequence
5122     * from the specified position.</p>
5123     *
5124     * <p>A {@code null} CharSequence will return {@code -1}.
5125     * A negative start position returns {@code -1}.
5126     * An empty ("") search CharSequence always matches unless the start position is negative.
5127     * A start position greater than the string length searches the whole string.
5128     * The search starts at the startPos and works backwards; matches starting after the start
5129     * position are ignored.
5130     * </p>
5131     *
5132     * <pre>
5133     * StringUtils.lastIndexOfIgnoreCase(null, *, *)          = -1
5134     * StringUtils.lastIndexOfIgnoreCase(*, null, *)          = -1
5135     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 8)  = 7
5136     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 8)  = 5
5137     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB", 8) = 4
5138     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 9)  = 5
5139     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", -1) = -1
5140     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 0)  = 0
5141     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 0)  = -1
5142     * </pre>
5143     *
5144     * @param str  the CharSequence to check, may be null
5145     * @param searchStr  the CharSequence to find, may be null
5146     * @param startPos  the start position
5147     * @return the last index of the search CharSequence (always &le; startPos),
5148     *  -1 if no match or {@code null} input
5149     * @since 2.5
5150     * @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String, int) to lastIndexOfIgnoreCase(CharSequence, CharSequence, int)
5151     */
5152    public static int lastIndexOfIgnoreCase(final CharSequence str, final CharSequence searchStr, int startPos) {
5153        if (str == null || searchStr == null) {
5154            return INDEX_NOT_FOUND;
5155        }
5156        final int searchStrLength = searchStr.length();
5157        final int strLength = str.length();
5158        if (startPos > strLength - searchStrLength) {
5159            startPos = strLength - searchStrLength;
5160        }
5161        if (startPos < 0) {
5162            return INDEX_NOT_FOUND;
5163        }
5164        if (searchStrLength == 0) {
5165            return startPos;
5166        }
5167
5168        for (int i = startPos; i >= 0; i--) {
5169            if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStrLength)) {
5170                return i;
5171            }
5172        }
5173        return INDEX_NOT_FOUND;
5174    }
5175
5176    /**
5177     * <p>Finds the n-th last index within a String, handling {@code null}.
5178     * This method uses {@link String#lastIndexOf(String)}.</p>
5179     *
5180     * <p>A {@code null} String will return {@code -1}.</p>
5181     *
5182     * <pre>
5183     * StringUtils.lastOrdinalIndexOf(null, *, *)          = -1
5184     * StringUtils.lastOrdinalIndexOf(*, null, *)          = -1
5185     * StringUtils.lastOrdinalIndexOf("", "", *)           = 0
5186     * StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1)  = 7
5187     * StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2)  = 6
5188     * StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1)  = 5
5189     * StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2)  = 2
5190     * StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
5191     * StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
5192     * StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1)   = 8
5193     * StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2)   = 8
5194     * </pre>
5195     *
5196     * <p>Note that 'tail(CharSequence str, int n)' may be implemented as: </p>
5197     *
5198     * <pre>
5199     *   str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
5200     * </pre>
5201     *
5202     * @param str  the CharSequence to check, may be null
5203     * @param searchStr  the CharSequence to find, may be null
5204     * @param ordinal  the n-th last {@code searchStr} to find
5205     * @return the n-th last index of the search CharSequence,
5206     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5207     * @since 2.5
5208     * @since 3.0 Changed signature from lastOrdinalIndexOf(String, String, int) to lastOrdinalIndexOf(CharSequence, CharSequence, int)
5209     */
5210    public static int lastOrdinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal) {
5211        return ordinalIndexOf(str, searchStr, ordinal, true);
5212    }
5213
5214    /**
5215     * <p>Gets the leftmost {@code len} characters of a String.</p>
5216     *
5217     * <p>If {@code len} characters are not available, or the
5218     * String is {@code null}, the String will be returned without
5219     * an exception. An empty String is returned if len is negative.</p>
5220     *
5221     * <pre>
5222     * StringUtils.left(null, *)    = null
5223     * StringUtils.left(*, -ve)     = ""
5224     * StringUtils.left("", *)      = ""
5225     * StringUtils.left("abc", 0)   = ""
5226     * StringUtils.left("abc", 2)   = "ab"
5227     * StringUtils.left("abc", 4)   = "abc"
5228     * </pre>
5229     *
5230     * @param str  the String to get the leftmost characters from, may be null
5231     * @param len  the length of the required String
5232     * @return the leftmost characters, {@code null} if null String input
5233     */
5234    public static String left(final String str, final int len) {
5235        if (str == null) {
5236            return null;
5237        }
5238        if (len < 0) {
5239            return EMPTY;
5240        }
5241        if (str.length() <= len) {
5242            return str;
5243        }
5244        return str.substring(0, len);
5245    }
5246
5247    /**
5248     * <p>Left pad a String with spaces (' ').</p>
5249     *
5250     * <p>The String is padded to the size of {@code size}.</p>
5251     *
5252     * <pre>
5253     * StringUtils.leftPad(null, *)   = null
5254     * StringUtils.leftPad("", 3)     = "   "
5255     * StringUtils.leftPad("bat", 3)  = "bat"
5256     * StringUtils.leftPad("bat", 5)  = "  bat"
5257     * StringUtils.leftPad("bat", 1)  = "bat"
5258     * StringUtils.leftPad("bat", -1) = "bat"
5259     * </pre>
5260     *
5261     * @param str  the String to pad out, may be null
5262     * @param size  the size to pad to
5263     * @return left padded String or original String if no padding is necessary,
5264     *  {@code null} if null String input
5265     */
5266    public static String leftPad(final String str, final int size) {
5267        return leftPad(str, size, ' ');
5268    }
5269
5270    /**
5271     * <p>Left pad a String with a specified character.</p>
5272     *
5273     * <p>Pad to a size of {@code size}.</p>
5274     *
5275     * <pre>
5276     * StringUtils.leftPad(null, *, *)     = null
5277     * StringUtils.leftPad("", 3, 'z')     = "zzz"
5278     * StringUtils.leftPad("bat", 3, 'z')  = "bat"
5279     * StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
5280     * StringUtils.leftPad("bat", 1, 'z')  = "bat"
5281     * StringUtils.leftPad("bat", -1, 'z') = "bat"
5282     * </pre>
5283     *
5284     * @param str  the String to pad out, may be null
5285     * @param size  the size to pad to
5286     * @param padChar  the character to pad with
5287     * @return left padded String or original String if no padding is necessary,
5288     *  {@code null} if null String input
5289     * @since 2.0
5290     */
5291    public static String leftPad(final String str, final int size, final char padChar) {
5292        if (str == null) {
5293            return null;
5294        }
5295        final int pads = size - str.length();
5296        if (pads <= 0) {
5297            return str; // returns original String when possible
5298        }
5299        if (pads > PAD_LIMIT) {
5300            return leftPad(str, size, String.valueOf(padChar));
5301        }
5302        return repeat(padChar, pads).concat(str);
5303    }
5304
5305    /**
5306     * <p>Left pad a String with a specified String.</p>
5307     *
5308     * <p>Pad to a size of {@code size}.</p>
5309     *
5310     * <pre>
5311     * StringUtils.leftPad(null, *, *)      = null
5312     * StringUtils.leftPad("", 3, "z")      = "zzz"
5313     * StringUtils.leftPad("bat", 3, "yz")  = "bat"
5314     * StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
5315     * StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
5316     * StringUtils.leftPad("bat", 1, "yz")  = "bat"
5317     * StringUtils.leftPad("bat", -1, "yz") = "bat"
5318     * StringUtils.leftPad("bat", 5, null)  = "  bat"
5319     * StringUtils.leftPad("bat", 5, "")    = "  bat"
5320     * </pre>
5321     *
5322     * @param str  the String to pad out, may be null
5323     * @param size  the size to pad to
5324     * @param padStr  the String to pad with, null or empty treated as single space
5325     * @return left padded String or original String if no padding is necessary,
5326     *  {@code null} if null String input
5327     */
5328    public static String leftPad(final String str, final int size, String padStr) {
5329        if (str == null) {
5330            return null;
5331        }
5332        if (isEmpty(padStr)) {
5333            padStr = SPACE;
5334        }
5335        final int padLen = padStr.length();
5336        final int strLen = str.length();
5337        final int pads = size - strLen;
5338        if (pads <= 0) {
5339            return str; // returns original String when possible
5340        }
5341        if (padLen == 1 && pads <= PAD_LIMIT) {
5342            return leftPad(str, size, padStr.charAt(0));
5343        }
5344
5345        if (pads == padLen) {
5346            return padStr.concat(str);
5347        } else if (pads < padLen) {
5348            return padStr.substring(0, pads).concat(str);
5349        } else {
5350            final char[] padding = new char[pads];
5351            final char[] padChars = padStr.toCharArray();
5352            for (int i = 0; i < pads; i++) {
5353                padding[i] = padChars[i % padLen];
5354            }
5355            return new String(padding).concat(str);
5356        }
5357    }
5358
5359    /**
5360     * Gets a CharSequence length or {@code 0} if the CharSequence is
5361     * {@code null}.
5362     *
5363     * @param cs
5364     *            a CharSequence or {@code null}
5365     * @return CharSequence length or {@code 0} if the CharSequence is
5366     *         {@code null}.
5367     * @since 2.4
5368     * @since 3.0 Changed signature from length(String) to length(CharSequence)
5369     */
5370    public static int length(final CharSequence cs) {
5371        return cs == null ? 0 : cs.length();
5372    }
5373
5374    /**
5375     * <p>Converts a String to lower case as per {@link String#toLowerCase()}.</p>
5376     *
5377     * <p>A {@code null} input String returns {@code null}.</p>
5378     *
5379     * <pre>
5380     * StringUtils.lowerCase(null)  = null
5381     * StringUtils.lowerCase("")    = ""
5382     * StringUtils.lowerCase("aBc") = "abc"
5383     * </pre>
5384     *
5385     * <p><strong>Note:</strong> As described in the documentation for {@link String#toLowerCase()},
5386     * the result of this method is affected by the current locale.
5387     * For platform-independent case transformations, the method {@link #lowerCase(String, Locale)}
5388     * should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
5389     *
5390     * @param str  the String to lower case, may be null
5391     * @return the lower cased String, {@code null} if null String input
5392     */
5393    public static String lowerCase(final String str) {
5394        if (str == null) {
5395            return null;
5396        }
5397        return str.toLowerCase();
5398    }
5399
5400    /**
5401     * <p>Converts a String to lower case as per {@link String#toLowerCase(Locale)}.</p>
5402     *
5403     * <p>A {@code null} input String returns {@code null}.</p>
5404     *
5405     * <pre>
5406     * StringUtils.lowerCase(null, Locale.ENGLISH)  = null
5407     * StringUtils.lowerCase("", Locale.ENGLISH)    = ""
5408     * StringUtils.lowerCase("aBc", Locale.ENGLISH) = "abc"
5409     * </pre>
5410     *
5411     * @param str  the String to lower case, may be null
5412     * @param locale  the locale that defines the case transformation rules, must not be null
5413     * @return the lower cased String, {@code null} if null String input
5414     * @since 2.5
5415     */
5416    public static String lowerCase(final String str, final Locale locale) {
5417        if (str == null) {
5418            return null;
5419        }
5420        return str.toLowerCase(LocaleUtils.toLocale(locale));
5421    }
5422
5423    private static int[] matches(final CharSequence first, final CharSequence second) {
5424        final CharSequence max;
5425        final CharSequence min;
5426        if (first.length() > second.length()) {
5427            max = first;
5428            min = second;
5429        } else {
5430            max = second;
5431            min = first;
5432        }
5433        final int range = Math.max(max.length() / 2 - 1, 0);
5434        final int[] matchIndexes = new int[min.length()];
5435        Arrays.fill(matchIndexes, -1);
5436        final boolean[] matchFlags = new boolean[max.length()];
5437        int matches = 0;
5438        for (int mi = 0; mi < min.length(); mi++) {
5439            final char c1 = min.charAt(mi);
5440            for (int xi = Math.max(mi - range, 0), xn = Math.min(mi + range + 1, max.length()); xi < xn; xi++) {
5441                if (!matchFlags[xi] && c1 == max.charAt(xi)) {
5442                    matchIndexes[mi] = xi;
5443                    matchFlags[xi] = true;
5444                    matches++;
5445                    break;
5446                }
5447            }
5448        }
5449        final char[] ms1 = new char[matches];
5450        final char[] ms2 = new char[matches];
5451        for (int i = 0, si = 0; i < min.length(); i++) {
5452            if (matchIndexes[i] != -1) {
5453                ms1[si] = min.charAt(i);
5454                si++;
5455            }
5456        }
5457        for (int i = 0, si = 0; i < max.length(); i++) {
5458            if (matchFlags[i]) {
5459                ms2[si] = max.charAt(i);
5460                si++;
5461            }
5462        }
5463        int transpositions = 0;
5464        for (int mi = 0; mi < ms1.length; mi++) {
5465            if (ms1[mi] != ms2[mi]) {
5466                transpositions++;
5467            }
5468        }
5469        int prefix = 0;
5470        for (int mi = 0; mi < min.length(); mi++) {
5471            if (first.charAt(mi) == second.charAt(mi)) {
5472                prefix++;
5473            } else {
5474                break;
5475            }
5476        }
5477        return new int[] { matches, transpositions / 2, prefix, max.length() };
5478    }
5479
5480    /**
5481     * <p>Gets {@code len} characters from the middle of a String.</p>
5482     *
5483     * <p>If {@code len} characters are not available, the remainder
5484     * of the String will be returned without an exception. If the
5485     * String is {@code null}, {@code null} will be returned.
5486     * An empty String is returned if len is negative or exceeds the
5487     * length of {@code str}.</p>
5488     *
5489     * <pre>
5490     * StringUtils.mid(null, *, *)    = null
5491     * StringUtils.mid(*, *, -ve)     = ""
5492     * StringUtils.mid("", 0, *)      = ""
5493     * StringUtils.mid("abc", 0, 2)   = "ab"
5494     * StringUtils.mid("abc", 0, 4)   = "abc"
5495     * StringUtils.mid("abc", 2, 4)   = "c"
5496     * StringUtils.mid("abc", 4, 2)   = ""
5497     * StringUtils.mid("abc", -2, 2)  = "ab"
5498     * </pre>
5499     *
5500     * @param str  the String to get the characters from, may be null
5501     * @param pos  the position to start from, negative treated as zero
5502     * @param len  the length of the required String
5503     * @return the middle characters, {@code null} if null String input
5504     */
5505    public static String mid(final String str, int pos, final int len) {
5506        if (str == null) {
5507            return null;
5508        }
5509        if (len < 0 || pos > str.length()) {
5510            return EMPTY;
5511        }
5512        if (pos < 0) {
5513            pos = 0;
5514        }
5515        if (str.length() <= pos + len) {
5516            return str.substring(pos);
5517        }
5518        return str.substring(pos, pos + len);
5519    }
5520
5521    private static StringJoiner newStringJoiner(final char delimiter) {
5522        return new StringJoiner(String.valueOf(delimiter));
5523    }
5524
5525    /**
5526     * <p>
5527     * Similar to <a
5528     * href="http://www.w3.org/TR/xpath/#function-normalize-space">http://www.w3.org/TR/xpath/#function-normalize
5529     * -space</a>
5530     * </p>
5531     * <p>
5532     * The function returns the argument string with whitespace normalized by using
5533     * {@code {@link #trim(String)}} to remove leading and trailing whitespace
5534     * and then replacing sequences of whitespace characters by a single space.
5535     * </p>
5536     * In XML Whitespace characters are the same as those allowed by the <a
5537     * href="http://www.w3.org/TR/REC-xml/#NT-S">S</a> production, which is S ::= (#x20 | #x9 | #xD | #xA)+
5538     * <p>
5539     * Java's regexp pattern \s defines whitespace as [ \t\n\x0B\f\r]
5540     *
5541     * <p>For reference:</p>
5542     * <ul>
5543     * <li>\x0B = vertical tab</li>
5544     * <li>\f = #xC = form feed</li>
5545     * <li>#x20 = space</li>
5546     * <li>#x9 = \t</li>
5547     * <li>#xA = \n</li>
5548     * <li>#xD = \r</li>
5549     * </ul>
5550     *
5551     * <p>
5552     * The difference is that Java's whitespace includes vertical tab and form feed, which this functional will also
5553     * normalize. Additionally {@code {@link #trim(String)}} removes control characters (char &lt;= 32) from both
5554     * ends of this String.
5555     * </p>
5556     *
5557     * @see Pattern
5558     * @see #trim(String)
5559     * @see <a
5560     *      href="http://www.w3.org/TR/xpath/#function-normalize-space">http://www.w3.org/TR/xpath/#function-normalize-space</a>
5561     * @param str the source String to normalize whitespaces from, may be null
5562     * @return the modified string with whitespace normalized, {@code null} if null String input
5563     *
5564     * @since 3.0
5565     */
5566    public static String normalizeSpace(final String str) {
5567        // LANG-1020: Improved performance significantly by normalizing manually instead of using regex
5568        // See https://github.com/librucha/commons-lang-normalizespaces-benchmark for performance test
5569        if (isEmpty(str)) {
5570            return str;
5571        }
5572        final int size = str.length();
5573        final char[] newChars = new char[size];
5574        int count = 0;
5575        int whitespacesCount = 0;
5576        boolean startWhitespaces = true;
5577        for (int i = 0; i < size; i++) {
5578            final char actualChar = str.charAt(i);
5579            final boolean isWhitespace = Character.isWhitespace(actualChar);
5580            if (isWhitespace) {
5581                if (whitespacesCount == 0 && !startWhitespaces) {
5582                    newChars[count++] = SPACE.charAt(0);
5583                }
5584                whitespacesCount++;
5585            } else {
5586                startWhitespaces = false;
5587                newChars[count++] = (actualChar == 160 ? 32 : actualChar);
5588                whitespacesCount = 0;
5589            }
5590        }
5591        if (startWhitespaces) {
5592            return EMPTY;
5593        }
5594        return new String(newChars, 0, count - (whitespacesCount > 0 ? 1 : 0)).trim();
5595    }
5596
5597    /**
5598     * <p>Finds the n-th index within a CharSequence, handling {@code null}.
5599     * This method uses {@link String#indexOf(String)} if possible.</p>
5600     * <p><b>Note:</b> The code starts looking for a match at the start of the target,
5601     * incrementing the starting index by one after each successful match
5602     * (unless {@code searchStr} is an empty string in which case the position
5603     * is never incremented and {@code 0} is returned immediately).
5604     * This means that matches may overlap.</p>
5605     * <p>A {@code null} CharSequence will return {@code -1}.</p>
5606     *
5607     * <pre>
5608     * StringUtils.ordinalIndexOf(null, *, *)          = -1
5609     * StringUtils.ordinalIndexOf(*, null, *)          = -1
5610     * StringUtils.ordinalIndexOf("", "", *)           = 0
5611     * StringUtils.ordinalIndexOf("aabaabaa", "a", 1)  = 0
5612     * StringUtils.ordinalIndexOf("aabaabaa", "a", 2)  = 1
5613     * StringUtils.ordinalIndexOf("aabaabaa", "b", 1)  = 2
5614     * StringUtils.ordinalIndexOf("aabaabaa", "b", 2)  = 5
5615     * StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
5616     * StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
5617     * StringUtils.ordinalIndexOf("aabaabaa", "", 1)   = 0
5618     * StringUtils.ordinalIndexOf("aabaabaa", "", 2)   = 0
5619     * </pre>
5620     *
5621     * <p>Matches may overlap:</p>
5622     * <pre>
5623     * StringUtils.ordinalIndexOf("ababab", "aba", 1)   = 0
5624     * StringUtils.ordinalIndexOf("ababab", "aba", 2)   = 2
5625     * StringUtils.ordinalIndexOf("ababab", "aba", 3)   = -1
5626     *
5627     * StringUtils.ordinalIndexOf("abababab", "abab", 1) = 0
5628     * StringUtils.ordinalIndexOf("abababab", "abab", 2) = 2
5629     * StringUtils.ordinalIndexOf("abababab", "abab", 3) = 4
5630     * StringUtils.ordinalIndexOf("abababab", "abab", 4) = -1
5631     * </pre>
5632     *
5633     * <p>Note that 'head(CharSequence str, int n)' may be implemented as: </p>
5634     *
5635     * <pre>
5636     *   str.substring(0, lastOrdinalIndexOf(str, "\n", n))
5637     * </pre>
5638     *
5639     * @param str  the CharSequence to check, may be null
5640     * @param searchStr  the CharSequence to find, may be null
5641     * @param ordinal  the n-th {@code searchStr} to find
5642     * @return the n-th index of the search CharSequence,
5643     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5644     * @since 2.1
5645     * @since 3.0 Changed signature from ordinalIndexOf(String, String, int) to ordinalIndexOf(CharSequence, CharSequence, int)
5646     */
5647    public static int ordinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal) {
5648        return ordinalIndexOf(str, searchStr, ordinal, false);
5649    }
5650
5651    /**
5652     * <p>Finds the n-th index within a String, handling {@code null}.
5653     * This method uses {@link String#indexOf(String)} if possible.</p>
5654     * <p>Note that matches may overlap<p>
5655     *
5656     * <p>A {@code null} CharSequence will return {@code -1}.</p>
5657     *
5658     * @param str  the CharSequence to check, may be null
5659     * @param searchStr  the CharSequence to find, may be null
5660     * @param ordinal  the n-th {@code searchStr} to find, overlapping matches are allowed.
5661     * @param lastIndex true if lastOrdinalIndexOf() otherwise false if ordinalIndexOf()
5662     * @return the n-th index of the search CharSequence,
5663     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5664     */
5665    // Shared code between ordinalIndexOf(String, String, int) and lastOrdinalIndexOf(String, String, int)
5666    private static int ordinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal, final boolean lastIndex) {
5667        if (str == null || searchStr == null || ordinal <= 0) {
5668            return INDEX_NOT_FOUND;
5669        }
5670        if (searchStr.length() == 0) {
5671            return lastIndex ? str.length() : 0;
5672        }
5673        int found = 0;
5674        // set the initial index beyond the end of the string
5675        // this is to allow for the initial index decrement/increment
5676        int index = lastIndex ? str.length() : INDEX_NOT_FOUND;
5677        do {
5678            if (lastIndex) {
5679                index = CharSequenceUtils.lastIndexOf(str, searchStr, index - 1); // step backwards thru string
5680            } else {
5681                index = CharSequenceUtils.indexOf(str, searchStr, index + 1); // step forwards through string
5682            }
5683            if (index < 0) {
5684                return index;
5685            }
5686            found++;
5687        } while (found < ordinal);
5688        return index;
5689    }
5690
5691    /**
5692     * <p>Overlays part of a String with another String.</p>
5693     *
5694     * <p>A {@code null} string input returns {@code null}.
5695     * A negative index is treated as zero.
5696     * An index greater than the string length is treated as the string length.
5697     * The start index is always the smaller of the two indices.</p>
5698     *
5699     * <pre>
5700     * StringUtils.overlay(null, *, *, *)            = null
5701     * StringUtils.overlay("", "abc", 0, 0)          = "abc"
5702     * StringUtils.overlay("abcdef", null, 2, 4)     = "abef"
5703     * StringUtils.overlay("abcdef", "", 2, 4)       = "abef"
5704     * StringUtils.overlay("abcdef", "", 4, 2)       = "abef"
5705     * StringUtils.overlay("abcdef", "zzzz", 2, 4)   = "abzzzzef"
5706     * StringUtils.overlay("abcdef", "zzzz", 4, 2)   = "abzzzzef"
5707     * StringUtils.overlay("abcdef", "zzzz", -1, 4)  = "zzzzef"
5708     * StringUtils.overlay("abcdef", "zzzz", 2, 8)   = "abzzzz"
5709     * StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
5710     * StringUtils.overlay("abcdef", "zzzz", 8, 10)  = "abcdefzzzz"
5711     * </pre>
5712     *
5713     * @param str  the String to do overlaying in, may be null
5714     * @param overlay  the String to overlay, may be null
5715     * @param start  the position to start overlaying at
5716     * @param end  the position to stop overlaying before
5717     * @return overlayed String, {@code null} if null String input
5718     * @since 2.0
5719     */
5720    public static String overlay(final String str, String overlay, int start, int end) {
5721        if (str == null) {
5722            return null;
5723        }
5724        if (overlay == null) {
5725            overlay = EMPTY;
5726        }
5727        final int len = str.length();
5728        if (start < 0) {
5729            start = 0;
5730        }
5731        if (start > len) {
5732            start = len;
5733        }
5734        if (end < 0) {
5735            end = 0;
5736        }
5737        if (end > len) {
5738            end = len;
5739        }
5740        if (start > end) {
5741            final int temp = start;
5742            start = end;
5743            end = temp;
5744        }
5745        return str.substring(0, start) +
5746            overlay +
5747            str.substring(end);
5748    }
5749
5750    /**
5751     * Prepends the prefix to the start of the string if the string does not
5752     * already start with any of the prefixes.
5753     *
5754     * @param str The string.
5755     * @param prefix The prefix to prepend to the start of the string.
5756     * @param ignoreCase Indicates whether the compare should ignore case.
5757     * @param prefixes Additional prefixes that are valid (optional).
5758     *
5759     * @return A new String if prefix was prepended, the same string otherwise.
5760     */
5761    private static String prependIfMissing(final String str, final CharSequence prefix, final boolean ignoreCase, final CharSequence... prefixes) {
5762        if (str == null || isEmpty(prefix) || startsWith(str, prefix, ignoreCase)) {
5763            return str;
5764        }
5765        if (ArrayUtils.isNotEmpty(prefixes)) {
5766            for (final CharSequence p : prefixes) {
5767                if (startsWith(str, p, ignoreCase)) {
5768                    return str;
5769                }
5770            }
5771        }
5772        return prefix.toString() + str;
5773    }
5774
5775    /**
5776     * Prepends the prefix to the start of the string if the string does not
5777     * already start with any of the prefixes.
5778     *
5779     * <pre>
5780     * StringUtils.prependIfMissing(null, null) = null
5781     * StringUtils.prependIfMissing("abc", null) = "abc"
5782     * StringUtils.prependIfMissing("", "xyz") = "xyz"
5783     * StringUtils.prependIfMissing("abc", "xyz") = "xyzabc"
5784     * StringUtils.prependIfMissing("xyzabc", "xyz") = "xyzabc"
5785     * StringUtils.prependIfMissing("XYZabc", "xyz") = "xyzXYZabc"
5786     * </pre>
5787     * <p>With additional prefixes,</p>
5788     * <pre>
5789     * StringUtils.prependIfMissing(null, null, null) = null
5790     * StringUtils.prependIfMissing("abc", null, null) = "abc"
5791     * StringUtils.prependIfMissing("", "xyz", null) = "xyz"
5792     * StringUtils.prependIfMissing("abc", "xyz", new CharSequence[]{null}) = "xyzabc"
5793     * StringUtils.prependIfMissing("abc", "xyz", "") = "abc"
5794     * StringUtils.prependIfMissing("abc", "xyz", "mno") = "xyzabc"
5795     * StringUtils.prependIfMissing("xyzabc", "xyz", "mno") = "xyzabc"
5796     * StringUtils.prependIfMissing("mnoabc", "xyz", "mno") = "mnoabc"
5797     * StringUtils.prependIfMissing("XYZabc", "xyz", "mno") = "xyzXYZabc"
5798     * StringUtils.prependIfMissing("MNOabc", "xyz", "mno") = "xyzMNOabc"
5799     * </pre>
5800     *
5801     * @param str The string.
5802     * @param prefix The prefix to prepend to the start of the string.
5803     * @param prefixes Additional prefixes that are valid.
5804     *
5805     * @return A new String if prefix was prepended, the same string otherwise.
5806     *
5807     * @since 3.2
5808     */
5809    public static String prependIfMissing(final String str, final CharSequence prefix, final CharSequence... prefixes) {
5810        return prependIfMissing(str, prefix, false, prefixes);
5811    }
5812
5813    /**
5814     * Prepends the prefix to the start of the string if the string does not
5815     * already start, case insensitive, with any of the prefixes.
5816     *
5817     * <pre>
5818     * StringUtils.prependIfMissingIgnoreCase(null, null) = null
5819     * StringUtils.prependIfMissingIgnoreCase("abc", null) = "abc"
5820     * StringUtils.prependIfMissingIgnoreCase("", "xyz") = "xyz"
5821     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz") = "xyzabc"
5822     * StringUtils.prependIfMissingIgnoreCase("xyzabc", "xyz") = "xyzabc"
5823     * StringUtils.prependIfMissingIgnoreCase("XYZabc", "xyz") = "XYZabc"
5824     * </pre>
5825     * <p>With additional prefixes,</p>
5826     * <pre>
5827     * StringUtils.prependIfMissingIgnoreCase(null, null, null) = null
5828     * StringUtils.prependIfMissingIgnoreCase("abc", null, null) = "abc"
5829     * StringUtils.prependIfMissingIgnoreCase("", "xyz", null) = "xyz"
5830     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", new CharSequence[]{null}) = "xyzabc"
5831     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", "") = "abc"
5832     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", "mno") = "xyzabc"
5833     * StringUtils.prependIfMissingIgnoreCase("xyzabc", "xyz", "mno") = "xyzabc"
5834     * StringUtils.prependIfMissingIgnoreCase("mnoabc", "xyz", "mno") = "mnoabc"
5835     * StringUtils.prependIfMissingIgnoreCase("XYZabc", "xyz", "mno") = "XYZabc"
5836     * StringUtils.prependIfMissingIgnoreCase("MNOabc", "xyz", "mno") = "MNOabc"
5837     * </pre>
5838     *
5839     * @param str The string.
5840     * @param prefix The prefix to prepend to the start of the string.
5841     * @param prefixes Additional prefixes that are valid (optional).
5842     *
5843     * @return A new String if prefix was prepended, the same string otherwise.
5844     *
5845     * @since 3.2
5846     */
5847    public static String prependIfMissingIgnoreCase(final String str, final CharSequence prefix, final CharSequence... prefixes) {
5848        return prependIfMissing(str, prefix, true, prefixes);
5849    }
5850
5851    /**
5852     * <p>Removes all occurrences of a character from within the source string.</p>
5853     *
5854     * <p>A {@code null} source string will return {@code null}.
5855     * An empty ("") source string will return the empty string.</p>
5856     *
5857     * <pre>
5858     * StringUtils.remove(null, *)       = null
5859     * StringUtils.remove("", *)         = ""
5860     * StringUtils.remove("queued", 'u') = "qeed"
5861     * StringUtils.remove("queued", 'z') = "queued"
5862     * </pre>
5863     *
5864     * @param str  the source String to search, may be null
5865     * @param remove  the char to search for and remove, may be null
5866     * @return the substring with the char removed if found,
5867     *  {@code null} if null String input
5868     * @since 2.1
5869     */
5870    public static String remove(final String str, final char remove) {
5871        if (isEmpty(str) || str.indexOf(remove) == INDEX_NOT_FOUND) {
5872            return str;
5873        }
5874        final char[] chars = str.toCharArray();
5875        int pos = 0;
5876        for (int i = 0; i < chars.length; i++) {
5877            if (chars[i] != remove) {
5878                chars[pos++] = chars[i];
5879            }
5880        }
5881        return new String(chars, 0, pos);
5882    }
5883
5884    /**
5885     * <p>Removes all occurrences of a substring from within the source string.</p>
5886     *
5887     * <p>A {@code null} source string will return {@code null}.
5888     * An empty ("") source string will return the empty string.
5889     * A {@code null} remove string will return the source string.
5890     * An empty ("") remove string will return the source string.</p>
5891     *
5892     * <pre>
5893     * StringUtils.remove(null, *)        = null
5894     * StringUtils.remove("", *)          = ""
5895     * StringUtils.remove(*, null)        = *
5896     * StringUtils.remove(*, "")          = *
5897     * StringUtils.remove("queued", "ue") = "qd"
5898     * StringUtils.remove("queued", "zz") = "queued"
5899     * </pre>
5900     *
5901     * @param str  the source String to search, may be null
5902     * @param remove  the String to search for and remove, may be null
5903     * @return the substring with the string removed if found,
5904     *  {@code null} if null String input
5905     * @since 2.1
5906     */
5907    public static String remove(final String str, final String remove) {
5908        if (isEmpty(str) || isEmpty(remove)) {
5909            return str;
5910        }
5911        return replace(str, remove, EMPTY, -1);
5912    }
5913
5914    /**
5915     * <p>Removes each substring of the text String that matches the given regular expression.</p>
5916     *
5917     * This method is a {@code null} safe equivalent to:
5918     * <ul>
5919     *  <li>{@code text.replaceAll(regex, StringUtils.EMPTY)}</li>
5920     *  <li>{@code Pattern.compile(regex).matcher(text).replaceAll(StringUtils.EMPTY)}</li>
5921     * </ul>
5922     *
5923     * <p>A {@code null} reference passed to this method is a no-op.</p>
5924     *
5925     * <p>Unlike in the {@link #removePattern(String, String)} method, the {@link Pattern#DOTALL} option
5926     * is NOT automatically added.
5927     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
5928     * DOTALL is also known as single-line mode in Perl.</p>
5929     *
5930     * <pre>
5931     * StringUtils.removeAll(null, *)      = null
5932     * StringUtils.removeAll("any", (String) null)  = "any"
5933     * StringUtils.removeAll("any", "")    = "any"
5934     * StringUtils.removeAll("any", ".*")  = ""
5935     * StringUtils.removeAll("any", ".+")  = ""
5936     * StringUtils.removeAll("abc", ".?")  = ""
5937     * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;")      = "A\nB"
5938     * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", "(?s)&lt;.*&gt;")  = "AB"
5939     * StringUtils.removeAll("ABCabc123abc", "[a-z]")     = "ABC123"
5940     * </pre>
5941     *
5942     * @param text  text to remove from, may be null
5943     * @param regex  the regular expression to which this string is to be matched
5944     * @return  the text with any removes processed,
5945     *              {@code null} if null String input
5946     *
5947     * @throws  java.util.regex.PatternSyntaxException
5948     *              if the regular expression's syntax is invalid
5949     *
5950     * @see #replaceAll(String, String, String)
5951     * @see #removePattern(String, String)
5952     * @see String#replaceAll(String, String)
5953     * @see java.util.regex.Pattern
5954     * @see java.util.regex.Pattern#DOTALL
5955     * @since 3.5
5956     *
5957     * @deprecated Moved to RegExUtils.
5958     */
5959    @Deprecated
5960    public static String removeAll(final String text, final String regex) {
5961        return RegExUtils.removeAll(text, regex);
5962    }
5963
5964    /**
5965     * <p>Removes a substring only if it is at the end of a source string,
5966     * otherwise returns the source string.</p>
5967     *
5968     * <p>A {@code null} source string will return {@code null}.
5969     * An empty ("") source string will return the empty string.
5970     * A {@code null} search string will return the source string.</p>
5971     *
5972     * <pre>
5973     * StringUtils.removeEnd(null, *)      = null
5974     * StringUtils.removeEnd("", *)        = ""
5975     * StringUtils.removeEnd(*, null)      = *
5976     * StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
5977     * StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
5978     * StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
5979     * StringUtils.removeEnd("abc", "")    = "abc"
5980     * </pre>
5981     *
5982     * @param str  the source String to search, may be null
5983     * @param remove  the String to search for and remove, may be null
5984     * @return the substring with the string removed if found,
5985     *  {@code null} if null String input
5986     * @since 2.1
5987     */
5988    public static String removeEnd(final String str, final String remove) {
5989        if (isEmpty(str) || isEmpty(remove)) {
5990            return str;
5991        }
5992        if (str.endsWith(remove)) {
5993            return str.substring(0, str.length() - remove.length());
5994        }
5995        return str;
5996    }
5997
5998    /**
5999     * <p>Case insensitive removal of a substring if it is at the end of a source string,
6000     * otherwise returns the source string.</p>
6001     *
6002     * <p>A {@code null} source string will return {@code null}.
6003     * An empty ("") source string will return the empty string.
6004     * A {@code null} search string will return the source string.</p>
6005     *
6006     * <pre>
6007     * StringUtils.removeEndIgnoreCase(null, *)      = null
6008     * StringUtils.removeEndIgnoreCase("", *)        = ""
6009     * StringUtils.removeEndIgnoreCase(*, null)      = *
6010     * StringUtils.removeEndIgnoreCase("www.domain.com", ".com.")  = "www.domain.com"
6011     * StringUtils.removeEndIgnoreCase("www.domain.com", ".com")   = "www.domain"
6012     * StringUtils.removeEndIgnoreCase("www.domain.com", "domain") = "www.domain.com"
6013     * StringUtils.removeEndIgnoreCase("abc", "")    = "abc"
6014     * StringUtils.removeEndIgnoreCase("www.domain.com", ".COM") = "www.domain")
6015     * StringUtils.removeEndIgnoreCase("www.domain.COM", ".com") = "www.domain")
6016     * </pre>
6017     *
6018     * @param str  the source String to search, may be null
6019     * @param remove  the String to search for (case insensitive) and remove, may be null
6020     * @return the substring with the string removed if found,
6021     *  {@code null} if null String input
6022     * @since 2.4
6023     */
6024    public static String removeEndIgnoreCase(final String str, final String remove) {
6025        if (isEmpty(str) || isEmpty(remove)) {
6026            return str;
6027        }
6028        if (endsWithIgnoreCase(str, remove)) {
6029            return str.substring(0, str.length() - remove.length());
6030        }
6031        return str;
6032    }
6033
6034    /**
6035     * <p>Removes the first substring of the text string that matches the given regular expression.</p>
6036     *
6037     * This method is a {@code null} safe equivalent to:
6038     * <ul>
6039     *  <li>{@code text.replaceFirst(regex, StringUtils.EMPTY)}</li>
6040     *  <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(StringUtils.EMPTY)}</li>
6041     * </ul>
6042     *
6043     * <p>A {@code null} reference passed to this method is a no-op.</p>
6044     *
6045     * <p>The {@link Pattern#DOTALL} option is NOT automatically added.
6046     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
6047     * DOTALL is also known as single-line mode in Perl.</p>
6048     *
6049     * <pre>
6050     * StringUtils.removeFirst(null, *)      = null
6051     * StringUtils.removeFirst("any", (String) null)  = "any"
6052     * StringUtils.removeFirst("any", "")    = "any"
6053     * StringUtils.removeFirst("any", ".*")  = ""
6054     * StringUtils.removeFirst("any", ".+")  = ""
6055     * StringUtils.removeFirst("abc", ".?")  = "bc"
6056     * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;")      = "A\n&lt;__&gt;B"
6057     * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", "(?s)&lt;.*&gt;")  = "AB"
6058     * StringUtils.removeFirst("ABCabc123", "[a-z]")          = "ABCbc123"
6059     * StringUtils.removeFirst("ABCabc123abc", "[a-z]+")      = "ABC123abc"
6060     * </pre>
6061     *
6062     * @param text  text to remove from, may be null
6063     * @param regex  the regular expression to which this string is to be matched
6064     * @return  the text with the first replacement processed,
6065     *              {@code null} if null String input
6066     *
6067     * @throws  java.util.regex.PatternSyntaxException
6068     *              if the regular expression's syntax is invalid
6069     *
6070     * @see #replaceFirst(String, String, String)
6071     * @see String#replaceFirst(String, String)
6072     * @see java.util.regex.Pattern
6073     * @see java.util.regex.Pattern#DOTALL
6074     * @since 3.5
6075     *
6076     * @deprecated Moved to RegExUtils.
6077     */
6078    @Deprecated
6079    public static String removeFirst(final String text, final String regex) {
6080        return replaceFirst(text, regex, EMPTY);
6081    }
6082
6083    /**
6084     * <p>
6085     * Case insensitive removal of all occurrences of a substring from within
6086     * the source string.
6087     * </p>
6088     *
6089     * <p>
6090     * A {@code null} source string will return {@code null}. An empty ("")
6091     * source string will return the empty string. A {@code null} remove string
6092     * will return the source string. An empty ("") remove string will return
6093     * the source string.
6094     * </p>
6095     *
6096     * <pre>
6097     * StringUtils.removeIgnoreCase(null, *)        = null
6098     * StringUtils.removeIgnoreCase("", *)          = ""
6099     * StringUtils.removeIgnoreCase(*, null)        = *
6100     * StringUtils.removeIgnoreCase(*, "")          = *
6101     * StringUtils.removeIgnoreCase("queued", "ue") = "qd"
6102     * StringUtils.removeIgnoreCase("queued", "zz") = "queued"
6103     * StringUtils.removeIgnoreCase("quEUed", "UE") = "qd"
6104     * StringUtils.removeIgnoreCase("queued", "zZ") = "queued"
6105     * </pre>
6106     *
6107     * @param str
6108     *            the source String to search, may be null
6109     * @param remove
6110     *            the String to search for (case insensitive) and remove, may be
6111     *            null
6112     * @return the substring with the string removed if found, {@code null} if
6113     *         null String input
6114     * @since 3.5
6115     */
6116    public static String removeIgnoreCase(final String str, final String remove) {
6117        return replaceIgnoreCase(str, remove, EMPTY, -1);
6118    }
6119
6120    /**
6121     * <p>Removes each substring of the source String that matches the given regular expression using the DOTALL option.
6122     * </p>
6123     *
6124     * This call is a {@code null} safe equivalent to:
6125     * <ul>
6126     * <li>{@code source.replaceAll(&quot;(?s)&quot; + regex, StringUtils.EMPTY)}</li>
6127     * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(source).replaceAll(StringUtils.EMPTY)}</li>
6128     * </ul>
6129     *
6130     * <p>A {@code null} reference passed to this method is a no-op.</p>
6131     *
6132     * <pre>
6133     * StringUtils.removePattern(null, *)       = null
6134     * StringUtils.removePattern("any", (String) null)   = "any"
6135     * StringUtils.removePattern("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;")  = "AB"
6136     * StringUtils.removePattern("ABCabc123", "[a-z]")    = "ABC123"
6137     * </pre>
6138     *
6139     * @param source
6140     *            the source string
6141     * @param regex
6142     *            the regular expression to which this string is to be matched
6143     * @return The resulting {@code String}
6144     * @see #replacePattern(String, String, String)
6145     * @see String#replaceAll(String, String)
6146     * @see Pattern#DOTALL
6147     * @since 3.2
6148     * @since 3.5 Changed {@code null} reference passed to this method is a no-op.
6149     *
6150     * @deprecated Moved to RegExUtils.
6151     */
6152    @Deprecated
6153    public static String removePattern(final String source, final String regex) {
6154        return RegExUtils.removePattern(source, regex);
6155    }
6156
6157    /**
6158     * <p>Removes a substring only if it is at the beginning of a source string,
6159     * otherwise returns the source string.</p>
6160     *
6161     * <p>A {@code null} source string will return {@code null}.
6162     * An empty ("") source string will return the empty string.
6163     * A {@code null} search string will return the source string.</p>
6164     *
6165     * <pre>
6166     * StringUtils.removeStart(null, *)      = null
6167     * StringUtils.removeStart("", *)        = ""
6168     * StringUtils.removeStart(*, null)      = *
6169     * StringUtils.removeStart("www.domain.com", "www.")   = "domain.com"
6170     * StringUtils.removeStart("domain.com", "www.")       = "domain.com"
6171     * StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
6172     * StringUtils.removeStart("abc", "")    = "abc"
6173     * </pre>
6174     *
6175     * @param str  the source String to search, may be null
6176     * @param remove  the String to search for and remove, may be null
6177     * @return the substring with the string removed if found,
6178     *  {@code null} if null String input
6179     * @since 2.1
6180     */
6181    public static String removeStart(final String str, final String remove) {
6182        if (isEmpty(str) || isEmpty(remove)) {
6183            return str;
6184        }
6185        if (str.startsWith(remove)) {
6186            return str.substring(remove.length());
6187        }
6188        return str;
6189    }
6190
6191    /**
6192     * <p>Case insensitive removal of a substring if it is at the beginning of a source string,
6193     * otherwise returns the source string.</p>
6194     *
6195     * <p>A {@code null} source string will return {@code null}.
6196     * An empty ("") source string will return the empty string.
6197     * A {@code null} search string will return the source string.</p>
6198     *
6199     * <pre>
6200     * StringUtils.removeStartIgnoreCase(null, *)      = null
6201     * StringUtils.removeStartIgnoreCase("", *)        = ""
6202     * StringUtils.removeStartIgnoreCase(*, null)      = *
6203     * StringUtils.removeStartIgnoreCase("www.domain.com", "www.")   = "domain.com"
6204     * StringUtils.removeStartIgnoreCase("www.domain.com", "WWW.")   = "domain.com"
6205     * StringUtils.removeStartIgnoreCase("domain.com", "www.")       = "domain.com"
6206     * StringUtils.removeStartIgnoreCase("www.domain.com", "domain") = "www.domain.com"
6207     * StringUtils.removeStartIgnoreCase("abc", "")    = "abc"
6208     * </pre>
6209     *
6210     * @param str  the source String to search, may be null
6211     * @param remove  the String to search for (case insensitive) and remove, may be null
6212     * @return the substring with the string removed if found,
6213     *  {@code null} if null String input
6214     * @since 2.4
6215     */
6216    public static String removeStartIgnoreCase(final String str, final String remove) {
6217        if (str != null && startsWithIgnoreCase(str, remove)) {
6218            return str.substring(length(remove));
6219        }
6220        return str;
6221    }
6222
6223    /**
6224     * <p>Returns padding using the specified delimiter repeated
6225     * to a given length.</p>
6226     *
6227     * <pre>
6228     * StringUtils.repeat('e', 0)  = ""
6229     * StringUtils.repeat('e', 3)  = "eee"
6230     * StringUtils.repeat('e', -2) = ""
6231     * </pre>
6232     *
6233     * <p>Note: this method does not support padding with
6234     * <a href="http://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
6235     * as they require a pair of {@code char}s to be represented.
6236     * If you are needing to support full I18N of your applications
6237     * consider using {@link #repeat(String, int)} instead.
6238     * </p>
6239     *
6240     * @param ch  character to repeat
6241     * @param repeat  number of times to repeat char, negative treated as zero
6242     * @return String with repeated character
6243     * @see #repeat(String, int)
6244     */
6245    public static String repeat(final char ch, final int repeat) {
6246        if (repeat <= 0) {
6247            return EMPTY;
6248        }
6249        final char[] buf = new char[repeat];
6250        Arrays.fill(buf, ch);
6251        return new String(buf);
6252    }
6253
6254    /**
6255     * <p>Repeat a String {@code repeat} times to form a
6256     * new String.</p>
6257     *
6258     * <pre>
6259     * StringUtils.repeat(null, 2) = null
6260     * StringUtils.repeat("", 0)   = ""
6261     * StringUtils.repeat("", 2)   = ""
6262     * StringUtils.repeat("a", 3)  = "aaa"
6263     * StringUtils.repeat("ab", 2) = "abab"
6264     * StringUtils.repeat("a", -2) = ""
6265     * </pre>
6266     *
6267     * @param str  the String to repeat, may be null
6268     * @param repeat  number of times to repeat str, negative treated as zero
6269     * @return a new String consisting of the original String repeated,
6270     *  {@code null} if null String input
6271     */
6272    public static String repeat(final String str, final int repeat) {
6273        // Performance tuned for 2.0 (JDK1.4)
6274        if (str == null) {
6275            return null;
6276        }
6277        if (repeat <= 0) {
6278            return EMPTY;
6279        }
6280        final int inputLength = str.length();
6281        if (repeat == 1 || inputLength == 0) {
6282            return str;
6283        }
6284        if (inputLength == 1 && repeat <= PAD_LIMIT) {
6285            return repeat(str.charAt(0), repeat);
6286        }
6287
6288        final int outputLength = inputLength * repeat;
6289        switch (inputLength) {
6290            case 1 :
6291                return repeat(str.charAt(0), repeat);
6292            case 2 :
6293                final char ch0 = str.charAt(0);
6294                final char ch1 = str.charAt(1);
6295                final char[] output2 = new char[outputLength];
6296                for (int i = repeat * 2 - 2; i >= 0; i--, i--) {
6297                    output2[i] = ch0;
6298                    output2[i + 1] = ch1;
6299                }
6300                return new String(output2);
6301            default :
6302                final StringBuilder buf = new StringBuilder(outputLength);
6303                for (int i = 0; i < repeat; i++) {
6304                    buf.append(str);
6305                }
6306                return buf.toString();
6307        }
6308    }
6309
6310    /**
6311     * <p>Repeat a String {@code repeat} times to form a
6312     * new String, with a String separator injected each time. </p>
6313     *
6314     * <pre>
6315     * StringUtils.repeat(null, null, 2) = null
6316     * StringUtils.repeat(null, "x", 2)  = null
6317     * StringUtils.repeat("", null, 0)   = ""
6318     * StringUtils.repeat("", "", 2)     = ""
6319     * StringUtils.repeat("", "x", 3)    = "xxx"
6320     * StringUtils.repeat("?", ", ", 3)  = "?, ?, ?"
6321     * </pre>
6322     *
6323     * @param str        the String to repeat, may be null
6324     * @param separator  the String to inject, may be null
6325     * @param repeat     number of times to repeat str, negative treated as zero
6326     * @return a new String consisting of the original String repeated,
6327     *  {@code null} if null String input
6328     * @since 2.5
6329     */
6330    public static String repeat(final String str, final String separator, final int repeat) {
6331        if (str == null || separator == null) {
6332            return repeat(str, repeat);
6333        }
6334        // given that repeat(String, int) is quite optimized, better to rely on it than try and splice this into it
6335        final String result = repeat(str + separator, repeat);
6336        return removeEnd(result, separator);
6337    }
6338
6339    /**
6340     * <p>Replaces all occurrences of a String within another String.</p>
6341     *
6342     * <p>A {@code null} reference passed to this method is a no-op.</p>
6343     *
6344     * <pre>
6345     * StringUtils.replace(null, *, *)        = null
6346     * StringUtils.replace("", *, *)          = ""
6347     * StringUtils.replace("any", null, *)    = "any"
6348     * StringUtils.replace("any", *, null)    = "any"
6349     * StringUtils.replace("any", "", *)      = "any"
6350     * StringUtils.replace("aba", "a", null)  = "aba"
6351     * StringUtils.replace("aba", "a", "")    = "b"
6352     * StringUtils.replace("aba", "a", "z")   = "zbz"
6353     * </pre>
6354     *
6355     * @see #replace(String text, String searchString, String replacement, int max)
6356     * @param text  text to search and replace in, may be null
6357     * @param searchString  the String to search for, may be null
6358     * @param replacement  the String to replace it with, may be null
6359     * @return the text with any replacements processed,
6360     *  {@code null} if null String input
6361     */
6362    public static String replace(final String text, final String searchString, final String replacement) {
6363        return replace(text, searchString, replacement, -1);
6364    }
6365
6366    /**
6367     * <p>Replaces a String with another String inside a larger String,
6368     * for the first {@code max} values of the search String.</p>
6369     *
6370     * <p>A {@code null} reference passed to this method is a no-op.</p>
6371     *
6372     * <pre>
6373     * StringUtils.replace(null, *, *, *)         = null
6374     * StringUtils.replace("", *, *, *)           = ""
6375     * StringUtils.replace("any", null, *, *)     = "any"
6376     * StringUtils.replace("any", *, null, *)     = "any"
6377     * StringUtils.replace("any", "", *, *)       = "any"
6378     * StringUtils.replace("any", *, *, 0)        = "any"
6379     * StringUtils.replace("abaa", "a", null, -1) = "abaa"
6380     * StringUtils.replace("abaa", "a", "", -1)   = "b"
6381     * StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
6382     * StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
6383     * StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
6384     * StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
6385     * </pre>
6386     *
6387     * @param text  text to search and replace in, may be null
6388     * @param searchString  the String to search for, may be null
6389     * @param replacement  the String to replace it with, may be null
6390     * @param max  maximum number of values to replace, or {@code -1} if no maximum
6391     * @return the text with any replacements processed,
6392     *  {@code null} if null String input
6393     */
6394    public static String replace(final String text, final String searchString, final String replacement, final int max) {
6395        return replace(text, searchString, replacement, max, false);
6396    }
6397
6398    /**
6399     * <p>Replaces a String with another String inside a larger String,
6400     * for the first {@code max} values of the search String,
6401     * case sensitively/insensitively based on {@code ignoreCase} value.</p>
6402     *
6403     * <p>A {@code null} reference passed to this method is a no-op.</p>
6404     *
6405     * <pre>
6406     * StringUtils.replace(null, *, *, *, false)         = null
6407     * StringUtils.replace("", *, *, *, false)           = ""
6408     * StringUtils.replace("any", null, *, *, false)     = "any"
6409     * StringUtils.replace("any", *, null, *, false)     = "any"
6410     * StringUtils.replace("any", "", *, *, false)       = "any"
6411     * StringUtils.replace("any", *, *, 0, false)        = "any"
6412     * StringUtils.replace("abaa", "a", null, -1, false) = "abaa"
6413     * StringUtils.replace("abaa", "a", "", -1, false)   = "b"
6414     * StringUtils.replace("abaa", "a", "z", 0, false)   = "abaa"
6415     * StringUtils.replace("abaa", "A", "z", 1, false)   = "abaa"
6416     * StringUtils.replace("abaa", "A", "z", 1, true)   = "zbaa"
6417     * StringUtils.replace("abAa", "a", "z", 2, true)   = "zbza"
6418     * StringUtils.replace("abAa", "a", "z", -1, true)  = "zbzz"
6419     * </pre>
6420     *
6421     * @param text  text to search and replace in, may be null
6422     * @param searchString  the String to search for (case insensitive), may be null
6423     * @param replacement  the String to replace it with, may be null
6424     * @param max  maximum number of values to replace, or {@code -1} if no maximum
6425     * @param ignoreCase if true replace is case insensitive, otherwise case sensitive
6426     * @return the text with any replacements processed,
6427     *  {@code null} if null String input
6428     */
6429     private static String replace(final String text, String searchString, final String replacement, int max, final boolean ignoreCase) {
6430         if (isEmpty(text) || isEmpty(searchString) || replacement == null || max == 0) {
6431             return text;
6432         }
6433         if (ignoreCase) {
6434             searchString = searchString.toLowerCase();
6435         }
6436         int start = 0;
6437         int end = ignoreCase ? indexOfIgnoreCase(text, searchString, start) : indexOf(text, searchString, start);
6438         if (end == INDEX_NOT_FOUND) {
6439             return text;
6440         }
6441         final int replLength = searchString.length();
6442         int increase = Math.max(replacement.length() - replLength, 0);
6443         increase *= max < 0 ? 16 : Math.min(max, 64);
6444         final StringBuilder buf = new StringBuilder(text.length() + increase);
6445         while (end != INDEX_NOT_FOUND) {
6446             buf.append(text, start, end).append(replacement);
6447             start = end + replLength;
6448             if (--max == 0) {
6449                 break;
6450             }
6451             end = ignoreCase ? indexOfIgnoreCase(text, searchString, start) : indexOf(text, searchString, start);
6452         }
6453         buf.append(text, start, text.length());
6454         return buf.toString();
6455     }
6456
6457    /**
6458     * <p>Replaces each substring of the text String that matches the given regular expression
6459     * with the given replacement.</p>
6460     *
6461     * This method is a {@code null} safe equivalent to:
6462     * <ul>
6463     *  <li>{@code text.replaceAll(regex, replacement)}</li>
6464     *  <li>{@code Pattern.compile(regex).matcher(text).replaceAll(replacement)}</li>
6465     * </ul>
6466     *
6467     * <p>A {@code null} reference passed to this method is a no-op.</p>
6468     *
6469     * <p>Unlike in the {@link #replacePattern(String, String, String)} method, the {@link Pattern#DOTALL} option
6470     * is NOT automatically added.
6471     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
6472     * DOTALL is also known as single-line mode in Perl.</p>
6473     *
6474     * <pre>
6475     * StringUtils.replaceAll(null, *, *)       = null
6476     * StringUtils.replaceAll("any", (String) null, *)   = "any"
6477     * StringUtils.replaceAll("any", *, null)   = "any"
6478     * StringUtils.replaceAll("", "", "zzz")    = "zzz"
6479     * StringUtils.replaceAll("", ".*", "zzz")  = "zzz"
6480     * StringUtils.replaceAll("", ".+", "zzz")  = ""
6481     * StringUtils.replaceAll("abc", "", "ZZ")  = "ZZaZZbZZcZZ"
6482     * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z")      = "z\nz"
6483     * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", "(?s)&lt;.*&gt;", "z")  = "z"
6484     * StringUtils.replaceAll("ABCabc123", "[a-z]", "_")       = "ABC___123"
6485     * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
6486     * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
6487     * StringUtils.replaceAll("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
6488     * </pre>
6489     *
6490     * @param text  text to search and replace in, may be null
6491     * @param regex  the regular expression to which this string is to be matched
6492     * @param replacement  the string to be substituted for each match
6493     * @return  the text with any replacements processed,
6494     *              {@code null} if null String input
6495     *
6496     * @throws  java.util.regex.PatternSyntaxException
6497     *              if the regular expression's syntax is invalid
6498     *
6499     * @see #replacePattern(String, String, String)
6500     * @see String#replaceAll(String, String)
6501     * @see java.util.regex.Pattern
6502     * @see java.util.regex.Pattern#DOTALL
6503     * @since 3.5
6504     *
6505     * @deprecated Moved to RegExUtils.
6506     */
6507    @Deprecated
6508    public static String replaceAll(final String text, final String regex, final String replacement) {
6509        return RegExUtils.replaceAll(text, regex, replacement);
6510    }
6511
6512    /**
6513     * <p>Replaces all occurrences of a character in a String with another.
6514     * This is a null-safe version of {@link String#replace(char, char)}.</p>
6515     *
6516     * <p>A {@code null} string input returns {@code null}.
6517     * An empty ("") string input returns an empty string.</p>
6518     *
6519     * <pre>
6520     * StringUtils.replaceChars(null, *, *)        = null
6521     * StringUtils.replaceChars("", *, *)          = ""
6522     * StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
6523     * StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
6524     * </pre>
6525     *
6526     * @param str  String to replace characters in, may be null
6527     * @param searchChar  the character to search for, may be null
6528     * @param replaceChar  the character to replace, may be null
6529     * @return modified String, {@code null} if null string input
6530     * @since 2.0
6531     */
6532    public static String replaceChars(final String str, final char searchChar, final char replaceChar) {
6533        if (str == null) {
6534            return null;
6535        }
6536        return str.replace(searchChar, replaceChar);
6537    }
6538
6539    /**
6540     * <p>Replaces multiple characters in a String in one go.
6541     * This method can also be used to delete characters.</p>
6542     *
6543     * <p>For example:<br>
6544     * {@code replaceChars(&quot;hello&quot;, &quot;ho&quot;, &quot;jy&quot;) = jelly}.</p>
6545     *
6546     * <p>A {@code null} string input returns {@code null}.
6547     * An empty ("") string input returns an empty string.
6548     * A null or empty set of search characters returns the input string.</p>
6549     *
6550     * <p>The length of the search characters should normally equal the length
6551     * of the replace characters.
6552     * If the search characters is longer, then the extra search characters
6553     * are deleted.
6554     * If the search characters is shorter, then the extra replace characters
6555     * are ignored.</p>
6556     *
6557     * <pre>
6558     * StringUtils.replaceChars(null, *, *)           = null
6559     * StringUtils.replaceChars("", *, *)             = ""
6560     * StringUtils.replaceChars("abc", null, *)       = "abc"
6561     * StringUtils.replaceChars("abc", "", *)         = "abc"
6562     * StringUtils.replaceChars("abc", "b", null)     = "ac"
6563     * StringUtils.replaceChars("abc", "b", "")       = "ac"
6564     * StringUtils.replaceChars("abcba", "bc", "yz")  = "ayzya"
6565     * StringUtils.replaceChars("abcba", "bc", "y")   = "ayya"
6566     * StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
6567     * </pre>
6568     *
6569     * @param str  String to replace characters in, may be null
6570     * @param searchChars  a set of characters to search for, may be null
6571     * @param replaceChars  a set of characters to replace, may be null
6572     * @return modified String, {@code null} if null string input
6573     * @since 2.0
6574     */
6575    public static String replaceChars(final String str, final String searchChars, String replaceChars) {
6576        if (isEmpty(str) || isEmpty(searchChars)) {
6577            return str;
6578        }
6579        if (replaceChars == null) {
6580            replaceChars = EMPTY;
6581        }
6582        boolean modified = false;
6583        final int replaceCharsLength = replaceChars.length();
6584        final int strLength = str.length();
6585        final StringBuilder buf = new StringBuilder(strLength);
6586        for (int i = 0; i < strLength; i++) {
6587            final char ch = str.charAt(i);
6588            final int index = searchChars.indexOf(ch);
6589            if (index >= 0) {
6590                modified = true;
6591                if (index < replaceCharsLength) {
6592                    buf.append(replaceChars.charAt(index));
6593                }
6594            } else {
6595                buf.append(ch);
6596            }
6597        }
6598        if (modified) {
6599            return buf.toString();
6600        }
6601        return str;
6602    }
6603
6604    /**
6605     * <p>
6606     * Replaces all occurrences of Strings within another String.
6607     * </p>
6608     *
6609     * <p>
6610     * A {@code null} reference passed to this method is a no-op, or if
6611     * any "search string" or "string to replace" is null, that replace will be
6612     * ignored. This will not repeat. For repeating replaces, call the
6613     * overloaded method.
6614     * </p>
6615     *
6616     * <pre>
6617     *  StringUtils.replaceEach(null, *, *)        = null
6618     *  StringUtils.replaceEach("", *, *)          = ""
6619     *  StringUtils.replaceEach("aba", null, null) = "aba"
6620     *  StringUtils.replaceEach("aba", new String[0], null) = "aba"
6621     *  StringUtils.replaceEach("aba", null, new String[0]) = "aba"
6622     *  StringUtils.replaceEach("aba", new String[]{"a"}, null)  = "aba"
6623     *  StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""})  = "b"
6624     *  StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"})  = "aba"
6625     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"})  = "wcte"
6626     *  (example of how it does not repeat)
6627     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"})  = "dcte"
6628     * </pre>
6629     *
6630     * @param text
6631     *            text to search and replace in, no-op if null
6632     * @param searchList
6633     *            the Strings to search for, no-op if null
6634     * @param replacementList
6635     *            the Strings to replace them with, no-op if null
6636     * @return the text with any replacements processed, {@code null} if
6637     *         null String input
6638     * @throws IllegalArgumentException
6639     *             if the lengths of the arrays are not the same (null is ok,
6640     *             and/or size 0)
6641     * @since 2.4
6642     */
6643    public static String replaceEach(final String text, final String[] searchList, final String[] replacementList) {
6644        return replaceEach(text, searchList, replacementList, false, 0);
6645    }
6646
6647    /**
6648     * <p>
6649     * Replace all occurrences of Strings within another String.
6650     * This is a private recursive helper method for {@link #replaceEachRepeatedly(String, String[], String[])} and
6651     * {@link #replaceEach(String, String[], String[])}
6652     * </p>
6653     *
6654     * <p>
6655     * A {@code null} reference passed to this method is a no-op, or if
6656     * any "search string" or "string to replace" is null, that replace will be
6657     * ignored.
6658     * </p>
6659     *
6660     * <pre>
6661     *  StringUtils.replaceEach(null, *, *, *, *) = null
6662     *  StringUtils.replaceEach("", *, *, *, *) = ""
6663     *  StringUtils.replaceEach("aba", null, null, *, *) = "aba"
6664     *  StringUtils.replaceEach("aba", new String[0], null, *, *) = "aba"
6665     *  StringUtils.replaceEach("aba", null, new String[0], *, *) = "aba"
6666     *  StringUtils.replaceEach("aba", new String[]{"a"}, null, *, *) = "aba"
6667     *  StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}, *, >=0) = "b"
6668     *  StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}, *, >=0) = "aba"
6669     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}, *, >=0) = "wcte"
6670     *  (example of how it repeats)
6671     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, false, >=0) = "dcte"
6672     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, true, >=2) = "tcte"
6673     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, *, *) = IllegalStateException
6674     * </pre>
6675     *
6676     * @param text
6677     *            text to search and replace in, no-op if null
6678     * @param searchList
6679     *            the Strings to search for, no-op if null
6680     * @param replacementList
6681     *            the Strings to replace them with, no-op if null
6682     * @param repeat if true, then replace repeatedly
6683     *       until there are no more possible replacements or timeToLive < 0
6684     * @param timeToLive
6685     *            if less than 0 then there is a circular reference and endless
6686     *            loop
6687     * @return the text with any replacements processed, {@code null} if
6688     *         null String input
6689     * @throws IllegalStateException
6690     *             if the search is repeating and there is an endless loop due
6691     *             to outputs of one being inputs to another
6692     * @throws IllegalArgumentException
6693     *             if the lengths of the arrays are not the same (null is ok,
6694     *             and/or size 0)
6695     * @since 2.4
6696     */
6697    private static String replaceEach(
6698            final String text, final String[] searchList, final String[] replacementList, final boolean repeat, final int timeToLive) {
6699
6700        // mchyzer Performance note: This creates very few new objects (one major goal)
6701        // let me know if there are performance requests, we can create a harness to measure
6702
6703        // if recursing, this shouldn't be less than 0
6704        if (timeToLive < 0) {
6705            final Set<String> searchSet = new HashSet<>(Arrays.asList(searchList));
6706            final Set<String> replacementSet = new HashSet<>(Arrays.asList(replacementList));
6707            searchSet.retainAll(replacementSet);
6708            if (!searchSet.isEmpty()) {
6709                throw new IllegalStateException("Aborting to protect against StackOverflowError - " +
6710                        "output of one loop is the input of another");
6711            }
6712        }
6713
6714        if (isEmpty(text) || ArrayUtils.isEmpty(searchList) || ArrayUtils.isEmpty(replacementList) || (ArrayUtils.isNotEmpty(searchList) && timeToLive == -1)) {
6715            return text;
6716        }
6717
6718        final int searchLength = searchList.length;
6719        final int replacementLength = replacementList.length;
6720
6721        // make sure lengths are ok, these need to be equal
6722        if (searchLength != replacementLength) {
6723            throw new IllegalArgumentException("Search and Replace array lengths don't match: "
6724                + searchLength
6725                + " vs "
6726                + replacementLength);
6727        }
6728
6729        // keep track of which still have matches
6730        final boolean[] noMoreMatchesForReplIndex = new boolean[searchLength];
6731
6732        // index on index that the match was found
6733        int textIndex = -1;
6734        int replaceIndex = -1;
6735        int tempIndex = -1;
6736
6737        // index of replace array that will replace the search string found
6738        // NOTE: logic duplicated below START
6739        for (int i = 0; i < searchLength; i++) {
6740            if (noMoreMatchesForReplIndex[i] || isEmpty(searchList[i]) || replacementList[i] == null) {
6741                continue;
6742            }
6743            tempIndex = text.indexOf(searchList[i]);
6744
6745            // see if we need to keep searching for this
6746            if (tempIndex == -1) {
6747                noMoreMatchesForReplIndex[i] = true;
6748            } else if (textIndex == -1 || tempIndex < textIndex) {
6749                textIndex = tempIndex;
6750                replaceIndex = i;
6751            }
6752        }
6753        // NOTE: logic mostly below END
6754
6755        // no search strings found, we are done
6756        if (textIndex == -1) {
6757            return text;
6758        }
6759
6760        int start = 0;
6761
6762        // get a good guess on the size of the result buffer so it doesn't have to double if it goes over a bit
6763        int increase = 0;
6764
6765        // count the replacement text elements that are larger than their corresponding text being replaced
6766        for (int i = 0; i < searchList.length; i++) {
6767            if (searchList[i] == null || replacementList[i] == null) {
6768                continue;
6769            }
6770            final int greater = replacementList[i].length() - searchList[i].length();
6771            if (greater > 0) {
6772                increase += 3 * greater; // assume 3 matches
6773            }
6774        }
6775        // have upper-bound at 20% increase, then let Java take over
6776        increase = Math.min(increase, text.length() / 5);
6777
6778        final StringBuilder buf = new StringBuilder(text.length() + increase);
6779
6780        while (textIndex != -1) {
6781
6782            for (int i = start; i < textIndex; i++) {
6783                buf.append(text.charAt(i));
6784            }
6785            buf.append(replacementList[replaceIndex]);
6786
6787            start = textIndex + searchList[replaceIndex].length();
6788
6789            textIndex = -1;
6790            replaceIndex = -1;
6791            // find the next earliest match
6792            // NOTE: logic mostly duplicated above START
6793            for (int i = 0; i < searchLength; i++) {
6794                if (noMoreMatchesForReplIndex[i] || searchList[i] == null ||
6795                        searchList[i].isEmpty() || replacementList[i] == null) {
6796                    continue;
6797                }
6798                tempIndex = text.indexOf(searchList[i], start);
6799
6800                // see if we need to keep searching for this
6801                if (tempIndex == -1) {
6802                    noMoreMatchesForReplIndex[i] = true;
6803                } else if (textIndex == -1 || tempIndex < textIndex) {
6804                    textIndex = tempIndex;
6805                    replaceIndex = i;
6806                }
6807            }
6808            // NOTE: logic duplicated above END
6809
6810        }
6811        final int textLength = text.length();
6812        for (int i = start; i < textLength; i++) {
6813            buf.append(text.charAt(i));
6814        }
6815        final String result = buf.toString();
6816        if (!repeat) {
6817            return result;
6818        }
6819
6820        return replaceEach(result, searchList, replacementList, repeat, timeToLive - 1);
6821    }
6822
6823    /**
6824     * <p>
6825     * Replaces all occurrences of Strings within another String.
6826     * </p>
6827     *
6828     * <p>
6829     * A {@code null} reference passed to this method is a no-op, or if
6830     * any "search string" or "string to replace" is null, that replace will be
6831     * ignored.
6832     * </p>
6833     *
6834     * <pre>
6835     *  StringUtils.replaceEachRepeatedly(null, *, *) = null
6836     *  StringUtils.replaceEachRepeatedly("", *, *) = ""
6837     *  StringUtils.replaceEachRepeatedly("aba", null, null) = "aba"
6838     *  StringUtils.replaceEachRepeatedly("aba", new String[0], null) = "aba"
6839     *  StringUtils.replaceEachRepeatedly("aba", null, new String[0]) = "aba"
6840     *  StringUtils.replaceEachRepeatedly("aba", new String[]{"a"}, null) = "aba"
6841     *  StringUtils.replaceEachRepeatedly("aba", new String[]{"a"}, new String[]{""}) = "b"
6842     *  StringUtils.replaceEachRepeatedly("aba", new String[]{null}, new String[]{"a"}) = "aba"
6843     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}) = "wcte"
6844     *  (example of how it repeats)
6845     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}) = "tcte"
6846     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}) = IllegalStateException
6847     * </pre>
6848     *
6849     * @param text
6850     *            text to search and replace in, no-op if null
6851     * @param searchList
6852     *            the Strings to search for, no-op if null
6853     * @param replacementList
6854     *            the Strings to replace them with, no-op if null
6855     * @return the text with any replacements processed, {@code null} if
6856     *         null String input
6857     * @throws IllegalStateException
6858     *             if the search is repeating and there is an endless loop due
6859     *             to outputs of one being inputs to another
6860     * @throws IllegalArgumentException
6861     *             if the lengths of the arrays are not the same (null is ok,
6862     *             and/or size 0)
6863     * @since 2.4
6864     */
6865    public static String replaceEachRepeatedly(final String text, final String[] searchList, final String[] replacementList) {
6866        // timeToLive should be 0 if not used or nothing to replace, else it's
6867        // the length of the replace array
6868        final int timeToLive = searchList == null ? 0 : searchList.length;
6869        return replaceEach(text, searchList, replacementList, true, timeToLive);
6870    }
6871
6872    /**
6873     * <p>Replaces the first substring of the text string that matches the given regular expression
6874     * with the given replacement.</p>
6875     *
6876     * This method is a {@code null} safe equivalent to:
6877     * <ul>
6878     *  <li>{@code text.replaceFirst(regex, replacement)}</li>
6879     *  <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(replacement)}</li>
6880     * </ul>
6881     *
6882     * <p>A {@code null} reference passed to this method is a no-op.</p>
6883     *
6884     * <p>The {@link Pattern#DOTALL} option is NOT automatically added.
6885     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
6886     * DOTALL is also known as single-line mode in Perl.</p>
6887     *
6888     * <pre>
6889     * StringUtils.replaceFirst(null, *, *)       = null
6890     * StringUtils.replaceFirst("any", (String) null, *)   = "any"
6891     * StringUtils.replaceFirst("any", *, null)   = "any"
6892     * StringUtils.replaceFirst("", "", "zzz")    = "zzz"
6893     * StringUtils.replaceFirst("", ".*", "zzz")  = "zzz"
6894     * StringUtils.replaceFirst("", ".+", "zzz")  = ""
6895     * StringUtils.replaceFirst("abc", "", "ZZ")  = "ZZabc"
6896     * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z")      = "z\n&lt;__&gt;"
6897     * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", "(?s)&lt;.*&gt;", "z")  = "z"
6898     * StringUtils.replaceFirst("ABCabc123", "[a-z]", "_")          = "ABC_bc123"
6899     * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "_")  = "ABC_123abc"
6900     * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "")   = "ABC123abc"
6901     * StringUtils.replaceFirst("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum  dolor   sit"
6902     * </pre>
6903     *
6904     * @param text  text to search and replace in, may be null
6905     * @param regex  the regular expression to which this string is to be matched
6906     * @param replacement  the string to be substituted for the first match
6907     * @return  the text with the first replacement processed,
6908     *              {@code null} if null String input
6909     *
6910     * @throws  java.util.regex.PatternSyntaxException
6911     *              if the regular expression's syntax is invalid
6912     *
6913     * @see String#replaceFirst(String, String)
6914     * @see java.util.regex.Pattern
6915     * @see java.util.regex.Pattern#DOTALL
6916     * @since 3.5
6917     *
6918     * @deprecated Moved to RegExUtils.
6919     */
6920    @Deprecated
6921    public static String replaceFirst(final String text, final String regex, final String replacement) {
6922        return RegExUtils.replaceFirst(text, regex, replacement);
6923    }
6924
6925    /**
6926    * <p>Case insensitively replaces all occurrences of a String within another String.</p>
6927    *
6928    * <p>A {@code null} reference passed to this method is a no-op.</p>
6929    *
6930    * <pre>
6931    * StringUtils.replaceIgnoreCase(null, *, *)        = null
6932    * StringUtils.replaceIgnoreCase("", *, *)          = ""
6933    * StringUtils.replaceIgnoreCase("any", null, *)    = "any"
6934    * StringUtils.replaceIgnoreCase("any", *, null)    = "any"
6935    * StringUtils.replaceIgnoreCase("any", "", *)      = "any"
6936    * StringUtils.replaceIgnoreCase("aba", "a", null)  = "aba"
6937    * StringUtils.replaceIgnoreCase("abA", "A", "")    = "b"
6938    * StringUtils.replaceIgnoreCase("aba", "A", "z")   = "zbz"
6939    * </pre>
6940    *
6941    * @see #replaceIgnoreCase(String text, String searchString, String replacement, int max)
6942    * @param text  text to search and replace in, may be null
6943    * @param searchString  the String to search for (case insensitive), may be null
6944    * @param replacement  the String to replace it with, may be null
6945    * @return the text with any replacements processed,
6946    *  {@code null} if null String input
6947    * @since 3.5
6948    */
6949   public static String replaceIgnoreCase(final String text, final String searchString, final String replacement) {
6950       return replaceIgnoreCase(text, searchString, replacement, -1);
6951   }
6952
6953    /**
6954     * <p>Case insensitively replaces a String with another String inside a larger String,
6955     * for the first {@code max} values of the search String.</p>
6956     *
6957     * <p>A {@code null} reference passed to this method is a no-op.</p>
6958     *
6959     * <pre>
6960     * StringUtils.replaceIgnoreCase(null, *, *, *)         = null
6961     * StringUtils.replaceIgnoreCase("", *, *, *)           = ""
6962     * StringUtils.replaceIgnoreCase("any", null, *, *)     = "any"
6963     * StringUtils.replaceIgnoreCase("any", *, null, *)     = "any"
6964     * StringUtils.replaceIgnoreCase("any", "", *, *)       = "any"
6965     * StringUtils.replaceIgnoreCase("any", *, *, 0)        = "any"
6966     * StringUtils.replaceIgnoreCase("abaa", "a", null, -1) = "abaa"
6967     * StringUtils.replaceIgnoreCase("abaa", "a", "", -1)   = "b"
6968     * StringUtils.replaceIgnoreCase("abaa", "a", "z", 0)   = "abaa"
6969     * StringUtils.replaceIgnoreCase("abaa", "A", "z", 1)   = "zbaa"
6970     * StringUtils.replaceIgnoreCase("abAa", "a", "z", 2)   = "zbza"
6971     * StringUtils.replaceIgnoreCase("abAa", "a", "z", -1)  = "zbzz"
6972     * </pre>
6973     *
6974     * @param text  text to search and replace in, may be null
6975     * @param searchString  the String to search for (case insensitive), may be null
6976     * @param replacement  the String to replace it with, may be null
6977     * @param max  maximum number of values to replace, or {@code -1} if no maximum
6978     * @return the text with any replacements processed,
6979     *  {@code null} if null String input
6980     * @since 3.5
6981     */
6982    public static String replaceIgnoreCase(final String text, final String searchString, final String replacement, final int max) {
6983        return replace(text, searchString, replacement, max, true);
6984    }
6985
6986    /**
6987     * <p>Replaces a String with another String inside a larger String, once.</p>
6988     *
6989     * <p>A {@code null} reference passed to this method is a no-op.</p>
6990     *
6991     * <pre>
6992     * StringUtils.replaceOnce(null, *, *)        = null
6993     * StringUtils.replaceOnce("", *, *)          = ""
6994     * StringUtils.replaceOnce("any", null, *)    = "any"
6995     * StringUtils.replaceOnce("any", *, null)    = "any"
6996     * StringUtils.replaceOnce("any", "", *)      = "any"
6997     * StringUtils.replaceOnce("aba", "a", null)  = "aba"
6998     * StringUtils.replaceOnce("aba", "a", "")    = "ba"
6999     * StringUtils.replaceOnce("aba", "a", "z")   = "zba"
7000     * </pre>
7001     *
7002     * @see #replace(String text, String searchString, String replacement, int max)
7003     * @param text  text to search and replace in, may be null
7004     * @param searchString  the String to search for, may be null
7005     * @param replacement  the String to replace with, may be null
7006     * @return the text with any replacements processed,
7007     *  {@code null} if null String input
7008     */
7009    public static String replaceOnce(final String text, final String searchString, final String replacement) {
7010        return replace(text, searchString, replacement, 1);
7011    }
7012
7013    /**
7014     * <p>Case insensitively replaces a String with another String inside a larger String, once.</p>
7015     *
7016     * <p>A {@code null} reference passed to this method is a no-op.</p>
7017     *
7018     * <pre>
7019     * StringUtils.replaceOnceIgnoreCase(null, *, *)        = null
7020     * StringUtils.replaceOnceIgnoreCase("", *, *)          = ""
7021     * StringUtils.replaceOnceIgnoreCase("any", null, *)    = "any"
7022     * StringUtils.replaceOnceIgnoreCase("any", *, null)    = "any"
7023     * StringUtils.replaceOnceIgnoreCase("any", "", *)      = "any"
7024     * StringUtils.replaceOnceIgnoreCase("aba", "a", null)  = "aba"
7025     * StringUtils.replaceOnceIgnoreCase("aba", "a", "")    = "ba"
7026     * StringUtils.replaceOnceIgnoreCase("aba", "a", "z")   = "zba"
7027     * StringUtils.replaceOnceIgnoreCase("FoOFoofoo", "foo", "") = "Foofoo"
7028     * </pre>
7029     *
7030     * @see #replaceIgnoreCase(String text, String searchString, String replacement, int max)
7031     * @param text  text to search and replace in, may be null
7032     * @param searchString  the String to search for (case insensitive), may be null
7033     * @param replacement  the String to replace with, may be null
7034     * @return the text with any replacements processed,
7035     *  {@code null} if null String input
7036     * @since 3.5
7037     */
7038    public static String replaceOnceIgnoreCase(final String text, final String searchString, final String replacement) {
7039        return replaceIgnoreCase(text, searchString, replacement, 1);
7040    }
7041
7042    /**
7043     * <p>Replaces each substring of the source String that matches the given regular expression with the given
7044     * replacement using the {@link Pattern#DOTALL} option. DOTALL is also known as single-line mode in Perl.</p>
7045     *
7046     * This call is a {@code null} safe equivalent to:
7047     * <ul>
7048     * <li>{@code source.replaceAll(&quot;(?s)&quot; + regex, replacement)}</li>
7049     * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(source).replaceAll(replacement)}</li>
7050     * </ul>
7051     *
7052     * <p>A {@code null} reference passed to this method is a no-op.</p>
7053     *
7054     * <pre>
7055     * StringUtils.replacePattern(null, *, *)       = null
7056     * StringUtils.replacePattern("any", (String) null, *)   = "any"
7057     * StringUtils.replacePattern("any", *, null)   = "any"
7058     * StringUtils.replacePattern("", "", "zzz")    = "zzz"
7059     * StringUtils.replacePattern("", ".*", "zzz")  = "zzz"
7060     * StringUtils.replacePattern("", ".+", "zzz")  = ""
7061     * StringUtils.replacePattern("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z")       = "z"
7062     * StringUtils.replacePattern("ABCabc123", "[a-z]", "_")       = "ABC___123"
7063     * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
7064     * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
7065     * StringUtils.replacePattern("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
7066     * </pre>
7067     *
7068     * @param source
7069     *            the source string
7070     * @param regex
7071     *            the regular expression to which this string is to be matched
7072     * @param replacement
7073     *            the string to be substituted for each match
7074     * @return The resulting {@code String}
7075     * @see #replaceAll(String, String, String)
7076     * @see String#replaceAll(String, String)
7077     * @see Pattern#DOTALL
7078     * @since 3.2
7079     * @since 3.5 Changed {@code null} reference passed to this method is a no-op.
7080     *
7081     * @deprecated Moved to RegExUtils.
7082     */
7083    @Deprecated
7084    public static String replacePattern(final String source, final String regex, final String replacement) {
7085        return RegExUtils.replacePattern(source, regex, replacement);
7086    }
7087
7088    /**
7089     * <p>Reverses a String as per {@link StringBuilder#reverse()}.</p>
7090     *
7091     * <p>A {@code null} String returns {@code null}.</p>
7092     *
7093     * <pre>
7094     * StringUtils.reverse(null)  = null
7095     * StringUtils.reverse("")    = ""
7096     * StringUtils.reverse("bat") = "tab"
7097     * </pre>
7098     *
7099     * @param str  the String to reverse, may be null
7100     * @return the reversed String, {@code null} if null String input
7101     */
7102    public static String reverse(final String str) {
7103        if (str == null) {
7104            return null;
7105        }
7106        return new StringBuilder(str).reverse().toString();
7107    }
7108
7109    /**
7110     * <p>Reverses a String that is delimited by a specific character.</p>
7111     *
7112     * <p>The Strings between the delimiters are not reversed.
7113     * Thus java.lang.String becomes String.lang.java (if the delimiter
7114     * is {@code '.'}).</p>
7115     *
7116     * <pre>
7117     * StringUtils.reverseDelimited(null, *)      = null
7118     * StringUtils.reverseDelimited("", *)        = ""
7119     * StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
7120     * StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"
7121     * </pre>
7122     *
7123     * @param str  the String to reverse, may be null
7124     * @param separatorChar  the separator character to use
7125     * @return the reversed String, {@code null} if null String input
7126     * @since 2.0
7127     */
7128    public static String reverseDelimited(final String str, final char separatorChar) {
7129        if (str == null) {
7130            return null;
7131        }
7132        // could implement manually, but simple way is to reuse other,
7133        // probably slower, methods.
7134        final String[] strs = split(str, separatorChar);
7135        ArrayUtils.reverse(strs);
7136        return join(strs, separatorChar);
7137    }
7138
7139    /**
7140     * <p>Gets the rightmost {@code len} characters of a String.</p>
7141     *
7142     * <p>If {@code len} characters are not available, or the String
7143     * is {@code null}, the String will be returned without an
7144     * an exception. An empty String is returned if len is negative.</p>
7145     *
7146     * <pre>
7147     * StringUtils.right(null, *)    = null
7148     * StringUtils.right(*, -ve)     = ""
7149     * StringUtils.right("", *)      = ""
7150     * StringUtils.right("abc", 0)   = ""
7151     * StringUtils.right("abc", 2)   = "bc"
7152     * StringUtils.right("abc", 4)   = "abc"
7153     * </pre>
7154     *
7155     * @param str  the String to get the rightmost characters from, may be null
7156     * @param len  the length of the required String
7157     * @return the rightmost characters, {@code null} if null String input
7158     */
7159    public static String right(final String str, final int len) {
7160        if (str == null) {
7161            return null;
7162        }
7163        if (len < 0) {
7164            return EMPTY;
7165        }
7166        if (str.length() <= len) {
7167            return str;
7168        }
7169        return str.substring(str.length() - len);
7170    }
7171
7172    /**
7173     * <p>Right pad a String with spaces (' ').</p>
7174     *
7175     * <p>The String is padded to the size of {@code size}.</p>
7176     *
7177     * <pre>
7178     * StringUtils.rightPad(null, *)   = null
7179     * StringUtils.rightPad("", 3)     = "   "
7180     * StringUtils.rightPad("bat", 3)  = "bat"
7181     * StringUtils.rightPad("bat", 5)  = "bat  "
7182     * StringUtils.rightPad("bat", 1)  = "bat"
7183     * StringUtils.rightPad("bat", -1) = "bat"
7184     * </pre>
7185     *
7186     * @param str  the String to pad out, may be null
7187     * @param size  the size to pad to
7188     * @return right padded String or original String if no padding is necessary,
7189     *  {@code null} if null String input
7190     */
7191    public static String rightPad(final String str, final int size) {
7192        return rightPad(str, size, ' ');
7193    }
7194
7195    /**
7196     * <p>Right pad a String with a specified character.</p>
7197     *
7198     * <p>The String is padded to the size of {@code size}.</p>
7199     *
7200     * <pre>
7201     * StringUtils.rightPad(null, *, *)     = null
7202     * StringUtils.rightPad("", 3, 'z')     = "zzz"
7203     * StringUtils.rightPad("bat", 3, 'z')  = "bat"
7204     * StringUtils.rightPad("bat", 5, 'z')  = "batzz"
7205     * StringUtils.rightPad("bat", 1, 'z')  = "bat"
7206     * StringUtils.rightPad("bat", -1, 'z') = "bat"
7207     * </pre>
7208     *
7209     * @param str  the String to pad out, may be null
7210     * @param size  the size to pad to
7211     * @param padChar  the character to pad with
7212     * @return right padded String or original String if no padding is necessary,
7213     *  {@code null} if null String input
7214     * @since 2.0
7215     */
7216    public static String rightPad(final String str, final int size, final char padChar) {
7217        if (str == null) {
7218            return null;
7219        }
7220        final int pads = size - str.length();
7221        if (pads <= 0) {
7222            return str; // returns original String when possible
7223        }
7224        if (pads > PAD_LIMIT) {
7225            return rightPad(str, size, String.valueOf(padChar));
7226        }
7227        return str.concat(repeat(padChar, pads));
7228    }
7229
7230    /**
7231     * <p>Right pad a String with a specified String.</p>
7232     *
7233     * <p>The String is padded to the size of {@code size}.</p>
7234     *
7235     * <pre>
7236     * StringUtils.rightPad(null, *, *)      = null
7237     * StringUtils.rightPad("", 3, "z")      = "zzz"
7238     * StringUtils.rightPad("bat", 3, "yz")  = "bat"
7239     * StringUtils.rightPad("bat", 5, "yz")  = "batyz"
7240     * StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
7241     * StringUtils.rightPad("bat", 1, "yz")  = "bat"
7242     * StringUtils.rightPad("bat", -1, "yz") = "bat"
7243     * StringUtils.rightPad("bat", 5, null)  = "bat  "
7244     * StringUtils.rightPad("bat", 5, "")    = "bat  "
7245     * </pre>
7246     *
7247     * @param str  the String to pad out, may be null
7248     * @param size  the size to pad to
7249     * @param padStr  the String to pad with, null or empty treated as single space
7250     * @return right padded String or original String if no padding is necessary,
7251     *  {@code null} if null String input
7252     */
7253    public static String rightPad(final String str, final int size, String padStr) {
7254        if (str == null) {
7255            return null;
7256        }
7257        if (isEmpty(padStr)) {
7258            padStr = SPACE;
7259        }
7260        final int padLen = padStr.length();
7261        final int strLen = str.length();
7262        final int pads = size - strLen;
7263        if (pads <= 0) {
7264            return str; // returns original String when possible
7265        }
7266        if (padLen == 1 && pads <= PAD_LIMIT) {
7267            return rightPad(str, size, padStr.charAt(0));
7268        }
7269
7270        if (pads == padLen) {
7271            return str.concat(padStr);
7272        } else if (pads < padLen) {
7273            return str.concat(padStr.substring(0, pads));
7274        } else {
7275            final char[] padding = new char[pads];
7276            final char[] padChars = padStr.toCharArray();
7277            for (int i = 0; i < pads; i++) {
7278                padding[i] = padChars[i % padLen];
7279            }
7280            return str.concat(new String(padding));
7281        }
7282    }
7283
7284    /**
7285     * <p>Rotate (circular shift) a String of {@code shift} characters.</p>
7286     * <ul>
7287     *  <li>If {@code shift > 0}, right circular shift (ex : ABCDEF =&gt; FABCDE)</li>
7288     *  <li>If {@code shift < 0}, left circular shift (ex : ABCDEF =&gt; BCDEFA)</li>
7289     * </ul>
7290     *
7291     * <pre>
7292     * StringUtils.rotate(null, *)        = null
7293     * StringUtils.rotate("", *)          = ""
7294     * StringUtils.rotate("abcdefg", 0)   = "abcdefg"
7295     * StringUtils.rotate("abcdefg", 2)   = "fgabcde"
7296     * StringUtils.rotate("abcdefg", -2)  = "cdefgab"
7297     * StringUtils.rotate("abcdefg", 7)   = "abcdefg"
7298     * StringUtils.rotate("abcdefg", -7)  = "abcdefg"
7299     * StringUtils.rotate("abcdefg", 9)   = "fgabcde"
7300     * StringUtils.rotate("abcdefg", -9)  = "cdefgab"
7301     * </pre>
7302     *
7303     * @param str  the String to rotate, may be null
7304     * @param shift  number of time to shift (positive : right shift, negative : left shift)
7305     * @return the rotated String,
7306     *          or the original String if {@code shift == 0},
7307     *          or {@code null} if null String input
7308     * @since 3.5
7309     */
7310    public static String rotate(final String str, final int shift) {
7311        if (str == null) {
7312            return null;
7313        }
7314
7315        final int strLen = str.length();
7316        if (shift == 0 || strLen == 0 || shift % strLen == 0) {
7317            return str;
7318        }
7319
7320        final StringBuilder builder = new StringBuilder(strLen);
7321        final int offset = - (shift % strLen);
7322        builder.append(substring(str, offset));
7323        builder.append(substring(str, 0, offset));
7324        return builder.toString();
7325    }
7326
7327    /**
7328     * <p>Splits the provided text into an array, using whitespace as the
7329     * separator.
7330     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
7331     *
7332     * <p>The separator is not included in the returned String array.
7333     * Adjacent separators are treated as one separator.
7334     * For more control over the split use the StrTokenizer class.</p>
7335     *
7336     * <p>A {@code null} input String returns {@code null}.</p>
7337     *
7338     * <pre>
7339     * StringUtils.split(null)       = null
7340     * StringUtils.split("")         = []
7341     * StringUtils.split("abc def")  = ["abc", "def"]
7342     * StringUtils.split("abc  def") = ["abc", "def"]
7343     * StringUtils.split(" abc ")    = ["abc"]
7344     * </pre>
7345     *
7346     * @param str  the String to parse, may be null
7347     * @return an array of parsed Strings, {@code null} if null String input
7348     */
7349    public static String[] split(final String str) {
7350        return split(str, null, -1);
7351    }
7352
7353    /**
7354     * <p>Splits the provided text into an array, separator specified.
7355     * This is an alternative to using StringTokenizer.</p>
7356     *
7357     * <p>The separator is not included in the returned String array.
7358     * Adjacent separators are treated as one separator.
7359     * For more control over the split use the StrTokenizer class.</p>
7360     *
7361     * <p>A {@code null} input String returns {@code null}.</p>
7362     *
7363     * <pre>
7364     * StringUtils.split(null, *)         = null
7365     * StringUtils.split("", *)           = []
7366     * StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
7367     * StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
7368     * StringUtils.split("a:b:c", '.')    = ["a:b:c"]
7369     * StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
7370     * </pre>
7371     *
7372     * @param str  the String to parse, may be null
7373     * @param separatorChar  the character used as the delimiter
7374     * @return an array of parsed Strings, {@code null} if null String input
7375     * @since 2.0
7376     */
7377    public static String[] split(final String str, final char separatorChar) {
7378        return splitWorker(str, separatorChar, false);
7379    }
7380
7381    /**
7382     * <p>Splits the provided text into an array, separators specified.
7383     * This is an alternative to using StringTokenizer.</p>
7384     *
7385     * <p>The separator is not included in the returned String array.
7386     * Adjacent separators are treated as one separator.
7387     * For more control over the split use the StrTokenizer class.</p>
7388     *
7389     * <p>A {@code null} input String returns {@code null}.
7390     * A {@code null} separatorChars splits on whitespace.</p>
7391     *
7392     * <pre>
7393     * StringUtils.split(null, *)         = null
7394     * StringUtils.split("", *)           = []
7395     * StringUtils.split("abc def", null) = ["abc", "def"]
7396     * StringUtils.split("abc def", " ")  = ["abc", "def"]
7397     * StringUtils.split("abc  def", " ") = ["abc", "def"]
7398     * StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
7399     * </pre>
7400     *
7401     * @param str  the String to parse, may be null
7402     * @param separatorChars  the characters used as the delimiters,
7403     *  {@code null} splits on whitespace
7404     * @return an array of parsed Strings, {@code null} if null String input
7405     */
7406    public static String[] split(final String str, final String separatorChars) {
7407        return splitWorker(str, separatorChars, -1, false);
7408    }
7409
7410    /**
7411     * <p>Splits the provided text into an array with a maximum length,
7412     * separators specified.</p>
7413     *
7414     * <p>The separator is not included in the returned String array.
7415     * Adjacent separators are treated as one separator.</p>
7416     *
7417     * <p>A {@code null} input String returns {@code null}.
7418     * A {@code null} separatorChars splits on whitespace.</p>
7419     *
7420     * <p>If more than {@code max} delimited substrings are found, the last
7421     * returned string includes all characters after the first {@code max - 1}
7422     * returned strings (including separator characters).</p>
7423     *
7424     * <pre>
7425     * StringUtils.split(null, *, *)            = null
7426     * StringUtils.split("", *, *)              = []
7427     * StringUtils.split("ab cd ef", null, 0)   = ["ab", "cd", "ef"]
7428     * StringUtils.split("ab   cd ef", null, 0) = ["ab", "cd", "ef"]
7429     * StringUtils.split("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
7430     * StringUtils.split("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
7431     * </pre>
7432     *
7433     * @param str  the String to parse, may be null
7434     * @param separatorChars  the characters used as the delimiters,
7435     *  {@code null} splits on whitespace
7436     * @param max  the maximum number of elements to include in the
7437     *  array. A zero or negative value implies no limit
7438     * @return an array of parsed Strings, {@code null} if null String input
7439     */
7440    public static String[] split(final String str, final String separatorChars, final int max) {
7441        return splitWorker(str, separatorChars, max, false);
7442    }
7443
7444    /**
7445     * <p>Splits a String by Character type as returned by
7446     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7447     * characters of the same type are returned as complete tokens.
7448     * <pre>
7449     * StringUtils.splitByCharacterType(null)         = null
7450     * StringUtils.splitByCharacterType("")           = []
7451     * StringUtils.splitByCharacterType("ab de fg")   = ["ab", " ", "de", " ", "fg"]
7452     * StringUtils.splitByCharacterType("ab   de fg") = ["ab", "   ", "de", " ", "fg"]
7453     * StringUtils.splitByCharacterType("ab:cd:ef")   = ["ab", ":", "cd", ":", "ef"]
7454     * StringUtils.splitByCharacterType("number5")    = ["number", "5"]
7455     * StringUtils.splitByCharacterType("fooBar")     = ["foo", "B", "ar"]
7456     * StringUtils.splitByCharacterType("foo200Bar")  = ["foo", "200", "B", "ar"]
7457     * StringUtils.splitByCharacterType("ASFRules")   = ["ASFR", "ules"]
7458     * </pre>
7459     * @param str the String to split, may be {@code null}
7460     * @return an array of parsed Strings, {@code null} if null String input
7461     * @since 2.4
7462     */
7463    public static String[] splitByCharacterType(final String str) {
7464        return splitByCharacterType(str, false);
7465    }
7466
7467    /**
7468     * <p>Splits a String by Character type as returned by
7469     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7470     * characters of the same type are returned as complete tokens, with the
7471     * following exception: if {@code camelCase} is {@code true},
7472     * the character of type {@code Character.UPPERCASE_LETTER}, if any,
7473     * immediately preceding a token of type {@code Character.LOWERCASE_LETTER}
7474     * will belong to the following token rather than to the preceding, if any,
7475     * {@code Character.UPPERCASE_LETTER} token.
7476     * @param str the String to split, may be {@code null}
7477     * @param camelCase whether to use so-called "camel-case" for letter types
7478     * @return an array of parsed Strings, {@code null} if null String input
7479     * @since 2.4
7480     */
7481    private static String[] splitByCharacterType(final String str, final boolean camelCase) {
7482        if (str == null) {
7483            return null;
7484        }
7485        if (str.isEmpty()) {
7486            return ArrayUtils.EMPTY_STRING_ARRAY;
7487        }
7488        final char[] c = str.toCharArray();
7489        final List<String> list = new ArrayList<>();
7490        int tokenStart = 0;
7491        int currentType = Character.getType(c[tokenStart]);
7492        for (int pos = tokenStart + 1; pos < c.length; pos++) {
7493            final int type = Character.getType(c[pos]);
7494            if (type == currentType) {
7495                continue;
7496            }
7497            if (camelCase && type == Character.LOWERCASE_LETTER && currentType == Character.UPPERCASE_LETTER) {
7498                final int newTokenStart = pos - 1;
7499                if (newTokenStart != tokenStart) {
7500                    list.add(new String(c, tokenStart, newTokenStart - tokenStart));
7501                    tokenStart = newTokenStart;
7502                }
7503            } else {
7504                list.add(new String(c, tokenStart, pos - tokenStart));
7505                tokenStart = pos;
7506            }
7507            currentType = type;
7508        }
7509        list.add(new String(c, tokenStart, c.length - tokenStart));
7510        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7511    }
7512
7513    /**
7514     * <p>Splits a String by Character type as returned by
7515     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7516     * characters of the same type are returned as complete tokens, with the
7517     * following exception: the character of type
7518     * {@code Character.UPPERCASE_LETTER}, if any, immediately
7519     * preceding a token of type {@code Character.LOWERCASE_LETTER}
7520     * will belong to the following token rather than to the preceding, if any,
7521     * {@code Character.UPPERCASE_LETTER} token.
7522     * <pre>
7523     * StringUtils.splitByCharacterTypeCamelCase(null)         = null
7524     * StringUtils.splitByCharacterTypeCamelCase("")           = []
7525     * StringUtils.splitByCharacterTypeCamelCase("ab de fg")   = ["ab", " ", "de", " ", "fg"]
7526     * StringUtils.splitByCharacterTypeCamelCase("ab   de fg") = ["ab", "   ", "de", " ", "fg"]
7527     * StringUtils.splitByCharacterTypeCamelCase("ab:cd:ef")   = ["ab", ":", "cd", ":", "ef"]
7528     * StringUtils.splitByCharacterTypeCamelCase("number5")    = ["number", "5"]
7529     * StringUtils.splitByCharacterTypeCamelCase("fooBar")     = ["foo", "Bar"]
7530     * StringUtils.splitByCharacterTypeCamelCase("foo200Bar")  = ["foo", "200", "Bar"]
7531     * StringUtils.splitByCharacterTypeCamelCase("ASFRules")   = ["ASF", "Rules"]
7532     * </pre>
7533     * @param str the String to split, may be {@code null}
7534     * @return an array of parsed Strings, {@code null} if null String input
7535     * @since 2.4
7536     */
7537    public static String[] splitByCharacterTypeCamelCase(final String str) {
7538        return splitByCharacterType(str, true);
7539    }
7540
7541    /**
7542     * <p>Splits the provided text into an array, separator string specified.</p>
7543     *
7544     * <p>The separator(s) will not be included in the returned String array.
7545     * Adjacent separators are treated as one separator.</p>
7546     *
7547     * <p>A {@code null} input String returns {@code null}.
7548     * A {@code null} separator splits on whitespace.</p>
7549     *
7550     * <pre>
7551     * StringUtils.splitByWholeSeparator(null, *)               = null
7552     * StringUtils.splitByWholeSeparator("", *)                 = []
7553     * StringUtils.splitByWholeSeparator("ab de fg", null)      = ["ab", "de", "fg"]
7554     * StringUtils.splitByWholeSeparator("ab   de fg", null)    = ["ab", "de", "fg"]
7555     * StringUtils.splitByWholeSeparator("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
7556     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
7557     * </pre>
7558     *
7559     * @param str  the String to parse, may be null
7560     * @param separator  String containing the String to be used as a delimiter,
7561     *  {@code null} splits on whitespace
7562     * @return an array of parsed Strings, {@code null} if null String was input
7563     */
7564    public static String[] splitByWholeSeparator(final String str, final String separator) {
7565        return splitByWholeSeparatorWorker(str, separator, -1, false);
7566    }
7567
7568    /**
7569     * <p>Splits the provided text into an array, separator string specified.
7570     * Returns a maximum of {@code max} substrings.</p>
7571     *
7572     * <p>The separator(s) will not be included in the returned String array.
7573     * Adjacent separators are treated as one separator.</p>
7574     *
7575     * <p>A {@code null} input String returns {@code null}.
7576     * A {@code null} separator splits on whitespace.</p>
7577     *
7578     * <pre>
7579     * StringUtils.splitByWholeSeparator(null, *, *)               = null
7580     * StringUtils.splitByWholeSeparator("", *, *)                 = []
7581     * StringUtils.splitByWholeSeparator("ab de fg", null, 0)      = ["ab", "de", "fg"]
7582     * StringUtils.splitByWholeSeparator("ab   de fg", null, 0)    = ["ab", "de", "fg"]
7583     * StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
7584     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
7585     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
7586     * </pre>
7587     *
7588     * @param str  the String to parse, may be null
7589     * @param separator  String containing the String to be used as a delimiter,
7590     *  {@code null} splits on whitespace
7591     * @param max  the maximum number of elements to include in the returned
7592     *  array. A zero or negative value implies no limit.
7593     * @return an array of parsed Strings, {@code null} if null String was input
7594     */
7595    public static String[] splitByWholeSeparator( final String str, final String separator, final int max) {
7596        return splitByWholeSeparatorWorker(str, separator, max, false);
7597    }
7598
7599    /**
7600     * <p>Splits the provided text into an array, separator string specified. </p>
7601     *
7602     * <p>The separator is not included in the returned String array.
7603     * Adjacent separators are treated as separators for empty tokens.
7604     * For more control over the split use the StrTokenizer class.</p>
7605     *
7606     * <p>A {@code null} input String returns {@code null}.
7607     * A {@code null} separator splits on whitespace.</p>
7608     *
7609     * <pre>
7610     * StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *)               = null
7611     * StringUtils.splitByWholeSeparatorPreserveAllTokens("", *)                 = []
7612     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null)      = ["ab", "de", "fg"]
7613     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null)    = ["ab", "", "", "de", "fg"]
7614     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
7615     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
7616     * </pre>
7617     *
7618     * @param str  the String to parse, may be null
7619     * @param separator  String containing the String to be used as a delimiter,
7620     *  {@code null} splits on whitespace
7621     * @return an array of parsed Strings, {@code null} if null String was input
7622     * @since 2.4
7623     */
7624    public static String[] splitByWholeSeparatorPreserveAllTokens(final String str, final String separator) {
7625        return splitByWholeSeparatorWorker(str, separator, -1, true);
7626    }
7627
7628    /**
7629     * <p>Splits the provided text into an array, separator string specified.
7630     * Returns a maximum of {@code max} substrings.</p>
7631     *
7632     * <p>The separator is not included in the returned String array.
7633     * Adjacent separators are treated as separators for empty tokens.
7634     * For more control over the split use the StrTokenizer class.</p>
7635     *
7636     * <p>A {@code null} input String returns {@code null}.
7637     * A {@code null} separator splits on whitespace.</p>
7638     *
7639     * <pre>
7640     * StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *, *)               = null
7641     * StringUtils.splitByWholeSeparatorPreserveAllTokens("", *, *)                 = []
7642     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0)      = ["ab", "de", "fg"]
7643     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null, 0)    = ["ab", "", "", "de", "fg"]
7644     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
7645     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
7646     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
7647     * </pre>
7648     *
7649     * @param str  the String to parse, may be null
7650     * @param separator  String containing the String to be used as a delimiter,
7651     *  {@code null} splits on whitespace
7652     * @param max  the maximum number of elements to include in the returned
7653     *  array. A zero or negative value implies no limit.
7654     * @return an array of parsed Strings, {@code null} if null String was input
7655     * @since 2.4
7656     */
7657    public static String[] splitByWholeSeparatorPreserveAllTokens(final String str, final String separator, final int max) {
7658        return splitByWholeSeparatorWorker(str, separator, max, true);
7659    }
7660
7661    /**
7662     * Performs the logic for the {@code splitByWholeSeparatorPreserveAllTokens} methods.
7663     *
7664     * @param str  the String to parse, may be {@code null}
7665     * @param separator  String containing the String to be used as a delimiter,
7666     *  {@code null} splits on whitespace
7667     * @param max  the maximum number of elements to include in the returned
7668     *  array. A zero or negative value implies no limit.
7669     * @param preserveAllTokens if {@code true}, adjacent separators are
7670     * treated as empty token separators; if {@code false}, adjacent
7671     * separators are treated as one separator.
7672     * @return an array of parsed Strings, {@code null} if null String input
7673     * @since 2.4
7674     */
7675    private static String[] splitByWholeSeparatorWorker(
7676            final String str, final String separator, final int max, final boolean preserveAllTokens) {
7677        if (str == null) {
7678            return null;
7679        }
7680
7681        final int len = str.length();
7682
7683        if (len == 0) {
7684            return ArrayUtils.EMPTY_STRING_ARRAY;
7685        }
7686
7687        if (separator == null || EMPTY.equals(separator)) {
7688            // Split on whitespace.
7689            return splitWorker(str, null, max, preserveAllTokens);
7690        }
7691
7692        final int separatorLength = separator.length();
7693
7694        final ArrayList<String> substrings = new ArrayList<>();
7695        int numberOfSubstrings = 0;
7696        int beg = 0;
7697        int end = 0;
7698        while (end < len) {
7699            end = str.indexOf(separator, beg);
7700
7701            if (end > -1) {
7702                if (end > beg) {
7703                    numberOfSubstrings += 1;
7704
7705                    if (numberOfSubstrings == max) {
7706                        end = len;
7707                        substrings.add(str.substring(beg));
7708                    } else {
7709                        // The following is OK, because String.substring( beg, end ) excludes
7710                        // the character at the position 'end'.
7711                        substrings.add(str.substring(beg, end));
7712
7713                        // Set the starting point for the next search.
7714                        // The following is equivalent to beg = end + (separatorLength - 1) + 1,
7715                        // which is the right calculation:
7716                        beg = end + separatorLength;
7717                    }
7718                } else {
7719                    // We found a consecutive occurrence of the separator, so skip it.
7720                    if (preserveAllTokens) {
7721                        numberOfSubstrings += 1;
7722                        if (numberOfSubstrings == max) {
7723                            end = len;
7724                            substrings.add(str.substring(beg));
7725                        } else {
7726                            substrings.add(EMPTY);
7727                        }
7728                    }
7729                    beg = end + separatorLength;
7730                }
7731            } else {
7732                // String.substring( beg ) goes from 'beg' to the end of the String.
7733                substrings.add(str.substring(beg));
7734                end = len;
7735            }
7736        }
7737
7738        return substrings.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7739    }
7740
7741    /**
7742     * <p>Splits the provided text into an array, using whitespace as the
7743     * separator, preserving all tokens, including empty tokens created by
7744     * adjacent separators. This is an alternative to using StringTokenizer.
7745     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
7746     *
7747     * <p>The separator is not included in the returned String array.
7748     * Adjacent separators are treated as separators for empty tokens.
7749     * For more control over the split use the StrTokenizer class.</p>
7750     *
7751     * <p>A {@code null} input String returns {@code null}.</p>
7752     *
7753     * <pre>
7754     * StringUtils.splitPreserveAllTokens(null)       = null
7755     * StringUtils.splitPreserveAllTokens("")         = []
7756     * StringUtils.splitPreserveAllTokens("abc def")  = ["abc", "def"]
7757     * StringUtils.splitPreserveAllTokens("abc  def") = ["abc", "", "def"]
7758     * StringUtils.splitPreserveAllTokens(" abc ")    = ["", "abc", ""]
7759     * </pre>
7760     *
7761     * @param str  the String to parse, may be {@code null}
7762     * @return an array of parsed Strings, {@code null} if null String input
7763     * @since 2.1
7764     */
7765    public static String[] splitPreserveAllTokens(final String str) {
7766        return splitWorker(str, null, -1, true);
7767    }
7768
7769    /**
7770     * <p>Splits the provided text into an array, separator specified,
7771     * preserving all tokens, including empty tokens created by adjacent
7772     * separators. This is an alternative to using StringTokenizer.</p>
7773     *
7774     * <p>The separator is not included in the returned String array.
7775     * Adjacent separators are treated as separators for empty tokens.
7776     * For more control over the split use the StrTokenizer class.</p>
7777     *
7778     * <p>A {@code null} input String returns {@code null}.</p>
7779     *
7780     * <pre>
7781     * StringUtils.splitPreserveAllTokens(null, *)         = null
7782     * StringUtils.splitPreserveAllTokens("", *)           = []
7783     * StringUtils.splitPreserveAllTokens("a.b.c", '.')    = ["a", "b", "c"]
7784     * StringUtils.splitPreserveAllTokens("a..b.c", '.')   = ["a", "", "b", "c"]
7785     * StringUtils.splitPreserveAllTokens("a:b:c", '.')    = ["a:b:c"]
7786     * StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
7787     * StringUtils.splitPreserveAllTokens("a b c", ' ')    = ["a", "b", "c"]
7788     * StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", ""]
7789     * StringUtils.splitPreserveAllTokens("a b c  ", ' ')   = ["a", "b", "c", "", ""]
7790     * StringUtils.splitPreserveAllTokens(" a b c", ' ')   = ["", a", "b", "c"]
7791     * StringUtils.splitPreserveAllTokens("  a b c", ' ')  = ["", "", a", "b", "c"]
7792     * StringUtils.splitPreserveAllTokens(" a b c ", ' ')  = ["", a", "b", "c", ""]
7793     * </pre>
7794     *
7795     * @param str  the String to parse, may be {@code null}
7796     * @param separatorChar  the character used as the delimiter,
7797     *  {@code null} splits on whitespace
7798     * @return an array of parsed Strings, {@code null} if null String input
7799     * @since 2.1
7800     */
7801    public static String[] splitPreserveAllTokens(final String str, final char separatorChar) {
7802        return splitWorker(str, separatorChar, true);
7803    }
7804
7805    /**
7806     * <p>Splits the provided text into an array, separators specified,
7807     * preserving all tokens, including empty tokens created by adjacent
7808     * separators. This is an alternative to using StringTokenizer.</p>
7809     *
7810     * <p>The separator is not included in the returned String array.
7811     * Adjacent separators are treated as separators for empty tokens.
7812     * For more control over the split use the StrTokenizer class.</p>
7813     *
7814     * <p>A {@code null} input String returns {@code null}.
7815     * A {@code null} separatorChars splits on whitespace.</p>
7816     *
7817     * <pre>
7818     * StringUtils.splitPreserveAllTokens(null, *)           = null
7819     * StringUtils.splitPreserveAllTokens("", *)             = []
7820     * StringUtils.splitPreserveAllTokens("abc def", null)   = ["abc", "def"]
7821     * StringUtils.splitPreserveAllTokens("abc def", " ")    = ["abc", "def"]
7822     * StringUtils.splitPreserveAllTokens("abc  def", " ")   = ["abc", "", def"]
7823     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":")   = ["ab", "cd", "ef"]
7824     * StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":")  = ["ab", "cd", "ef", ""]
7825     * StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
7826     * StringUtils.splitPreserveAllTokens("ab::cd:ef", ":")  = ["ab", "", cd", "ef"]
7827     * StringUtils.splitPreserveAllTokens(":cd:ef", ":")     = ["", cd", "ef"]
7828     * StringUtils.splitPreserveAllTokens("::cd:ef", ":")    = ["", "", cd", "ef"]
7829     * StringUtils.splitPreserveAllTokens(":cd:ef:", ":")    = ["", cd", "ef", ""]
7830     * </pre>
7831     *
7832     * @param str  the String to parse, may be {@code null}
7833     * @param separatorChars  the characters used as the delimiters,
7834     *  {@code null} splits on whitespace
7835     * @return an array of parsed Strings, {@code null} if null String input
7836     * @since 2.1
7837     */
7838    public static String[] splitPreserveAllTokens(final String str, final String separatorChars) {
7839        return splitWorker(str, separatorChars, -1, true);
7840    }
7841
7842    /**
7843     * <p>Splits the provided text into an array with a maximum length,
7844     * separators specified, preserving all tokens, including empty tokens
7845     * created by adjacent separators.</p>
7846     *
7847     * <p>The separator is not included in the returned String array.
7848     * Adjacent separators are treated as separators for empty tokens.
7849     * Adjacent separators are treated as one separator.</p>
7850     *
7851     * <p>A {@code null} input String returns {@code null}.
7852     * A {@code null} separatorChars splits on whitespace.</p>
7853     *
7854     * <p>If more than {@code max} delimited substrings are found, the last
7855     * returned string includes all characters after the first {@code max - 1}
7856     * returned strings (including separator characters).</p>
7857     *
7858     * <pre>
7859     * StringUtils.splitPreserveAllTokens(null, *, *)            = null
7860     * StringUtils.splitPreserveAllTokens("", *, *)              = []
7861     * StringUtils.splitPreserveAllTokens("ab de fg", null, 0)   = ["ab", "de", "fg"]
7862     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 0) = ["ab", "", "", "de", "fg"]
7863     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
7864     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
7865     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 2) = ["ab", "  de fg"]
7866     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 3) = ["ab", "", " de fg"]
7867     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 4) = ["ab", "", "", "de fg"]
7868     * </pre>
7869     *
7870     * @param str  the String to parse, may be {@code null}
7871     * @param separatorChars  the characters used as the delimiters,
7872     *  {@code null} splits on whitespace
7873     * @param max  the maximum number of elements to include in the
7874     *  array. A zero or negative value implies no limit
7875     * @return an array of parsed Strings, {@code null} if null String input
7876     * @since 2.1
7877     */
7878    public static String[] splitPreserveAllTokens(final String str, final String separatorChars, final int max) {
7879        return splitWorker(str, separatorChars, max, true);
7880    }
7881
7882    /**
7883     * Performs the logic for the {@code split} and
7884     * {@code splitPreserveAllTokens} methods that do not return a
7885     * maximum array length.
7886     *
7887     * @param str  the String to parse, may be {@code null}
7888     * @param separatorChar the separate character
7889     * @param preserveAllTokens if {@code true}, adjacent separators are
7890     * treated as empty token separators; if {@code false}, adjacent
7891     * separators are treated as one separator.
7892     * @return an array of parsed Strings, {@code null} if null String input
7893     */
7894    private static String[] splitWorker(final String str, final char separatorChar, final boolean preserveAllTokens) {
7895        // Performance tuned for 2.0 (JDK1.4)
7896
7897        if (str == null) {
7898            return null;
7899        }
7900        final int len = str.length();
7901        if (len == 0) {
7902            return ArrayUtils.EMPTY_STRING_ARRAY;
7903        }
7904        final List<String> list = new ArrayList<>();
7905        int i = 0;
7906        int start = 0;
7907        boolean match = false;
7908        boolean lastMatch = false;
7909        while (i < len) {
7910            if (str.charAt(i) == separatorChar) {
7911                if (match || preserveAllTokens) {
7912                    list.add(str.substring(start, i));
7913                    match = false;
7914                    lastMatch = true;
7915                }
7916                start = ++i;
7917                continue;
7918            }
7919            lastMatch = false;
7920            match = true;
7921            i++;
7922        }
7923        if (match || preserveAllTokens && lastMatch) {
7924            list.add(str.substring(start, i));
7925        }
7926        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7927    }
7928
7929    /**
7930     * Performs the logic for the {@code split} and
7931     * {@code splitPreserveAllTokens} methods that return a maximum array
7932     * length.
7933     *
7934     * @param str  the String to parse, may be {@code null}
7935     * @param separatorChars the separate character
7936     * @param max  the maximum number of elements to include in the
7937     *  array. A zero or negative value implies no limit.
7938     * @param preserveAllTokens if {@code true}, adjacent separators are
7939     * treated as empty token separators; if {@code false}, adjacent
7940     * separators are treated as one separator.
7941     * @return an array of parsed Strings, {@code null} if null String input
7942     */
7943    private static String[] splitWorker(final String str, final String separatorChars, final int max, final boolean preserveAllTokens) {
7944        // Performance tuned for 2.0 (JDK1.4)
7945        // Direct code is quicker than StringTokenizer.
7946        // Also, StringTokenizer uses isSpace() not isWhitespace()
7947
7948        if (str == null) {
7949            return null;
7950        }
7951        final int len = str.length();
7952        if (len == 0) {
7953            return ArrayUtils.EMPTY_STRING_ARRAY;
7954        }
7955        final List<String> list = new ArrayList<>();
7956        int sizePlus1 = 1;
7957        int i = 0;
7958        int start = 0;
7959        boolean match = false;
7960        boolean lastMatch = false;
7961        if (separatorChars == null) {
7962            // Null separator means use whitespace
7963            while (i < len) {
7964                if (Character.isWhitespace(str.charAt(i))) {
7965                    if (match || preserveAllTokens) {
7966                        lastMatch = true;
7967                        if (sizePlus1++ == max) {
7968                            i = len;
7969                            lastMatch = false;
7970                        }
7971                        list.add(str.substring(start, i));
7972                        match = false;
7973                    }
7974                    start = ++i;
7975                    continue;
7976                }
7977                lastMatch = false;
7978                match = true;
7979                i++;
7980            }
7981        } else if (separatorChars.length() == 1) {
7982            // Optimise 1 character case
7983            final char sep = separatorChars.charAt(0);
7984            while (i < len) {
7985                if (str.charAt(i) == sep) {
7986                    if (match || preserveAllTokens) {
7987                        lastMatch = true;
7988                        if (sizePlus1++ == max) {
7989                            i = len;
7990                            lastMatch = false;
7991                        }
7992                        list.add(str.substring(start, i));
7993                        match = false;
7994                    }
7995                    start = ++i;
7996                    continue;
7997                }
7998                lastMatch = false;
7999                match = true;
8000                i++;
8001            }
8002        } else {
8003            // standard case
8004            while (i < len) {
8005                if (separatorChars.indexOf(str.charAt(i)) >= 0) {
8006                    if (match || preserveAllTokens) {
8007                        lastMatch = true;
8008                        if (sizePlus1++ == max) {
8009                            i = len;
8010                            lastMatch = false;
8011                        }
8012                        list.add(str.substring(start, i));
8013                        match = false;
8014                    }
8015                    start = ++i;
8016                    continue;
8017                }
8018                lastMatch = false;
8019                match = true;
8020                i++;
8021            }
8022        }
8023        if (match || preserveAllTokens && lastMatch) {
8024            list.add(str.substring(start, i));
8025        }
8026        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
8027    }
8028
8029    /**
8030     * <p>Check if a CharSequence starts with a specified prefix.</p>
8031     *
8032     * <p>{@code null}s are handled without exceptions. Two {@code null}
8033     * references are considered to be equal. The comparison is case sensitive.</p>
8034     *
8035     * <pre>
8036     * StringUtils.startsWith(null, null)      = true
8037     * StringUtils.startsWith(null, "abc")     = false
8038     * StringUtils.startsWith("abcdef", null)  = false
8039     * StringUtils.startsWith("abcdef", "abc") = true
8040     * StringUtils.startsWith("ABCDEF", "abc") = false
8041     * </pre>
8042     *
8043     * @see java.lang.String#startsWith(String)
8044     * @param str  the CharSequence to check, may be null
8045     * @param prefix the prefix to find, may be null
8046     * @return {@code true} if the CharSequence starts with the prefix, case sensitive, or
8047     *  both {@code null}
8048     * @since 2.4
8049     * @since 3.0 Changed signature from startsWith(String, String) to startsWith(CharSequence, CharSequence)
8050     */
8051    public static boolean startsWith(final CharSequence str, final CharSequence prefix) {
8052        return startsWith(str, prefix, false);
8053    }
8054
8055    /**
8056     * <p>Check if a CharSequence starts with a specified prefix (optionally case insensitive).</p>
8057     *
8058     * @see java.lang.String#startsWith(String)
8059     * @param str  the CharSequence to check, may be null
8060     * @param prefix the prefix to find, may be null
8061     * @param ignoreCase indicates whether the compare should ignore case
8062     *  (case insensitive) or not.
8063     * @return {@code true} if the CharSequence starts with the prefix or
8064     *  both {@code null}
8065     */
8066    private static boolean startsWith(final CharSequence str, final CharSequence prefix, final boolean ignoreCase) {
8067        if (str == null || prefix == null) {
8068            return str == prefix;
8069        }
8070        // Get length once instead of twice in the unlikely case that it changes.
8071        final int preLen = prefix.length();
8072        if (preLen > str.length()) {
8073            return false;
8074        }
8075        return CharSequenceUtils.regionMatches(str, ignoreCase, 0, prefix, 0, preLen);
8076    }
8077
8078    /**
8079     * <p>Check if a CharSequence starts with any of the provided case-sensitive prefixes.</p>
8080     *
8081     * <pre>
8082     * StringUtils.startsWithAny(null, null)      = false
8083     * StringUtils.startsWithAny(null, new String[] {"abc"})  = false
8084     * StringUtils.startsWithAny("abcxyz", null)     = false
8085     * StringUtils.startsWithAny("abcxyz", new String[] {""}) = true
8086     * StringUtils.startsWithAny("abcxyz", new String[] {"abc"}) = true
8087     * StringUtils.startsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
8088     * StringUtils.startsWithAny("abcxyz", null, "xyz", "ABCX") = false
8089     * StringUtils.startsWithAny("ABCXYZ", null, "xyz", "abc") = false
8090     * </pre>
8091     *
8092     * @param sequence the CharSequence to check, may be null
8093     * @param searchStrings the case-sensitive CharSequence prefixes, may be empty or contain {@code null}
8094     * @see StringUtils#startsWith(CharSequence, CharSequence)
8095     * @return {@code true} if the input {@code sequence} is {@code null} AND no {@code searchStrings} are provided, or
8096     *   the input {@code sequence} begins with any of the provided case-sensitive {@code searchStrings}.
8097     * @since 2.5
8098     * @since 3.0 Changed signature from startsWithAny(String, String[]) to startsWithAny(CharSequence, CharSequence...)
8099     */
8100    public static boolean startsWithAny(final CharSequence sequence, final CharSequence... searchStrings) {
8101        if (isEmpty(sequence) || ArrayUtils.isEmpty(searchStrings)) {
8102            return false;
8103        }
8104        for (final CharSequence searchString : searchStrings) {
8105            if (startsWith(sequence, searchString)) {
8106                return true;
8107            }
8108        }
8109        return false;
8110    }
8111
8112    /**
8113     * <p>Case insensitive check if a CharSequence starts with a specified prefix.</p>
8114     *
8115     * <p>{@code null}s are handled without exceptions. Two {@code null}
8116     * references are considered to be equal. The comparison is case insensitive.</p>
8117     *
8118     * <pre>
8119     * StringUtils.startsWithIgnoreCase(null, null)      = true
8120     * StringUtils.startsWithIgnoreCase(null, "abc")     = false
8121     * StringUtils.startsWithIgnoreCase("abcdef", null)  = false
8122     * StringUtils.startsWithIgnoreCase("abcdef", "abc") = true
8123     * StringUtils.startsWithIgnoreCase("ABCDEF", "abc") = true
8124     * </pre>
8125     *
8126     * @see java.lang.String#startsWith(String)
8127     * @param str  the CharSequence to check, may be null
8128     * @param prefix the prefix to find, may be null
8129     * @return {@code true} if the CharSequence starts with the prefix, case insensitive, or
8130     *  both {@code null}
8131     * @since 2.4
8132     * @since 3.0 Changed signature from startsWithIgnoreCase(String, String) to startsWithIgnoreCase(CharSequence, CharSequence)
8133     */
8134    public static boolean startsWithIgnoreCase(final CharSequence str, final CharSequence prefix) {
8135        return startsWith(str, prefix, true);
8136    }
8137
8138    /**
8139     * <p>Strips whitespace from the start and end of a String.</p>
8140     *
8141     * <p>This is similar to {@link #trim(String)} but removes whitespace.
8142     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8143     *
8144     * <p>A {@code null} input String returns {@code null}.</p>
8145     *
8146     * <pre>
8147     * StringUtils.strip(null)     = null
8148     * StringUtils.strip("")       = ""
8149     * StringUtils.strip("   ")    = ""
8150     * StringUtils.strip("abc")    = "abc"
8151     * StringUtils.strip("  abc")  = "abc"
8152     * StringUtils.strip("abc  ")  = "abc"
8153     * StringUtils.strip(" abc ")  = "abc"
8154     * StringUtils.strip(" ab c ") = "ab c"
8155     * </pre>
8156     *
8157     * @param str  the String to remove whitespace from, may be null
8158     * @return the stripped String, {@code null} if null String input
8159     */
8160    public static String strip(final String str) {
8161        return strip(str, null);
8162    }
8163
8164    /**
8165     * <p>Strips any of a set of characters from the start and end of a String.
8166     * This is similar to {@link String#trim()} but allows the characters
8167     * to be stripped to be controlled.</p>
8168     *
8169     * <p>A {@code null} input String returns {@code null}.
8170     * An empty string ("") input returns the empty string.</p>
8171     *
8172     * <p>If the stripChars String is {@code null}, whitespace is
8173     * stripped as defined by {@link Character#isWhitespace(char)}.
8174     * Alternatively use {@link #strip(String)}.</p>
8175     *
8176     * <pre>
8177     * StringUtils.strip(null, *)          = null
8178     * StringUtils.strip("", *)            = ""
8179     * StringUtils.strip("abc", null)      = "abc"
8180     * StringUtils.strip("  abc", null)    = "abc"
8181     * StringUtils.strip("abc  ", null)    = "abc"
8182     * StringUtils.strip(" abc ", null)    = "abc"
8183     * StringUtils.strip("  abcyx", "xyz") = "  abc"
8184     * </pre>
8185     *
8186     * @param str  the String to remove characters from, may be null
8187     * @param stripChars  the characters to remove, null treated as whitespace
8188     * @return the stripped String, {@code null} if null String input
8189     */
8190    public static String strip(String str, final String stripChars) {
8191        str = stripStart(str, stripChars);
8192        return stripEnd(str, stripChars);
8193    }
8194
8195    /**
8196     * <p>Removes diacritics (~= accents) from a string. The case will not be altered.</p>
8197     * <p>For instance, '&agrave;' will be replaced by 'a'.</p>
8198     * <p>Note that ligatures will be left as is.</p>
8199     *
8200     * <pre>
8201     * StringUtils.stripAccents(null)                = null
8202     * StringUtils.stripAccents("")                  = ""
8203     * StringUtils.stripAccents("control")           = "control"
8204     * StringUtils.stripAccents("&eacute;clair")     = "eclair"
8205     * </pre>
8206     *
8207     * @param input String to be stripped
8208     * @return input text with diacritics removed
8209     *
8210     * @since 3.0
8211     */
8212    // See also Lucene's ASCIIFoldingFilter (Lucene 2.9) that replaces accented characters by their unaccented equivalent (and uncommitted bug fix: https://issues.apache.org/jira/browse/LUCENE-1343?focusedCommentId=12858907&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12858907).
8213    public static String stripAccents(final String input) {
8214        if (input == null) {
8215            return null;
8216        }
8217        final StringBuilder decomposed = new StringBuilder(Normalizer.normalize(input, Normalizer.Form.NFD));
8218        convertRemainingAccentCharacters(decomposed);
8219        // Note that this doesn't correctly remove ligatures...
8220        return STRIP_ACCENTS_PATTERN.matcher(decomposed).replaceAll(EMPTY);
8221    }
8222
8223    /**
8224     * <p>Strips whitespace from the start and end of every String in an array.
8225     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8226     *
8227     * <p>A new array is returned each time, except for length zero.
8228     * A {@code null} array will return {@code null}.
8229     * An empty array will return itself.
8230     * A {@code null} array entry will be ignored.</p>
8231     *
8232     * <pre>
8233     * StringUtils.stripAll(null)             = null
8234     * StringUtils.stripAll([])               = []
8235     * StringUtils.stripAll(["abc", "  abc"]) = ["abc", "abc"]
8236     * StringUtils.stripAll(["abc  ", null])  = ["abc", null]
8237     * </pre>
8238     *
8239     * @param strs  the array to remove whitespace from, may be null
8240     * @return the stripped Strings, {@code null} if null array input
8241     */
8242    public static String[] stripAll(final String... strs) {
8243        return stripAll(strs, null);
8244    }
8245
8246    /**
8247     * <p>Strips any of a set of characters from the start and end of every
8248     * String in an array.</p>
8249     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8250     *
8251     * <p>A new array is returned each time, except for length zero.
8252     * A {@code null} array will return {@code null}.
8253     * An empty array will return itself.
8254     * A {@code null} array entry will be ignored.
8255     * A {@code null} stripChars will strip whitespace as defined by
8256     * {@link Character#isWhitespace(char)}.</p>
8257     *
8258     * <pre>
8259     * StringUtils.stripAll(null, *)                = null
8260     * StringUtils.stripAll([], *)                  = []
8261     * StringUtils.stripAll(["abc", "  abc"], null) = ["abc", "abc"]
8262     * StringUtils.stripAll(["abc  ", null], null)  = ["abc", null]
8263     * StringUtils.stripAll(["abc  ", null], "yz")  = ["abc  ", null]
8264     * StringUtils.stripAll(["yabcz", null], "yz")  = ["abc", null]
8265     * </pre>
8266     *
8267     * @param strs  the array to remove characters from, may be null
8268     * @param stripChars  the characters to remove, null treated as whitespace
8269     * @return the stripped Strings, {@code null} if null array input
8270     */
8271    public static String[] stripAll(final String[] strs, final String stripChars) {
8272        final int strsLen = ArrayUtils.getLength(strs);
8273        if (strsLen == 0) {
8274            return strs;
8275        }
8276        final String[] newArr = new String[strsLen];
8277        for (int i = 0; i < strsLen; i++) {
8278            newArr[i] = strip(strs[i], stripChars);
8279        }
8280        return newArr;
8281    }
8282
8283    /**
8284     * <p>Strips any of a set of characters from the end of a String.</p>
8285     *
8286     * <p>A {@code null} input String returns {@code null}.
8287     * An empty string ("") input returns the empty string.</p>
8288     *
8289     * <p>If the stripChars String is {@code null}, whitespace is
8290     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
8291     *
8292     * <pre>
8293     * StringUtils.stripEnd(null, *)          = null
8294     * StringUtils.stripEnd("", *)            = ""
8295     * StringUtils.stripEnd("abc", "")        = "abc"
8296     * StringUtils.stripEnd("abc", null)      = "abc"
8297     * StringUtils.stripEnd("  abc", null)    = "  abc"
8298     * StringUtils.stripEnd("abc  ", null)    = "abc"
8299     * StringUtils.stripEnd(" abc ", null)    = " abc"
8300     * StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
8301     * StringUtils.stripEnd("120.00", ".0")   = "12"
8302     * </pre>
8303     *
8304     * @param str  the String to remove characters from, may be null
8305     * @param stripChars  the set of characters to remove, null treated as whitespace
8306     * @return the stripped String, {@code null} if null String input
8307     */
8308    public static String stripEnd(final String str, final String stripChars) {
8309        int end = length(str);
8310        if (end == 0) {
8311            return str;
8312        }
8313
8314        if (stripChars == null) {
8315            while (end != 0 && Character.isWhitespace(str.charAt(end - 1))) {
8316                end--;
8317            }
8318        } else if (stripChars.isEmpty()) {
8319            return str;
8320        } else {
8321            while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
8322                end--;
8323            }
8324        }
8325        return str.substring(0, end);
8326    }
8327
8328    /**
8329     * <p>Strips any of a set of characters from the start of a String.</p>
8330     *
8331     * <p>A {@code null} input String returns {@code null}.
8332     * An empty string ("") input returns the empty string.</p>
8333     *
8334     * <p>If the stripChars String is {@code null}, whitespace is
8335     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
8336     *
8337     * <pre>
8338     * StringUtils.stripStart(null, *)          = null
8339     * StringUtils.stripStart("", *)            = ""
8340     * StringUtils.stripStart("abc", "")        = "abc"
8341     * StringUtils.stripStart("abc", null)      = "abc"
8342     * StringUtils.stripStart("  abc", null)    = "abc"
8343     * StringUtils.stripStart("abc  ", null)    = "abc  "
8344     * StringUtils.stripStart(" abc ", null)    = "abc "
8345     * StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
8346     * </pre>
8347     *
8348     * @param str  the String to remove characters from, may be null
8349     * @param stripChars  the characters to remove, null treated as whitespace
8350     * @return the stripped String, {@code null} if null String input
8351     */
8352    public static String stripStart(final String str, final String stripChars) {
8353        final int strLen = length(str);
8354        if (strLen == 0) {
8355            return str;
8356        }
8357        int start = 0;
8358        if (stripChars == null) {
8359            while (start != strLen && Character.isWhitespace(str.charAt(start))) {
8360                start++;
8361            }
8362        } else if (stripChars.isEmpty()) {
8363            return str;
8364        } else {
8365            while (start != strLen && stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND) {
8366                start++;
8367            }
8368        }
8369        return str.substring(start);
8370    }
8371
8372    /**
8373     * <p>Strips whitespace from the start and end of a String  returning
8374     * an empty String if {@code null} input.</p>
8375     *
8376     * <p>This is similar to {@link #trimToEmpty(String)} but removes whitespace.
8377     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8378     *
8379     * <pre>
8380     * StringUtils.stripToEmpty(null)     = ""
8381     * StringUtils.stripToEmpty("")       = ""
8382     * StringUtils.stripToEmpty("   ")    = ""
8383     * StringUtils.stripToEmpty("abc")    = "abc"
8384     * StringUtils.stripToEmpty("  abc")  = "abc"
8385     * StringUtils.stripToEmpty("abc  ")  = "abc"
8386     * StringUtils.stripToEmpty(" abc ")  = "abc"
8387     * StringUtils.stripToEmpty(" ab c ") = "ab c"
8388     * </pre>
8389     *
8390     * @param str  the String to be stripped, may be null
8391     * @return the trimmed String, or an empty String if {@code null} input
8392     * @since 2.0
8393     */
8394    public static String stripToEmpty(final String str) {
8395        return str == null ? EMPTY : strip(str, null);
8396    }
8397
8398    /**
8399     * <p>Strips whitespace from the start and end of a String  returning
8400     * {@code null} if the String is empty ("") after the strip.</p>
8401     *
8402     * <p>This is similar to {@link #trimToNull(String)} but removes whitespace.
8403     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8404     *
8405     * <pre>
8406     * StringUtils.stripToNull(null)     = null
8407     * StringUtils.stripToNull("")       = null
8408     * StringUtils.stripToNull("   ")    = null
8409     * StringUtils.stripToNull("abc")    = "abc"
8410     * StringUtils.stripToNull("  abc")  = "abc"
8411     * StringUtils.stripToNull("abc  ")  = "abc"
8412     * StringUtils.stripToNull(" abc ")  = "abc"
8413     * StringUtils.stripToNull(" ab c ") = "ab c"
8414     * </pre>
8415     *
8416     * @param str  the String to be stripped, may be null
8417     * @return the stripped String,
8418     *  {@code null} if whitespace, empty or null String input
8419     * @since 2.0
8420     */
8421    public static String stripToNull(String str) {
8422        if (str == null) {
8423            return null;
8424        }
8425        str = strip(str, null);
8426        return str.isEmpty() ? null : str; // NOSONARLINT str cannot be null here
8427    }
8428
8429    /**
8430     * <p>Gets a substring from the specified String avoiding exceptions.</p>
8431     *
8432     * <p>A negative start position can be used to start {@code n}
8433     * characters from the end of the String.</p>
8434     *
8435     * <p>A {@code null} String will return {@code null}.
8436     * An empty ("") String will return "".</p>
8437     *
8438     * <pre>
8439     * StringUtils.substring(null, *)   = null
8440     * StringUtils.substring("", *)     = ""
8441     * StringUtils.substring("abc", 0)  = "abc"
8442     * StringUtils.substring("abc", 2)  = "c"
8443     * StringUtils.substring("abc", 4)  = ""
8444     * StringUtils.substring("abc", -2) = "bc"
8445     * StringUtils.substring("abc", -4) = "abc"
8446     * </pre>
8447     *
8448     * @param str  the String to get the substring from, may be null
8449     * @param start  the position to start from, negative means
8450     *  count back from the end of the String by this many characters
8451     * @return substring from start position, {@code null} if null String input
8452     */
8453    public static String substring(final String str, int start) {
8454        if (str == null) {
8455            return null;
8456        }
8457
8458        // handle negatives, which means last n characters
8459        if (start < 0) {
8460            start = str.length() + start; // remember start is negative
8461        }
8462
8463        if (start < 0) {
8464            start = 0;
8465        }
8466        if (start > str.length()) {
8467            return EMPTY;
8468        }
8469
8470        return str.substring(start);
8471    }
8472
8473    /**
8474     * <p>Gets a substring from the specified String avoiding exceptions.</p>
8475     *
8476     * <p>A negative start position can be used to start/end {@code n}
8477     * characters from the end of the String.</p>
8478     *
8479     * <p>The returned substring starts with the character in the {@code start}
8480     * position and ends before the {@code end} position. All position counting is
8481     * zero-based -- i.e., to start at the beginning of the string use
8482     * {@code start = 0}. Negative start and end positions can be used to
8483     * specify offsets relative to the end of the String.</p>
8484     *
8485     * <p>If {@code start} is not strictly to the left of {@code end}, ""
8486     * is returned.</p>
8487     *
8488     * <pre>
8489     * StringUtils.substring(null, *, *)    = null
8490     * StringUtils.substring("", * ,  *)    = "";
8491     * StringUtils.substring("abc", 0, 2)   = "ab"
8492     * StringUtils.substring("abc", 2, 0)   = ""
8493     * StringUtils.substring("abc", 2, 4)   = "c"
8494     * StringUtils.substring("abc", 4, 6)   = ""
8495     * StringUtils.substring("abc", 2, 2)   = ""
8496     * StringUtils.substring("abc", -2, -1) = "b"
8497     * StringUtils.substring("abc", -4, 2)  = "ab"
8498     * </pre>
8499     *
8500     * @param str  the String to get the substring from, may be null
8501     * @param start  the position to start from, negative means
8502     *  count back from the end of the String by this many characters
8503     * @param end  the position to end at (exclusive), negative means
8504     *  count back from the end of the String by this many characters
8505     * @return substring from start position to end position,
8506     *  {@code null} if null String input
8507     */
8508    public static String substring(final String str, int start, int end) {
8509        if (str == null) {
8510            return null;
8511        }
8512
8513        // handle negatives
8514        if (end < 0) {
8515            end = str.length() + end; // remember end is negative
8516        }
8517        if (start < 0) {
8518            start = str.length() + start; // remember start is negative
8519        }
8520
8521        // check length next
8522        if (end > str.length()) {
8523            end = str.length();
8524        }
8525
8526        // if start is greater than end, return ""
8527        if (start > end) {
8528            return EMPTY;
8529        }
8530
8531        if (start < 0) {
8532            start = 0;
8533        }
8534        if (end < 0) {
8535            end = 0;
8536        }
8537
8538        return str.substring(start, end);
8539    }
8540
8541    /**
8542     * <p>Gets the substring after the first occurrence of a separator.
8543     * The separator is not returned.</p>
8544     *
8545     * <p>A {@code null} string input will return {@code null}.
8546     * An empty ("") string input will return the empty string.
8547     *
8548     * <p>If nothing is found, the empty string is returned.</p>
8549     *
8550     * <pre>
8551     * StringUtils.substringAfter(null, *)      = null
8552     * StringUtils.substringAfter("", *)        = ""
8553     * StringUtils.substringAfter("abc", 'a')   = "bc"
8554     * StringUtils.substringAfter("abcba", 'b') = "cba"
8555     * StringUtils.substringAfter("abc", 'c')   = ""
8556     * StringUtils.substringAfter("abc", 'd')   = ""
8557     * StringUtils.substringAfter(" abc", 32)   = "abc"
8558     * </pre>
8559     *
8560     * @param str  the String to get a substring from, may be null
8561     * @param separator  the character to search.
8562     * @return the substring after the first occurrence of the separator,
8563     *  {@code null} if null String input
8564     * @since 3.11
8565     */
8566    public static String substringAfter(final String str, final int separator) {
8567        if (isEmpty(str)) {
8568            return str;
8569        }
8570        final int pos = str.indexOf(separator);
8571        if (pos == INDEX_NOT_FOUND) {
8572            return EMPTY;
8573        }
8574        return str.substring(pos + 1);
8575    }
8576
8577    /**
8578     * <p>Gets the substring after the first occurrence of a separator.
8579     * The separator is not returned.</p>
8580     *
8581     * <p>A {@code null} string input will return {@code null}.
8582     * An empty ("") string input will return the empty string.
8583     * A {@code null} separator will return the empty string if the
8584     * input string is not {@code null}.</p>
8585     *
8586     * <p>If nothing is found, the empty string is returned.</p>
8587     *
8588     * <pre>
8589     * StringUtils.substringAfter(null, *)      = null
8590     * StringUtils.substringAfter("", *)        = ""
8591     * StringUtils.substringAfter(*, null)      = ""
8592     * StringUtils.substringAfter("abc", "a")   = "bc"
8593     * StringUtils.substringAfter("abcba", "b") = "cba"
8594     * StringUtils.substringAfter("abc", "c")   = ""
8595     * StringUtils.substringAfter("abc", "d")   = ""
8596     * StringUtils.substringAfter("abc", "")    = "abc"
8597     * </pre>
8598     *
8599     * @param str  the String to get a substring from, may be null
8600     * @param separator  the String to search for, may be null
8601     * @return the substring after the first occurrence of the separator,
8602     *  {@code null} if null String input
8603     * @since 2.0
8604     */
8605    public static String substringAfter(final String str, final String separator) {
8606        if (isEmpty(str)) {
8607            return str;
8608        }
8609        if (separator == null) {
8610            return EMPTY;
8611        }
8612        final int pos = str.indexOf(separator);
8613        if (pos == INDEX_NOT_FOUND) {
8614            return EMPTY;
8615        }
8616        return str.substring(pos + separator.length());
8617    }
8618
8619    /**
8620     * <p>Gets the substring after the last occurrence of a separator.
8621     * The separator is not returned.</p>
8622     *
8623     * <p>A {@code null} string input will return {@code null}.
8624     * An empty ("") string input will return the empty string.
8625     *
8626     * <p>If nothing is found, the empty string is returned.</p>
8627     *
8628     * <pre>
8629     * StringUtils.substringAfterLast(null, *)      = null
8630     * StringUtils.substringAfterLast("", *)        = ""
8631     * StringUtils.substringAfterLast("abc", 'a')   = "bc"
8632     * StringUtils.substringAfterLast(" bc", 32)    = "bc"
8633     * StringUtils.substringAfterLast("abcba", 'b') = "a"
8634     * StringUtils.substringAfterLast("abc", 'c')   = ""
8635     * StringUtils.substringAfterLast("a", 'a')     = ""
8636     * StringUtils.substringAfterLast("a", 'z')     = ""
8637     * </pre>
8638     *
8639     * @param str  the String to get a substring from, may be null
8640     * @param separator  the String to search for, may be null
8641     * @return the substring after the last occurrence of the separator,
8642     *  {@code null} if null String input
8643     * @since 3.11
8644     */
8645    public static String substringAfterLast(final String str, final int separator) {
8646        if (isEmpty(str)) {
8647            return str;
8648        }
8649        final int pos = str.lastIndexOf(separator);
8650        if (pos == INDEX_NOT_FOUND || pos == str.length() - 1) {
8651            return EMPTY;
8652        }
8653        return str.substring(pos + 1);
8654    }
8655
8656    /**
8657     * <p>Gets the substring after the last occurrence of a separator.
8658     * The separator is not returned.</p>
8659     *
8660     * <p>A {@code null} string input will return {@code null}.
8661     * An empty ("") string input will return the empty string.
8662     * An empty or {@code null} separator will return the empty string if
8663     * the input string is not {@code null}.</p>
8664     *
8665     * <p>If nothing is found, the empty string is returned.</p>
8666     *
8667     * <pre>
8668     * StringUtils.substringAfterLast(null, *)      = null
8669     * StringUtils.substringAfterLast("", *)        = ""
8670     * StringUtils.substringAfterLast(*, "")        = ""
8671     * StringUtils.substringAfterLast(*, null)      = ""
8672     * StringUtils.substringAfterLast("abc", "a")   = "bc"
8673     * StringUtils.substringAfterLast("abcba", "b") = "a"
8674     * StringUtils.substringAfterLast("abc", "c")   = ""
8675     * StringUtils.substringAfterLast("a", "a")     = ""
8676     * StringUtils.substringAfterLast("a", "z")     = ""
8677     * </pre>
8678     *
8679     * @param str  the String to get a substring from, may be null
8680     * @param separator  the String to search for, may be null
8681     * @return the substring after the last occurrence of the separator,
8682     *  {@code null} if null String input
8683     * @since 2.0
8684     */
8685    public static String substringAfterLast(final String str, final String separator) {
8686        if (isEmpty(str)) {
8687            return str;
8688        }
8689        if (isEmpty(separator)) {
8690            return EMPTY;
8691        }
8692        final int pos = str.lastIndexOf(separator);
8693        if (pos == INDEX_NOT_FOUND || pos == str.length() - separator.length()) {
8694            return EMPTY;
8695        }
8696        return str.substring(pos + separator.length());
8697    }
8698
8699    /**
8700     * <p>
8701     * Gets the substring before the first occurrence of a separator. The separator is not returned.
8702     * </p>
8703     *
8704     * <p>
8705     * A {@code null} string input will return {@code null}. An empty ("") string input will return the empty string.
8706     * </p>
8707     *
8708     * <p>
8709     * If nothing is found, the string input is returned.
8710     * </p>
8711     *
8712     * <pre>
8713     * StringUtils.substringBefore(null, *)      = null
8714     * StringUtils.substringBefore("", *)        = ""
8715     * StringUtils.substringBefore("abc", 'a')   = ""
8716     * StringUtils.substringBefore("abcba", 'b') = "a"
8717     * StringUtils.substringBefore("abc", 'c')   = "ab"
8718     * StringUtils.substringBefore("abc", 'd')   = "abc"
8719     * </pre>
8720     *
8721     * @param str the String to get a substring from, may be null
8722     * @param separator the String to search for, may be null
8723     * @return the substring before the first occurrence of the separator, {@code null} if null String input
8724     * @since 3.12.0
8725     */
8726    public static String substringBefore(final String str, final int separator) {
8727        if (isEmpty(str)) {
8728            return str;
8729        }
8730        final int pos = str.indexOf(separator);
8731        if (pos == INDEX_NOT_FOUND) {
8732            return str;
8733        }
8734        return str.substring(0, pos);
8735    }
8736
8737    /**
8738     * <p>Gets the substring before the first occurrence of a separator.
8739     * The separator is not returned.</p>
8740     *
8741     * <p>A {@code null} string input will return {@code null}.
8742     * An empty ("") string input will return the empty string.
8743     * A {@code null} separator will return the input string.</p>
8744     *
8745     * <p>If nothing is found, the string input is returned.</p>
8746     *
8747     * <pre>
8748     * StringUtils.substringBefore(null, *)      = null
8749     * StringUtils.substringBefore("", *)        = ""
8750     * StringUtils.substringBefore("abc", "a")   = ""
8751     * StringUtils.substringBefore("abcba", "b") = "a"
8752     * StringUtils.substringBefore("abc", "c")   = "ab"
8753     * StringUtils.substringBefore("abc", "d")   = "abc"
8754     * StringUtils.substringBefore("abc", "")    = ""
8755     * StringUtils.substringBefore("abc", null)  = "abc"
8756     * </pre>
8757     *
8758     * @param str  the String to get a substring from, may be null
8759     * @param separator  the String to search for, may be null
8760     * @return the substring before the first occurrence of the separator,
8761     *  {@code null} if null String input
8762     * @since 2.0
8763     */
8764    public static String substringBefore(final String str, final String separator) {
8765        if (isEmpty(str) || separator == null) {
8766            return str;
8767        }
8768        if (separator.isEmpty()) {
8769            return EMPTY;
8770        }
8771        final int pos = str.indexOf(separator);
8772        if (pos == INDEX_NOT_FOUND) {
8773            return str;
8774        }
8775        return str.substring(0, pos);
8776    }
8777
8778    /**
8779     * <p>Gets the substring before the last occurrence of a separator.
8780     * The separator is not returned.</p>
8781     *
8782     * <p>A {@code null} string input will return {@code null}.
8783     * An empty ("") string input will return the empty string.
8784     * An empty or {@code null} separator will return the input string.</p>
8785     *
8786     * <p>If nothing is found, the string input is returned.</p>
8787     *
8788     * <pre>
8789     * StringUtils.substringBeforeLast(null, *)      = null
8790     * StringUtils.substringBeforeLast("", *)        = ""
8791     * StringUtils.substringBeforeLast("abcba", "b") = "abc"
8792     * StringUtils.substringBeforeLast("abc", "c")   = "ab"
8793     * StringUtils.substringBeforeLast("a", "a")     = ""
8794     * StringUtils.substringBeforeLast("a", "z")     = "a"
8795     * StringUtils.substringBeforeLast("a", null)    = "a"
8796     * StringUtils.substringBeforeLast("a", "")      = "a"
8797     * </pre>
8798     *
8799     * @param str  the String to get a substring from, may be null
8800     * @param separator  the String to search for, may be null
8801     * @return the substring before the last occurrence of the separator,
8802     *  {@code null} if null String input
8803     * @since 2.0
8804     */
8805    public static String substringBeforeLast(final String str, final String separator) {
8806        if (isEmpty(str) || isEmpty(separator)) {
8807            return str;
8808        }
8809        final int pos = str.lastIndexOf(separator);
8810        if (pos == INDEX_NOT_FOUND) {
8811            return str;
8812        }
8813        return str.substring(0, pos);
8814    }
8815
8816    /**
8817     * <p>Gets the String that is nested in between two instances of the
8818     * same String.</p>
8819     *
8820     * <p>A {@code null} input String returns {@code null}.
8821     * A {@code null} tag returns {@code null}.</p>
8822     *
8823     * <pre>
8824     * StringUtils.substringBetween(null, *)            = null
8825     * StringUtils.substringBetween("", "")             = ""
8826     * StringUtils.substringBetween("", "tag")          = null
8827     * StringUtils.substringBetween("tagabctag", null)  = null
8828     * StringUtils.substringBetween("tagabctag", "")    = ""
8829     * StringUtils.substringBetween("tagabctag", "tag") = "abc"
8830     * </pre>
8831     *
8832     * @param str  the String containing the substring, may be null
8833     * @param tag  the String before and after the substring, may be null
8834     * @return the substring, {@code null} if no match
8835     * @since 2.0
8836     */
8837    public static String substringBetween(final String str, final String tag) {
8838        return substringBetween(str, tag, tag);
8839    }
8840
8841    /**
8842     * <p>Gets the String that is nested in between two Strings.
8843     * Only the first match is returned.</p>
8844     *
8845     * <p>A {@code null} input String returns {@code null}.
8846     * A {@code null} open/close returns {@code null} (no match).
8847     * An empty ("") open and close returns an empty string.</p>
8848     *
8849     * <pre>
8850     * StringUtils.substringBetween("wx[b]yz", "[", "]") = "b"
8851     * StringUtils.substringBetween(null, *, *)          = null
8852     * StringUtils.substringBetween(*, null, *)          = null
8853     * StringUtils.substringBetween(*, *, null)          = null
8854     * StringUtils.substringBetween("", "", "")          = ""
8855     * StringUtils.substringBetween("", "", "]")         = null
8856     * StringUtils.substringBetween("", "[", "]")        = null
8857     * StringUtils.substringBetween("yabcz", "", "")     = ""
8858     * StringUtils.substringBetween("yabcz", "y", "z")   = "abc"
8859     * StringUtils.substringBetween("yabczyabcz", "y", "z")   = "abc"
8860     * </pre>
8861     *
8862     * @param str  the String containing the substring, may be null
8863     * @param open  the String before the substring, may be null
8864     * @param close  the String after the substring, may be null
8865     * @return the substring, {@code null} if no match
8866     * @since 2.0
8867     */
8868    public static String substringBetween(final String str, final String open, final String close) {
8869        if (!ObjectUtils.allNotNull(str, open, close)) {
8870            return null;
8871        }
8872        final int start = str.indexOf(open);
8873        if (start != INDEX_NOT_FOUND) {
8874            final int end = str.indexOf(close, start + open.length());
8875            if (end != INDEX_NOT_FOUND) {
8876                return str.substring(start + open.length(), end);
8877            }
8878        }
8879        return null;
8880    }
8881
8882    /**
8883     * <p>Searches a String for substrings delimited by a start and end tag,
8884     * returning all matching substrings in an array.</p>
8885     *
8886     * <p>A {@code null} input String returns {@code null}.
8887     * A {@code null} open/close returns {@code null} (no match).
8888     * An empty ("") open/close returns {@code null} (no match).</p>
8889     *
8890     * <pre>
8891     * StringUtils.substringsBetween("[a][b][c]", "[", "]") = ["a","b","c"]
8892     * StringUtils.substringsBetween(null, *, *)            = null
8893     * StringUtils.substringsBetween(*, null, *)            = null
8894     * StringUtils.substringsBetween(*, *, null)            = null
8895     * StringUtils.substringsBetween("", "[", "]")          = []
8896     * </pre>
8897     *
8898     * @param str  the String containing the substrings, null returns null, empty returns empty
8899     * @param open  the String identifying the start of the substring, empty returns null
8900     * @param close  the String identifying the end of the substring, empty returns null
8901     * @return a String Array of substrings, or {@code null} if no match
8902     * @since 2.3
8903     */
8904    public static String[] substringsBetween(final String str, final String open, final String close) {
8905        if (str == null || isEmpty(open) || isEmpty(close)) {
8906            return null;
8907        }
8908        final int strLen = str.length();
8909        if (strLen == 0) {
8910            return ArrayUtils.EMPTY_STRING_ARRAY;
8911        }
8912        final int closeLen = close.length();
8913        final int openLen = open.length();
8914        final List<String> list = new ArrayList<>();
8915        int pos = 0;
8916        while (pos < strLen - closeLen) {
8917            int start = str.indexOf(open, pos);
8918            if (start < 0) {
8919                break;
8920            }
8921            start += openLen;
8922            final int end = str.indexOf(close, start);
8923            if (end < 0) {
8924                break;
8925            }
8926            list.add(str.substring(start, end));
8927            pos = end + closeLen;
8928        }
8929        if (list.isEmpty()) {
8930            return null;
8931        }
8932        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
8933    }
8934
8935    /**
8936     * <p>Swaps the case of a String changing upper and title case to
8937     * lower case, and lower case to upper case.</p>
8938     *
8939     * <ul>
8940     *  <li>Upper case character converts to Lower case</li>
8941     *  <li>Title case character converts to Lower case</li>
8942     *  <li>Lower case character converts to Upper case</li>
8943     * </ul>
8944     *
8945     * <p>For a word based algorithm, see {@link org.apache.commons.lang3.text.WordUtils#swapCase(String)}.
8946     * A {@code null} input String returns {@code null}.</p>
8947     *
8948     * <pre>
8949     * StringUtils.swapCase(null)                 = null
8950     * StringUtils.swapCase("")                   = ""
8951     * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
8952     * </pre>
8953     *
8954     * <p>NOTE: This method changed in Lang version 2.0.
8955     * It no longer performs a word based algorithm.
8956     * If you only use ASCII, you will notice no change.
8957     * That functionality is available in org.apache.commons.lang3.text.WordUtils.</p>
8958     *
8959     * @param str  the String to swap case, may be null
8960     * @return the changed String, {@code null} if null String input
8961     */
8962    public static String swapCase(final String str) {
8963        if (isEmpty(str)) {
8964            return str;
8965        }
8966
8967        final int strLen = str.length();
8968        final int[] newCodePoints = new int[strLen]; // cannot be longer than the char array
8969        int outOffset = 0;
8970        for (int i = 0; i < strLen; ) {
8971            final int oldCodepoint = str.codePointAt(i);
8972            final int newCodePoint;
8973            if (Character.isUpperCase(oldCodepoint) || Character.isTitleCase(oldCodepoint)) {
8974                newCodePoint = Character.toLowerCase(oldCodepoint);
8975            } else if (Character.isLowerCase(oldCodepoint)) {
8976                newCodePoint = Character.toUpperCase(oldCodepoint);
8977            } else {
8978                newCodePoint = oldCodepoint;
8979            }
8980            newCodePoints[outOffset++] = newCodePoint;
8981            i += Character.charCount(newCodePoint);
8982         }
8983        return new String(newCodePoints, 0, outOffset);
8984    }
8985
8986    /**
8987     * <p>Converts a {@code CharSequence} into an array of code points.</p>
8988     *
8989     * <p>Valid pairs of surrogate code units will be converted into a single supplementary
8990     * code point. Isolated surrogate code units (i.e. a high surrogate not followed by a low surrogate or
8991     * a low surrogate not preceded by a high surrogate) will be returned as-is.</p>
8992     *
8993     * <pre>
8994     * StringUtils.toCodePoints(null)   =  null
8995     * StringUtils.toCodePoints("")     =  []  // empty array
8996     * </pre>
8997     *
8998     * @param cs the character sequence to convert
8999     * @return an array of code points
9000     * @since 3.6
9001     */
9002    public static int[] toCodePoints(final CharSequence cs) {
9003        if (cs == null) {
9004            return null;
9005        }
9006        if (cs.length() == 0) {
9007            return ArrayUtils.EMPTY_INT_ARRAY;
9008        }
9009
9010        final String s = cs.toString();
9011        final int[] result = new int[s.codePointCount(0, s.length())];
9012        int index = 0;
9013        for (int i = 0; i < result.length; i++) {
9014            result[i] = s.codePointAt(index);
9015            index += Character.charCount(result[i]);
9016        }
9017        return result;
9018    }
9019
9020    /**
9021     * Converts a {@code byte[]} to a String using the specified character encoding.
9022     *
9023     * @param bytes
9024     *            the byte array to read from
9025     * @param charset
9026     *            the encoding to use, if null then use the platform default
9027     * @return a new String
9028     * @throws NullPointerException
9029     *             if {@code bytes} is null
9030     * @since 3.2
9031     * @since 3.3 No longer throws {@link UnsupportedEncodingException}.
9032     */
9033    public static String toEncodedString(final byte[] bytes, final Charset charset) {
9034        return new String(bytes, Charsets.toCharset(charset));
9035    }
9036
9037    /**
9038     * Converts the given source String as a lower-case using the {@link Locale#ROOT} locale in a null-safe manner.
9039     *
9040     * @param source A source String or null.
9041     * @return the given source String as a lower-case using the {@link Locale#ROOT} locale or null.
9042     * @since 3.10
9043     */
9044    public static String toRootLowerCase(final String source) {
9045        return source == null ? null : source.toLowerCase(Locale.ROOT);
9046    }
9047
9048    /**
9049     * Converts the given source String as a upper-case using the {@link Locale#ROOT} locale in a null-safe manner.
9050     *
9051     * @param source A source String or null.
9052     * @return the given source String as a upper-case using the {@link Locale#ROOT} locale or null.
9053     * @since 3.10
9054     */
9055    public static String toRootUpperCase(final String source) {
9056        return source == null ? null : source.toUpperCase(Locale.ROOT);
9057    }
9058
9059    /**
9060     * Converts a {@code byte[]} to a String using the specified character encoding.
9061     *
9062     * @param bytes
9063     *            the byte array to read from
9064     * @param charsetName
9065     *            the encoding to use, if null then use the platform default
9066     * @return a new String
9067     * @throws UnsupportedEncodingException
9068     *             If the named charset is not supported
9069     * @throws NullPointerException
9070     *             if the input is null
9071     * @deprecated use {@link StringUtils#toEncodedString(byte[], Charset)} instead of String constants in your code
9072     * @since 3.1
9073     */
9074    @Deprecated
9075    public static String toString(final byte[] bytes, final String charsetName) throws UnsupportedEncodingException {
9076        return new String(bytes, Charsets.toCharset(charsetName));
9077    }
9078
9079    private static String toStringOrEmpty(final Object obj) {
9080        return Objects.toString(obj, EMPTY);
9081    }
9082
9083    /**
9084     * <p>Removes control characters (char &lt;= 32) from both
9085     * ends of this String, handling {@code null} by returning
9086     * {@code null}.</p>
9087     *
9088     * <p>The String is trimmed using {@link String#trim()}.
9089     * Trim removes start and end characters &lt;= 32.
9090     * To strip whitespace use {@link #strip(String)}.</p>
9091     *
9092     * <p>To trim your choice of characters, use the
9093     * {@link #strip(String, String)} methods.</p>
9094     *
9095     * <pre>
9096     * StringUtils.trim(null)          = null
9097     * StringUtils.trim("")            = ""
9098     * StringUtils.trim("     ")       = ""
9099     * StringUtils.trim("abc")         = "abc"
9100     * StringUtils.trim("    abc    ") = "abc"
9101     * </pre>
9102     *
9103     * @param str  the String to be trimmed, may be null
9104     * @return the trimmed string, {@code null} if null String input
9105     */
9106    public static String trim(final String str) {
9107        return str == null ? null : str.trim();
9108    }
9109
9110    /**
9111     * <p>Removes control characters (char &lt;= 32) from both
9112     * ends of this String returning an empty String ("") if the String
9113     * is empty ("") after the trim or if it is {@code null}.
9114     *
9115     * <p>The String is trimmed using {@link String#trim()}.
9116     * Trim removes start and end characters &lt;= 32.
9117     * To strip whitespace use {@link #stripToEmpty(String)}.</p>
9118     *
9119     * <pre>
9120     * StringUtils.trimToEmpty(null)          = ""
9121     * StringUtils.trimToEmpty("")            = ""
9122     * StringUtils.trimToEmpty("     ")       = ""
9123     * StringUtils.trimToEmpty("abc")         = "abc"
9124     * StringUtils.trimToEmpty("    abc    ") = "abc"
9125     * </pre>
9126     *
9127     * @param str  the String to be trimmed, may be null
9128     * @return the trimmed String, or an empty String if {@code null} input
9129     * @since 2.0
9130     */
9131    public static String trimToEmpty(final String str) {
9132        return str == null ? EMPTY : str.trim();
9133    }
9134
9135    /**
9136     * <p>Removes control characters (char &lt;= 32) from both
9137     * ends of this String returning {@code null} if the String is
9138     * empty ("") after the trim or if it is {@code null}.
9139     *
9140     * <p>The String is trimmed using {@link String#trim()}.
9141     * Trim removes start and end characters &lt;= 32.
9142     * To strip whitespace use {@link #stripToNull(String)}.</p>
9143     *
9144     * <pre>
9145     * StringUtils.trimToNull(null)          = null
9146     * StringUtils.trimToNull("")            = null
9147     * StringUtils.trimToNull("     ")       = null
9148     * StringUtils.trimToNull("abc")         = "abc"
9149     * StringUtils.trimToNull("    abc    ") = "abc"
9150     * </pre>
9151     *
9152     * @param str  the String to be trimmed, may be null
9153     * @return the trimmed String,
9154     *  {@code null} if only chars &lt;= 32, empty or null String input
9155     * @since 2.0
9156     */
9157    public static String trimToNull(final String str) {
9158        final String ts = trim(str);
9159        return isEmpty(ts) ? null : ts;
9160    }
9161
9162    /**
9163     * <p>Truncates a String. This will turn
9164     * "Now is the time for all good men" into "Now is the time for".</p>
9165     *
9166     * <p>Specifically:</p>
9167     * <ul>
9168     *   <li>If {@code str} is less than {@code maxWidth} characters
9169     *       long, return it.</li>
9170     *   <li>Else truncate it to {@code substring(str, 0, maxWidth)}.</li>
9171     *   <li>If {@code maxWidth} is less than {@code 0}, throw an
9172     *       {@code IllegalArgumentException}.</li>
9173     *   <li>In no case will it return a String of length greater than
9174     *       {@code maxWidth}.</li>
9175     * </ul>
9176     *
9177     * <pre>
9178     * StringUtils.truncate(null, 0)       = null
9179     * StringUtils.truncate(null, 2)       = null
9180     * StringUtils.truncate("", 4)         = ""
9181     * StringUtils.truncate("abcdefg", 4)  = "abcd"
9182     * StringUtils.truncate("abcdefg", 6)  = "abcdef"
9183     * StringUtils.truncate("abcdefg", 7)  = "abcdefg"
9184     * StringUtils.truncate("abcdefg", 8)  = "abcdefg"
9185     * StringUtils.truncate("abcdefg", -1) = throws an IllegalArgumentException
9186     * </pre>
9187     *
9188     * @param str  the String to truncate, may be null
9189     * @param maxWidth  maximum length of result String, must be positive
9190     * @return truncated String, {@code null} if null String input
9191     * @throws IllegalArgumentException If {@code maxWidth} is less than {@code 0}
9192     * @since 3.5
9193     */
9194    public static String truncate(final String str, final int maxWidth) {
9195        return truncate(str, 0, maxWidth);
9196    }
9197
9198    /**
9199     * <p>Truncates a String. This will turn
9200     * "Now is the time for all good men" into "is the time for all".</p>
9201     *
9202     * <p>Works like {@code truncate(String, int)}, but allows you to specify
9203     * a "left edge" offset.
9204     *
9205     * <p>Specifically:</p>
9206     * <ul>
9207     *   <li>If {@code str} is less than {@code maxWidth} characters
9208     *       long, return it.</li>
9209     *   <li>Else truncate it to {@code substring(str, offset, maxWidth)}.</li>
9210     *   <li>If {@code maxWidth} is less than {@code 0}, throw an
9211     *       {@code IllegalArgumentException}.</li>
9212     *   <li>If {@code offset} is less than {@code 0}, throw an
9213     *       {@code IllegalArgumentException}.</li>
9214     *   <li>In no case will it return a String of length greater than
9215     *       {@code maxWidth}.</li>
9216     * </ul>
9217     *
9218     * <pre>
9219     * StringUtils.truncate(null, 0, 0) = null
9220     * StringUtils.truncate(null, 2, 4) = null
9221     * StringUtils.truncate("", 0, 10) = ""
9222     * StringUtils.truncate("", 2, 10) = ""
9223     * StringUtils.truncate("abcdefghij", 0, 3) = "abc"
9224     * StringUtils.truncate("abcdefghij", 5, 6) = "fghij"
9225     * StringUtils.truncate("raspberry peach", 10, 15) = "peach"
9226     * StringUtils.truncate("abcdefghijklmno", 0, 10) = "abcdefghij"
9227     * StringUtils.truncate("abcdefghijklmno", -1, 10) = throws an IllegalArgumentException
9228     * StringUtils.truncate("abcdefghijklmno", Integer.MIN_VALUE, 10) = throws an IllegalArgumentException
9229     * StringUtils.truncate("abcdefghijklmno", Integer.MIN_VALUE, Integer.MAX_VALUE) = throws an IllegalArgumentException
9230     * StringUtils.truncate("abcdefghijklmno", 0, Integer.MAX_VALUE) = "abcdefghijklmno"
9231     * StringUtils.truncate("abcdefghijklmno", 1, 10) = "bcdefghijk"
9232     * StringUtils.truncate("abcdefghijklmno", 2, 10) = "cdefghijkl"
9233     * StringUtils.truncate("abcdefghijklmno", 3, 10) = "defghijklm"
9234     * StringUtils.truncate("abcdefghijklmno", 4, 10) = "efghijklmn"
9235     * StringUtils.truncate("abcdefghijklmno", 5, 10) = "fghijklmno"
9236     * StringUtils.truncate("abcdefghijklmno", 5, 5) = "fghij"
9237     * StringUtils.truncate("abcdefghijklmno", 5, 3) = "fgh"
9238     * StringUtils.truncate("abcdefghijklmno", 10, 3) = "klm"
9239     * StringUtils.truncate("abcdefghijklmno", 10, Integer.MAX_VALUE) = "klmno"
9240     * StringUtils.truncate("abcdefghijklmno", 13, 1) = "n"
9241     * StringUtils.truncate("abcdefghijklmno", 13, Integer.MAX_VALUE) = "no"
9242     * StringUtils.truncate("abcdefghijklmno", 14, 1) = "o"
9243     * StringUtils.truncate("abcdefghijklmno", 14, Integer.MAX_VALUE) = "o"
9244     * StringUtils.truncate("abcdefghijklmno", 15, 1) = ""
9245     * StringUtils.truncate("abcdefghijklmno", 15, Integer.MAX_VALUE) = ""
9246     * StringUtils.truncate("abcdefghijklmno", Integer.MAX_VALUE, Integer.MAX_VALUE) = ""
9247     * StringUtils.truncate("abcdefghij", 3, -1) = throws an IllegalArgumentException
9248     * StringUtils.truncate("abcdefghij", -2, 4) = throws an IllegalArgumentException
9249     * </pre>
9250     *
9251     * @param str  the String to truncate, may be null
9252     * @param offset  left edge of source String
9253     * @param maxWidth  maximum length of result String, must be positive
9254     * @return truncated String, {@code null} if null String input
9255     * @throws IllegalArgumentException If {@code offset} or {@code maxWidth} is less than {@code 0}
9256     * @since 3.5
9257     */
9258    public static String truncate(final String str, final int offset, final int maxWidth) {
9259        if (offset < 0) {
9260            throw new IllegalArgumentException("offset cannot be negative");
9261        }
9262        if (maxWidth < 0) {
9263            throw new IllegalArgumentException("maxWith cannot be negative");
9264        }
9265        if (str == null) {
9266            return null;
9267        }
9268        if (offset > str.length()) {
9269            return EMPTY;
9270        }
9271        if (str.length() > maxWidth) {
9272            final int ix = Math.min(offset + maxWidth, str.length());
9273            return str.substring(offset, ix);
9274        }
9275        return str.substring(offset);
9276    }
9277
9278    /**
9279     * <p>Uncapitalizes a String, changing the first character to lower case as
9280     * per {@link Character#toLowerCase(int)}. No other characters are changed.</p>
9281     *
9282     * <p>For a word based algorithm, see {@link org.apache.commons.lang3.text.WordUtils#uncapitalize(String)}.
9283     * A {@code null} input String returns {@code null}.</p>
9284     *
9285     * <pre>
9286     * StringUtils.uncapitalize(null)  = null
9287     * StringUtils.uncapitalize("")    = ""
9288     * StringUtils.uncapitalize("cat") = "cat"
9289     * StringUtils.uncapitalize("Cat") = "cat"
9290     * StringUtils.uncapitalize("CAT") = "cAT"
9291     * </pre>
9292     *
9293     * @param str the String to uncapitalize, may be null
9294     * @return the uncapitalized String, {@code null} if null String input
9295     * @see org.apache.commons.lang3.text.WordUtils#uncapitalize(String)
9296     * @see #capitalize(String)
9297     * @since 2.0
9298     */
9299    public static String uncapitalize(final String str) {
9300        final int strLen = length(str);
9301        if (strLen == 0) {
9302            return str;
9303        }
9304
9305        final int firstCodepoint = str.codePointAt(0);
9306        final int newCodePoint = Character.toLowerCase(firstCodepoint);
9307        if (firstCodepoint == newCodePoint) {
9308            // already capitalized
9309            return str;
9310        }
9311
9312        final int[] newCodePoints = new int[strLen]; // cannot be longer than the char array
9313        int outOffset = 0;
9314        newCodePoints[outOffset++] = newCodePoint; // copy the first codepoint
9315        for (int inOffset = Character.charCount(firstCodepoint); inOffset < strLen; ) {
9316            final int codepoint = str.codePointAt(inOffset);
9317            newCodePoints[outOffset++] = codepoint; // copy the remaining ones
9318            inOffset += Character.charCount(codepoint);
9319         }
9320        return new String(newCodePoints, 0, outOffset);
9321    }
9322
9323    /**
9324     * <p>
9325     * Unwraps a given string from a character.
9326     * </p>
9327     *
9328     * <pre>
9329     * StringUtils.unwrap(null, null)         = null
9330     * StringUtils.unwrap(null, '\0')         = null
9331     * StringUtils.unwrap(null, '1')          = null
9332     * StringUtils.unwrap("a", 'a')           = "a"
9333     * StringUtils.unwrap("aa", 'a')           = ""
9334     * StringUtils.unwrap("\'abc\'", '\'')    = "abc"
9335     * StringUtils.unwrap("AABabcBAA", 'A')   = "ABabcBA"
9336     * StringUtils.unwrap("A", '#')           = "A"
9337     * StringUtils.unwrap("#A", '#')          = "#A"
9338     * StringUtils.unwrap("A#", '#')          = "A#"
9339     * </pre>
9340     *
9341     * @param str
9342     *          the String to be unwrapped, can be null
9343     * @param wrapChar
9344     *          the character used to unwrap
9345     * @return unwrapped String or the original string
9346     *          if it is not quoted properly with the wrapChar
9347     * @since 3.6
9348     */
9349    public static String unwrap(final String str, final char wrapChar) {
9350        if (isEmpty(str) || wrapChar == CharUtils.NUL || str.length() == 1) {
9351            return str;
9352        }
9353
9354        if (str.charAt(0) == wrapChar && str.charAt(str.length() - 1) == wrapChar) {
9355            final int startIndex = 0;
9356            final int endIndex = str.length() - 1;
9357
9358            return str.substring(startIndex + 1, endIndex);
9359        }
9360
9361        return str;
9362    }
9363
9364    /**
9365     * <p>
9366     * Unwraps a given string from anther string.
9367     * </p>
9368     *
9369     * <pre>
9370     * StringUtils.unwrap(null, null)         = null
9371     * StringUtils.unwrap(null, "")           = null
9372     * StringUtils.unwrap(null, "1")          = null
9373     * StringUtils.unwrap("a", "a")           = "a"
9374     * StringUtils.unwrap("aa", "a")          = ""
9375     * StringUtils.unwrap("\'abc\'", "\'")    = "abc"
9376     * StringUtils.unwrap("\"abc\"", "\"")    = "abc"
9377     * StringUtils.unwrap("AABabcBAA", "AA")  = "BabcB"
9378     * StringUtils.unwrap("A", "#")           = "A"
9379     * StringUtils.unwrap("#A", "#")          = "#A"
9380     * StringUtils.unwrap("A#", "#")          = "A#"
9381     * </pre>
9382     *
9383     * @param str
9384     *          the String to be unwrapped, can be null
9385     * @param wrapToken
9386     *          the String used to unwrap
9387     * @return unwrapped String or the original string
9388     *          if it is not quoted properly with the wrapToken
9389     * @since 3.6
9390     */
9391    public static String unwrap(final String str, final String wrapToken) {
9392        if (isEmpty(str) || isEmpty(wrapToken) || str.length() < 2 * wrapToken.length()) {
9393            return str;
9394        }
9395
9396        if (startsWith(str, wrapToken) && endsWith(str, wrapToken)) {
9397            final int startIndex = str.indexOf(wrapToken);
9398            final int endIndex = str.lastIndexOf(wrapToken);
9399            final int wrapLength = wrapToken.length();
9400
9401            if (startIndex != -1 && endIndex != -1) {
9402                return str.substring(startIndex + wrapLength, endIndex);
9403            }
9404        }
9405
9406        return str;
9407    }
9408
9409    /**
9410     * <p>Converts a String to upper case as per {@link String#toUpperCase()}.</p>
9411     *
9412     * <p>A {@code null} input String returns {@code null}.</p>
9413     *
9414     * <pre>
9415     * StringUtils.upperCase(null)  = null
9416     * StringUtils.upperCase("")    = ""
9417     * StringUtils.upperCase("aBc") = "ABC"
9418     * </pre>
9419     *
9420     * <p><strong>Note:</strong> As described in the documentation for {@link String#toUpperCase()},
9421     * the result of this method is affected by the current locale.
9422     * For platform-independent case transformations, the method {@link #lowerCase(String, Locale)}
9423     * should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
9424     *
9425     * @param str  the String to upper case, may be null
9426     * @return the upper cased String, {@code null} if null String input
9427     */
9428    public static String upperCase(final String str) {
9429        if (str == null) {
9430            return null;
9431        }
9432        return str.toUpperCase();
9433    }
9434
9435    /**
9436     * <p>Converts a String to upper case as per {@link String#toUpperCase(Locale)}.</p>
9437     *
9438     * <p>A {@code null} input String returns {@code null}.</p>
9439     *
9440     * <pre>
9441     * StringUtils.upperCase(null, Locale.ENGLISH)  = null
9442     * StringUtils.upperCase("", Locale.ENGLISH)    = ""
9443     * StringUtils.upperCase("aBc", Locale.ENGLISH) = "ABC"
9444     * </pre>
9445     *
9446     * @param str  the String to upper case, may be null
9447     * @param locale  the locale that defines the case transformation rules, must not be null
9448     * @return the upper cased String, {@code null} if null String input
9449     * @since 2.5
9450     */
9451    public static String upperCase(final String str, final Locale locale) {
9452        if (str == null) {
9453            return null;
9454        }
9455        return str.toUpperCase(LocaleUtils.toLocale(locale));
9456    }
9457
9458    /**
9459     * Returns the string representation of the {@code char} array or null.
9460     *
9461     * @param value the character array.
9462     * @return a String or null
9463     * @see String#valueOf(char[])
9464     * @since 3.9
9465     */
9466    public static String valueOf(final char[] value) {
9467        return value == null ? null : String.valueOf(value);
9468    }
9469
9470    /**
9471     * <p>
9472     * Wraps a string with a char.
9473     * </p>
9474     *
9475     * <pre>
9476     * StringUtils.wrap(null, *)        = null
9477     * StringUtils.wrap("", *)          = ""
9478     * StringUtils.wrap("ab", '\0')     = "ab"
9479     * StringUtils.wrap("ab", 'x')      = "xabx"
9480     * StringUtils.wrap("ab", '\'')     = "'ab'"
9481     * StringUtils.wrap("\"ab\"", '\"') = "\"\"ab\"\""
9482     * </pre>
9483     *
9484     * @param str
9485     *            the string to be wrapped, may be {@code null}
9486     * @param wrapWith
9487     *            the char that will wrap {@code str}
9488     * @return the wrapped string, or {@code null} if {@code str==null}
9489     * @since 3.4
9490     */
9491    public static String wrap(final String str, final char wrapWith) {
9492
9493        if (isEmpty(str) || wrapWith == CharUtils.NUL) {
9494            return str;
9495        }
9496
9497        return wrapWith + str + wrapWith;
9498    }
9499
9500    /**
9501     * <p>
9502     * Wraps a String with another String.
9503     * </p>
9504     *
9505     * <p>
9506     * A {@code null} input String returns {@code null}.
9507     * </p>
9508     *
9509     * <pre>
9510     * StringUtils.wrap(null, *)         = null
9511     * StringUtils.wrap("", *)           = ""
9512     * StringUtils.wrap("ab", null)      = "ab"
9513     * StringUtils.wrap("ab", "x")       = "xabx"
9514     * StringUtils.wrap("ab", "\"")      = "\"ab\""
9515     * StringUtils.wrap("\"ab\"", "\"")  = "\"\"ab\"\""
9516     * StringUtils.wrap("ab", "'")       = "'ab'"
9517     * StringUtils.wrap("'abcd'", "'")   = "''abcd''"
9518     * StringUtils.wrap("\"abcd\"", "'") = "'\"abcd\"'"
9519     * StringUtils.wrap("'abcd'", "\"")  = "\"'abcd'\""
9520     * </pre>
9521     *
9522     * @param str
9523     *            the String to be wrapper, may be null
9524     * @param wrapWith
9525     *            the String that will wrap str
9526     * @return wrapped String, {@code null} if null String input
9527     * @since 3.4
9528     */
9529    public static String wrap(final String str, final String wrapWith) {
9530
9531        if (isEmpty(str) || isEmpty(wrapWith)) {
9532            return str;
9533        }
9534
9535        return wrapWith.concat(str).concat(wrapWith);
9536    }
9537
9538    /**
9539     * <p>
9540     * Wraps a string with a char if that char is missing from the start or end of the given string.
9541     * </p>
9542     *
9543     * <p>A new {@code String} will not be created if {@code str} is already wrapped.</p>
9544     *
9545     * <pre>
9546     * StringUtils.wrapIfMissing(null, *)        = null
9547     * StringUtils.wrapIfMissing("", *)          = ""
9548     * StringUtils.wrapIfMissing("ab", '\0')     = "ab"
9549     * StringUtils.wrapIfMissing("ab", 'x')      = "xabx"
9550     * StringUtils.wrapIfMissing("ab", '\'')     = "'ab'"
9551     * StringUtils.wrapIfMissing("\"ab\"", '\"') = "\"ab\""
9552     * StringUtils.wrapIfMissing("/", '/')  = "/"
9553     * StringUtils.wrapIfMissing("a/b/c", '/')  = "/a/b/c/"
9554     * StringUtils.wrapIfMissing("/a/b/c", '/')  = "/a/b/c/"
9555     * StringUtils.wrapIfMissing("a/b/c/", '/')  = "/a/b/c/"
9556     * </pre>
9557     *
9558     * @param str
9559     *            the string to be wrapped, may be {@code null}
9560     * @param wrapWith
9561     *            the char that will wrap {@code str}
9562     * @return the wrapped string, or {@code null} if {@code str==null}
9563     * @since 3.5
9564     */
9565    public static String wrapIfMissing(final String str, final char wrapWith) {
9566        if (isEmpty(str) || wrapWith == CharUtils.NUL) {
9567            return str;
9568        }
9569        final boolean wrapStart = str.charAt(0) != wrapWith;
9570        final boolean wrapEnd = str.charAt(str.length() - 1) != wrapWith;
9571        if (!wrapStart && !wrapEnd) {
9572            return str;
9573        }
9574
9575        final StringBuilder builder = new StringBuilder(str.length() + 2);
9576        if (wrapStart) {
9577            builder.append(wrapWith);
9578        }
9579        builder.append(str);
9580        if (wrapEnd) {
9581            builder.append(wrapWith);
9582        }
9583        return builder.toString();
9584    }
9585
9586    /**
9587     * <p>
9588     * Wraps a string with a string if that string is missing from the start or end of the given string.
9589     * </p>
9590     *
9591     * <p>A new {@code String} will not be created if {@code str} is already wrapped.</p>
9592     *
9593     * <pre>
9594     * StringUtils.wrapIfMissing(null, *)         = null
9595     * StringUtils.wrapIfMissing("", *)           = ""
9596     * StringUtils.wrapIfMissing("ab", null)      = "ab"
9597     * StringUtils.wrapIfMissing("ab", "x")       = "xabx"
9598     * StringUtils.wrapIfMissing("ab", "\"")      = "\"ab\""
9599     * StringUtils.wrapIfMissing("\"ab\"", "\"")  = "\"ab\""
9600     * StringUtils.wrapIfMissing("ab", "'")       = "'ab'"
9601     * StringUtils.wrapIfMissing("'abcd'", "'")   = "'abcd'"
9602     * StringUtils.wrapIfMissing("\"abcd\"", "'") = "'\"abcd\"'"
9603     * StringUtils.wrapIfMissing("'abcd'", "\"")  = "\"'abcd'\""
9604     * StringUtils.wrapIfMissing("/", "/")  = "/"
9605     * StringUtils.wrapIfMissing("a/b/c", "/")  = "/a/b/c/"
9606     * StringUtils.wrapIfMissing("/a/b/c", "/")  = "/a/b/c/"
9607     * StringUtils.wrapIfMissing("a/b/c/", "/")  = "/a/b/c/"
9608     * </pre>
9609     *
9610     * @param str
9611     *            the string to be wrapped, may be {@code null}
9612     * @param wrapWith
9613     *            the string that will wrap {@code str}
9614     * @return the wrapped string, or {@code null} if {@code str==null}
9615     * @since 3.5
9616     */
9617    public static String wrapIfMissing(final String str, final String wrapWith) {
9618        if (isEmpty(str) || isEmpty(wrapWith)) {
9619            return str;
9620        }
9621
9622        final boolean wrapStart = !str.startsWith(wrapWith);
9623        final boolean wrapEnd = !str.endsWith(wrapWith);
9624        if (!wrapStart && !wrapEnd) {
9625            return str;
9626        }
9627
9628        final StringBuilder builder = new StringBuilder(str.length() + wrapWith.length() + wrapWith.length());
9629        if (wrapStart) {
9630            builder.append(wrapWith);
9631        }
9632        builder.append(str);
9633        if (wrapEnd) {
9634            builder.append(wrapWith);
9635        }
9636        return builder.toString();
9637    }
9638
9639    /**
9640     * <p>{@code StringUtils} instances should NOT be constructed in
9641     * standard programming. Instead, the class should be used as
9642     * {@code StringUtils.trim(" foo ");}.</p>
9643     *
9644     * <p>This constructor is public to permit tools that require a JavaBean
9645     * instance to operate.</p>
9646     */
9647    public StringUtils() {
9648    }
9649
9650}