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 *      https://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.CharBuffer;
021import java.nio.charset.Charset;
022import java.text.Normalizer;
023import java.util.ArrayList;
024import java.util.Arrays;
025import java.util.Iterator;
026import java.util.List;
027import java.util.Locale;
028import java.util.Objects;
029import java.util.Set;
030import java.util.function.Supplier;
031import java.util.regex.Pattern;
032import java.util.stream.Collectors;
033
034import org.apache.commons.lang3.function.Suppliers;
035import org.apache.commons.lang3.stream.LangCollectors;
036import org.apache.commons.lang3.stream.Streams;
037
038/**
039 * Operations on {@link String} that are
040 * {@code null} safe.
041 *
042 * <ul>
043 *  <li><strong>IsEmpty/IsBlank</strong>
044 *      - checks if a String contains text</li>
045 *  <li><strong>Trim/Strip</strong>
046 *      - removes leading and trailing whitespace</li>
047 *  <li><strong>Equals/Compare</strong>
048 *      - compares two strings in a null-safe manner</li>
049 *  <li><strong>startsWith</strong>
050 *      - check if a String starts with a prefix in a null-safe manner</li>
051 *  <li><strong>endsWith</strong>
052 *      - check if a String ends with a suffix in a null-safe manner</li>
053 *  <li><strong>IndexOf/LastIndexOf/Contains</strong>
054 *      - null-safe index-of checks
055 *  <li><strong>IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut</strong>
056 *      - index-of any of a set of Strings</li>
057 *  <li><strong>ContainsOnly/ContainsNone/ContainsAny</strong>
058 *      - checks if String contains only/none/any of these characters</li>
059 *  <li><strong>Substring/Left/Right/Mid</strong>
060 *      - null-safe substring extractions</li>
061 *  <li><strong>SubstringBefore/SubstringAfter/SubstringBetween</strong>
062 *      - substring extraction relative to other strings</li>
063 *  <li><strong>Split/Join</strong>
064 *      - splits a String into an array of substrings and vice versa</li>
065 *  <li><strong>Remove/Delete</strong>
066 *      - removes part of a String</li>
067 *  <li><strong>Replace/Overlay</strong>
068 *      - Searches a String and replaces one String with another</li>
069 *  <li><strong>Chomp/Chop</strong>
070 *      - removes the last part of a String</li>
071 *  <li><strong>AppendIfMissing</strong>
072 *      - appends a suffix to the end of the String if not present</li>
073 *  <li><strong>PrependIfMissing</strong>
074 *      - prepends a prefix to the start of the String if not present</li>
075 *  <li><strong>LeftPad/RightPad/Center/Repeat</strong>
076 *      - pads a String</li>
077 *  <li><strong>UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize</strong>
078 *      - changes the case of a String</li>
079 *  <li><strong>CountMatches</strong>
080 *      - counts the number of occurrences of one String in another</li>
081 *  <li><strong>IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable</strong>
082 *      - checks the characters in a String</li>
083 *  <li><strong>DefaultString</strong>
084 *      - protects against a null input String</li>
085 *  <li><strong>Rotate</strong>
086 *      - rotate (circular shift) a String</li>
087 *  <li><strong>Reverse/ReverseDelimited</strong>
088 *      - reverses a String</li>
089 *  <li><strong>Abbreviate</strong>
090 *      - abbreviates a string using ellipses or another given String</li>
091 *  <li><strong>Difference</strong>
092 *      - compares Strings and reports on their differences</li>
093 *  <li><strong>LevenshteinDistance</strong>
094 *      - the number of changes needed to change one String into another</li>
095 * </ul>
096 *
097 * <p>The {@link StringUtils} class defines certain words related to
098 * String handling.</p>
099 *
100 * <ul>
101 *  <li>null - {@code null}</li>
102 *  <li>empty - a zero-length string ({@code ""})</li>
103 *  <li>space - the space character ({@code ' '}, char 32)</li>
104 *  <li>whitespace - the characters defined by {@link Character#isWhitespace(char)}</li>
105 *  <li>trim - the characters &lt;= 32 as in {@link String#trim()}</li>
106 * </ul>
107 *
108 * <p>{@link StringUtils} handles {@code null} input Strings quietly.
109 * That is to say that a {@code null} input will return {@code null}.
110 * Where a {@code boolean} or {@code int} is being returned
111 * details vary by method.</p>
112 *
113 * <p>A side effect of the {@code null} handling is that a
114 * {@link NullPointerException} should be considered a bug in
115 * {@link StringUtils}.</p>
116 *
117 * <p>Methods in this class include sample code in their Javadoc comments to explain their operation.
118 * The symbol {@code *} is used to indicate any input including {@code null}.</p>
119 *
120 * <p>#ThreadSafe#</p>
121 * @see String
122 * @since 1.0
123 */
124//@Immutable
125public class StringUtils {
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     * This is a 3 character version of an ellipsis. There is a Unicode character for a HORIZONTAL ELLIPSIS, U+2026 … this isn't it.
145     */
146    private static final String ELLIPSIS3 = "...";
147
148    /**
149     * A String for a space character.
150     *
151     * @since 3.2
152     */
153    public static final String SPACE = " ";
154
155    /**
156     * The empty String {@code ""}.
157     * @since 2.0
158     */
159    public static final String EMPTY = "";
160
161    /**
162     * The null String {@code null}. Package-private only.
163     */
164    static final String NULL = null;
165
166    /**
167     * A String for linefeed LF ("\n").
168     *
169     * @see <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences
170     *      for Character and String Literals</a>
171     * @since 3.2
172     */
173    public static final String LF = "\n";
174
175    /**
176     * A String for carriage return CR ("\r").
177     *
178     * @see <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences
179     *      for Character and String Literals</a>
180     * @since 3.2
181     */
182    public static final String CR = "\r";
183
184    /**
185     * Represents a failed index search.
186     * @since 2.1
187     */
188    public static final int INDEX_NOT_FOUND = -1;
189
190    /**
191     * The maximum size to which the padding constant(s) can expand.
192     */
193    private static final int PAD_LIMIT = 8192;
194
195    /**
196     * The default maximum depth at which recursive replacement will continue until no further search replacements are possible.
197     */
198    private static final int DEFAULT_TTL = 5;
199
200    /**
201     * Pattern used in {@link #stripAccents(String)}.
202     */
203    private static final Pattern STRIP_ACCENTS_PATTERN = Pattern.compile("\\p{InCombiningDiacriticalMarks}+"); //$NON-NLS-1$
204
205    /**
206     * Abbreviates a String using ellipses. This will turn
207     * "Now is the time for all good men" into "Now is the time for..."
208     *
209     * <p>Specifically:</p>
210     * <ul>
211     *   <li>If the number of characters in {@code str} is less than or equal to
212     *       {@code maxWidth}, return {@code str}.</li>
213     *   <li>Else abbreviate it to {@code (substring(str, 0, max-3) + "...")}.</li>
214     *   <li>If {@code maxWidth} is less than {@code 4}, throw an
215     *       {@link IllegalArgumentException}.</li>
216     *   <li>In no case will it return a String of length greater than
217     *       {@code maxWidth}.</li>
218     * </ul>
219     *
220     * <pre>
221     * StringUtils.abbreviate(null, *)      = null
222     * StringUtils.abbreviate("", 4)        = ""
223     * StringUtils.abbreviate("abcdefg", 6) = "abc..."
224     * StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
225     * StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
226     * StringUtils.abbreviate("abcdefg", 4) = "a..."
227     * StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
228     * </pre>
229     *
230     * @param str  the String to check, may be null
231     * @param maxWidth  maximum length of result String, must be at least 4
232     * @return abbreviated String, {@code null} if null String input
233     * @throws IllegalArgumentException if the width is too small
234     * @since 2.0
235     */
236    public static String abbreviate(final String str, final int maxWidth) {
237        return abbreviate(str, ELLIPSIS3, 0, maxWidth);
238    }
239
240    /**
241     * Abbreviates a String using ellipses. This will turn
242     * "Now is the time for all good men" into "...is the time for..."
243     *
244     * <p>Works like {@code abbreviate(String, int)}, but allows you to specify
245     * a "left edge" offset.  Note that this left edge is not necessarily going to
246     * be the leftmost character in the result, or the first character following the
247     * ellipses, but it will appear somewhere in the result.
248     *
249     * <p>In no case will it return a String of length greater than
250     * {@code maxWidth}.</p>
251     *
252     * <pre>
253     * StringUtils.abbreviate(null, *, *)                = null
254     * StringUtils.abbreviate("", 0, 4)                  = ""
255     * StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
256     * StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
257     * StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
258     * StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
259     * StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
260     * StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
261     * StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
262     * StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
263     * StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
264     * StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
265     * StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
266     * </pre>
267     *
268     * @param str  the String to check, may be null
269     * @param offset  left edge of source String
270     * @param maxWidth  maximum length of result String, must be at least 4
271     * @return abbreviated String, {@code null} if null String input
272     * @throws IllegalArgumentException if the width is too small
273     * @since 2.0
274     */
275    public static String abbreviate(final String str, final int offset, final int maxWidth) {
276        return abbreviate(str, ELLIPSIS3, offset, maxWidth);
277    }
278
279    /**
280     * Abbreviates a String using another given String as replacement marker. This will turn
281     * "Now is the time for all good men" into "Now is the time for..." if "..." was defined
282     * as the replacement marker.
283     *
284     * <p>Specifically:</p>
285     * <ul>
286     *   <li>If the number of characters in {@code str} is less than or equal to
287     *       {@code maxWidth}, return {@code str}.</li>
288     *   <li>Else abbreviate it to {@code (substring(str, 0, max-abbrevMarker.length) + abbrevMarker)}.</li>
289     *   <li>If {@code maxWidth} is less than {@code abbrevMarker.length + 1}, throw an
290     *       {@link IllegalArgumentException}.</li>
291     *   <li>In no case will it return a String of length greater than
292     *       {@code maxWidth}.</li>
293     * </ul>
294     *
295     * <pre>
296     * StringUtils.abbreviate(null, "...", *)      = null
297     * StringUtils.abbreviate("abcdefg", null, *)  = "abcdefg"
298     * StringUtils.abbreviate("", "...", 4)        = ""
299     * StringUtils.abbreviate("abcdefg", ".", 5)   = "abcd."
300     * StringUtils.abbreviate("abcdefg", ".", 7)   = "abcdefg"
301     * StringUtils.abbreviate("abcdefg", ".", 8)   = "abcdefg"
302     * StringUtils.abbreviate("abcdefg", "..", 4)  = "ab.."
303     * StringUtils.abbreviate("abcdefg", "..", 3)  = "a.."
304     * StringUtils.abbreviate("abcdefg", "..", 2)  = IllegalArgumentException
305     * StringUtils.abbreviate("abcdefg", "...", 3) = IllegalArgumentException
306     * </pre>
307     *
308     * @param str  the String to check, may be null
309     * @param abbrevMarker  the String used as replacement marker
310     * @param maxWidth  maximum length of result String, must be at least {@code abbrevMarker.length + 1}
311     * @return abbreviated String, {@code null} if null String input
312     * @throws IllegalArgumentException if the width is too small
313     * @since 3.6
314     */
315    public static String abbreviate(final String str, final String abbrevMarker, final int maxWidth) {
316        return abbreviate(str, abbrevMarker, 0, maxWidth);
317    }
318    /**
319     * Abbreviates a String using a given replacement marker. This will turn
320     * "Now is the time for all good men" into "...is the time for..." if "..." was defined
321     * as the replacement marker.
322     *
323     * <p>Works like {@code abbreviate(String, String, int)}, but allows you to specify
324     * a "left edge" offset.  Note that this left edge is not necessarily going to
325     * be the leftmost character in the result, or the first character following the
326     * replacement marker, but it will appear somewhere in the result.
327     *
328     * <p>In no case will it return a String of length greater than {@code maxWidth}.</p>
329     *
330     * <pre>
331     * StringUtils.abbreviate(null, null, *, *)                 = null
332     * StringUtils.abbreviate("abcdefghijklmno", null, *, *)    = "abcdefghijklmno"
333     * StringUtils.abbreviate("", "...", 0, 4)                  = ""
334     * StringUtils.abbreviate("abcdefghijklmno", "---", -1, 10) = "abcdefg---"
335     * StringUtils.abbreviate("abcdefghijklmno", ",", 0, 10)    = "abcdefghi,"
336     * StringUtils.abbreviate("abcdefghijklmno", ",", 1, 10)    = "abcdefghi,"
337     * StringUtils.abbreviate("abcdefghijklmno", ",", 2, 10)    = "abcdefghi,"
338     * StringUtils.abbreviate("abcdefghijklmno", "::", 4, 10)   = "::efghij::"
339     * StringUtils.abbreviate("abcdefghijklmno", "...", 6, 10)  = "...ghij..."
340     * StringUtils.abbreviate("abcdefghijklmno", "*", 9, 10)    = "*ghijklmno"
341     * StringUtils.abbreviate("abcdefghijklmno", "'", 10, 10)   = "'ghijklmno"
342     * StringUtils.abbreviate("abcdefghijklmno", "!", 12, 10)   = "!ghijklmno"
343     * StringUtils.abbreviate("abcdefghij", "abra", 0, 4)       = IllegalArgumentException
344     * StringUtils.abbreviate("abcdefghij", "...", 5, 6)        = IllegalArgumentException
345     * </pre>
346     *
347     * @param str  the String to check, may be null
348     * @param abbrevMarker  the String used as replacement marker
349     * @param offset  left edge of source String
350     * @param maxWidth  maximum length of result String, must be at least 4
351     * @return abbreviated String, {@code null} if null String input
352     * @throws IllegalArgumentException if the width is too small
353     * @since 3.6
354     */
355    public static String abbreviate(final String str, final String abbrevMarker, int offset, final int maxWidth) {
356        if (isNotEmpty(str) && EMPTY.equals(abbrevMarker) && maxWidth > 0) {
357            return substring(str, 0, maxWidth);
358        }
359        if (isAnyEmpty(str, abbrevMarker)) {
360            return str;
361        }
362        final int abbrevMarkerLength = abbrevMarker.length();
363        final int minAbbrevWidth = abbrevMarkerLength + 1;
364        final int minAbbrevWidthOffset = abbrevMarkerLength + abbrevMarkerLength + 1;
365
366        if (maxWidth < minAbbrevWidth) {
367            throw new IllegalArgumentException(String.format("Minimum abbreviation width is %d", minAbbrevWidth));
368        }
369        final int strLen = str.length();
370        if (strLen <= maxWidth) {
371            return str;
372        }
373        if (offset > strLen) {
374            offset = strLen;
375        }
376        if (strLen - offset < maxWidth - abbrevMarkerLength) {
377            offset = strLen - (maxWidth - abbrevMarkerLength);
378        }
379        if (offset <= abbrevMarkerLength + 1) {
380            return str.substring(0, maxWidth - abbrevMarkerLength) + abbrevMarker;
381        }
382        if (maxWidth < minAbbrevWidthOffset) {
383            throw new IllegalArgumentException(String.format("Minimum abbreviation width with offset is %d", minAbbrevWidthOffset));
384        }
385        if (offset + maxWidth - abbrevMarkerLength < strLen) {
386            return abbrevMarker + abbreviate(str.substring(offset), abbrevMarker, maxWidth - abbrevMarkerLength);
387        }
388        return abbrevMarker + str.substring(strLen - (maxWidth - abbrevMarkerLength));
389    }
390
391    /**
392     * Abbreviates a String to the length passed, replacing the middle characters with the supplied
393     * replacement String.
394     *
395     * <p>This abbreviation only occurs if the following criteria is met:</p>
396     * <ul>
397     * <li>Neither the String for abbreviation nor the replacement String are null or empty </li>
398     * <li>The length to truncate to is less than the length of the supplied String</li>
399     * <li>The length to truncate to is greater than 0</li>
400     * <li>The abbreviated String will have enough room for the length supplied replacement String
401     * and the first and last characters of the supplied String for abbreviation</li>
402     * </ul>
403     * <p>Otherwise, the returned String will be the same as the supplied String for abbreviation.
404     * </p>
405     *
406     * <pre>
407     * StringUtils.abbreviateMiddle(null, null, 0)    = null
408     * StringUtils.abbreviateMiddle("abc", null, 0)   = "abc"
409     * StringUtils.abbreviateMiddle("abc", ".", 0)    = "abc"
410     * StringUtils.abbreviateMiddle("abc", ".", 3)    = "abc"
411     * StringUtils.abbreviateMiddle("abcdef", ".", 4) = "ab.f"
412     * </pre>
413     *
414     * @param str  the String to abbreviate, may be null
415     * @param middle the String to replace the middle characters with, may be null
416     * @param length the length to abbreviate {@code str} to.
417     * @return the abbreviated String if the above criteria is met, or the original String supplied for abbreviation.
418     * @since 2.5
419     */
420    public static String abbreviateMiddle(final String str, final String middle, final int length) {
421        if (isAnyEmpty(str, middle) || length >= str.length() || length < middle.length() + 2) {
422            return str;
423        }
424        final int targetSting = length - middle.length();
425        final int startOffset = targetSting / 2 + targetSting % 2;
426        final int endOffset = str.length() - targetSting / 2;
427        return str.substring(0, startOffset) + middle + str.substring(endOffset);
428    }
429
430    /**
431     * Appends the suffix to the end of the string if the string does not already end with any of the suffixes.
432     *
433     * <pre>
434     * StringUtils.appendIfMissing(null, null)      = null
435     * StringUtils.appendIfMissing("abc", null)     = "abc"
436     * StringUtils.appendIfMissing("", "xyz"        = "xyz"
437     * StringUtils.appendIfMissing("abc", "xyz")    = "abcxyz"
438     * StringUtils.appendIfMissing("abcxyz", "xyz") = "abcxyz"
439     * StringUtils.appendIfMissing("abcXYZ", "xyz") = "abcXYZxyz"
440     * </pre>
441     * <p>
442     * With additional suffixes,
443     * </p>
444     *
445     * <pre>
446     * StringUtils.appendIfMissing(null, null, null)       = null
447     * StringUtils.appendIfMissing("abc", null, null)      = "abc"
448     * StringUtils.appendIfMissing("", "xyz", null)        = "xyz"
449     * StringUtils.appendIfMissing("abc", "xyz", new CharSequence[]{null}) = "abcxyz"
450     * StringUtils.appendIfMissing("abc", "xyz", "")       = "abc"
451     * StringUtils.appendIfMissing("abc", "xyz", "mno")    = "abcxyz"
452     * StringUtils.appendIfMissing("abcxyz", "xyz", "mno") = "abcxyz"
453     * StringUtils.appendIfMissing("abcmno", "xyz", "mno") = "abcmno"
454     * StringUtils.appendIfMissing("abcXYZ", "xyz", "mno") = "abcXYZxyz"
455     * StringUtils.appendIfMissing("abcMNO", "xyz", "mno") = "abcMNOxyz"
456     * </pre>
457     *
458     * @param str      The string.
459     * @param suffix   The suffix to append to the end of the string.
460     * @param suffixes Additional suffixes that are valid terminators.
461     * @return A new String if suffix was appended, the same string otherwise.
462     * @since 3.2
463     * @deprecated Use {@link Strings#appendIfMissing(String, CharSequence, CharSequence...) Strings.CS.appendIfMissing(String, CharSequence, CharSequence...)}
464     */
465    @Deprecated
466    public static String appendIfMissing(final String str, final CharSequence suffix, final CharSequence... suffixes) {
467        return Strings.CS.appendIfMissing(str, suffix, suffixes);
468    }
469
470    /**
471     * Appends the suffix to the end of the string if the string does not
472     * already end, case-insensitive, with any of the suffixes.
473     *
474     * <pre>
475     * StringUtils.appendIfMissingIgnoreCase(null, null)      = null
476     * StringUtils.appendIfMissingIgnoreCase("abc", null)     = "abc"
477     * StringUtils.appendIfMissingIgnoreCase("", "xyz")       = "xyz"
478     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz")    = "abcxyz"
479     * StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz") = "abcxyz"
480     * StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz") = "abcXYZ"
481     * </pre>
482     * <p>With additional suffixes,</p>
483     * <pre>
484     * StringUtils.appendIfMissingIgnoreCase(null, null, null)       = null
485     * StringUtils.appendIfMissingIgnoreCase("abc", null, null)      = "abc"
486     * StringUtils.appendIfMissingIgnoreCase("", "xyz", null)        = "xyz"
487     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", new CharSequence[]{null}) = "abcxyz"
488     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "")       = "abc"
489     * StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "mno")    = "abcxyz"
490     * StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz", "mno") = "abcxyz"
491     * StringUtils.appendIfMissingIgnoreCase("abcmno", "xyz", "mno") = "abcmno"
492     * StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz", "mno") = "abcXYZ"
493     * StringUtils.appendIfMissingIgnoreCase("abcMNO", "xyz", "mno") = "abcMNO"
494     * </pre>
495     *
496     * @param str The string.
497     * @param suffix The suffix to append to the end of the string.
498     * @param suffixes Additional suffixes that are valid terminators.
499     * @return A new String if suffix was appended, the same string otherwise.
500     * @since 3.2
501     * @deprecated Use {@link Strings#appendIfMissing(String, CharSequence, CharSequence...) Strings.CI.appendIfMissing(String, CharSequence, CharSequence...)}
502     */
503    @Deprecated
504    public static String appendIfMissingIgnoreCase(final String str, final CharSequence suffix, final CharSequence... suffixes) {
505        return Strings.CI.appendIfMissing(str, suffix, suffixes);
506    }
507
508    /**
509     * Capitalizes a String changing the first character to title case as
510     * per {@link Character#toTitleCase(int)}. No other characters are changed.
511     *
512     * <p>For a word based algorithm, see {@link org.apache.commons.text.WordUtils#capitalize(String)}.
513     * A {@code null} input String returns {@code null}.</p>
514     *
515     * <pre>
516     * StringUtils.capitalize(null)    = null
517     * StringUtils.capitalize("")      = ""
518     * StringUtils.capitalize("cat")   = "Cat"
519     * StringUtils.capitalize("cAt")   = "CAt"
520     * StringUtils.capitalize("'cat'") = "'cat'"
521     * </pre>
522     *
523     * @param str the String to capitalize, may be null
524     * @return the capitalized String, {@code null} if null String input
525     * @see org.apache.commons.text.WordUtils#capitalize(String)
526     * @see #uncapitalize(String)
527     * @since 2.0
528     */
529    public static String capitalize(final String str) {
530        if (isEmpty(str)) {
531            return str;
532        }
533        final int firstCodepoint = str.codePointAt(0);
534        final int newCodePoint = Character.toTitleCase(firstCodepoint);
535        if (firstCodepoint == newCodePoint) {
536            // already capitalized
537            return str;
538        }
539        final int[] newCodePoints = str.codePoints().toArray();
540        newCodePoints[0] = newCodePoint; // copy the first code point
541        return new String(newCodePoints, 0, newCodePoints.length);
542    }
543
544    /**
545     * Centers a String in a larger String of size {@code size}
546     * using the space character (' ').
547     *
548     * <p>If the size is less than the String length, the original String is returned.
549     * A {@code null} String returns {@code null}.
550     * A negative size is treated as zero.</p>
551     *
552     * <p>Equivalent to {@code center(str, size, " ")}.</p>
553     *
554     * <pre>
555     * StringUtils.center(null, *)   = null
556     * StringUtils.center("", 4)     = "    "
557     * StringUtils.center("ab", -1)  = "ab"
558     * StringUtils.center("ab", 4)   = " ab "
559     * StringUtils.center("abcd", 2) = "abcd"
560     * StringUtils.center("a", 4)    = " a  "
561     * </pre>
562     *
563     * @param str  the String to center, may be null
564     * @param size  the int size of new String, negative treated as zero
565     * @return centered String, {@code null} if null String input
566     */
567    public static String center(final String str, final int size) {
568        return center(str, size, ' ');
569    }
570
571    /**
572     * Centers a String in a larger String of size {@code size}.
573     * Uses a supplied character as the value to pad the String with.
574     *
575     * <p>If the size is less than the String length, the String is returned.
576     * A {@code null} String returns {@code null}.
577     * A negative size is treated as zero.</p>
578     *
579     * <pre>
580     * StringUtils.center(null, *, *)     = null
581     * StringUtils.center("", 4, ' ')     = "    "
582     * StringUtils.center("ab", -1, ' ')  = "ab"
583     * StringUtils.center("ab", 4, ' ')   = " ab "
584     * StringUtils.center("abcd", 2, ' ') = "abcd"
585     * StringUtils.center("a", 4, ' ')    = " a  "
586     * StringUtils.center("a", 4, 'y')    = "yayy"
587     * </pre>
588     *
589     * @param str  the String to center, may be null
590     * @param size  the int size of new String, negative treated as zero
591     * @param padChar  the character to pad the new String with
592     * @return centered String, {@code null} if null String input
593     * @since 2.0
594     */
595    public static String center(String str, final int size, final char padChar) {
596        if (str == null || size <= 0) {
597            return str;
598        }
599        final int strLen = str.length();
600        final int pads = size - strLen;
601        if (pads <= 0) {
602            return str;
603        }
604        str = leftPad(str, strLen + pads / 2, padChar);
605        return rightPad(str, size, padChar);
606    }
607
608    /**
609     * Centers a String in a larger String of size {@code size}.
610     * Uses a supplied String as the value to pad the String with.
611     *
612     * <p>If the size is less than the String length, the String is returned.
613     * A {@code null} String returns {@code null}.
614     * A negative size is treated as zero.</p>
615     *
616     * <pre>
617     * StringUtils.center(null, *, *)     = null
618     * StringUtils.center("", 4, " ")     = "    "
619     * StringUtils.center("ab", -1, " ")  = "ab"
620     * StringUtils.center("ab", 4, " ")   = " ab "
621     * StringUtils.center("abcd", 2, " ") = "abcd"
622     * StringUtils.center("a", 4, " ")    = " a  "
623     * StringUtils.center("a", 4, "yz")   = "yayz"
624     * StringUtils.center("abc", 7, null) = "  abc  "
625     * StringUtils.center("abc", 7, "")   = "  abc  "
626     * </pre>
627     *
628     * @param str  the String to center, may be null
629     * @param size  the int size of new String, negative treated as zero
630     * @param padStr  the String to pad the new String with, must not be null or empty
631     * @return centered String, {@code null} if null String input
632     * @throws IllegalArgumentException if padStr is {@code null} or empty
633     */
634    public static String center(String str, final int size, String padStr) {
635        if (str == null || size <= 0) {
636            return str;
637        }
638        if (isEmpty(padStr)) {
639            padStr = SPACE;
640        }
641        final int strLen = str.length();
642        final int pads = size - strLen;
643        if (pads <= 0) {
644            return str;
645        }
646        str = leftPad(str, strLen + pads / 2, padStr);
647        return rightPad(str, size, padStr);
648    }
649
650    /**
651     * Removes one newline from end of a String if it's there,
652     * otherwise leave it alone.  A newline is &quot;{@code \n}&quot;,
653     * &quot;{@code \r}&quot;, or &quot;{@code \r\n}&quot;.
654     *
655     * <p>NOTE: This method changed in 2.0.
656     * It now more closely matches Perl chomp.</p>
657     *
658     * <pre>
659     * StringUtils.chomp(null)          = null
660     * StringUtils.chomp("")            = ""
661     * StringUtils.chomp("abc \r")      = "abc "
662     * StringUtils.chomp("abc\n")       = "abc"
663     * StringUtils.chomp("abc\r\n")     = "abc"
664     * StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
665     * StringUtils.chomp("abc\n\r")     = "abc\n"
666     * StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
667     * StringUtils.chomp("\r")          = ""
668     * StringUtils.chomp("\n")          = ""
669     * StringUtils.chomp("\r\n")        = ""
670     * </pre>
671     *
672     * @param str  the String to chomp a newline from, may be null
673     * @return String without newline, {@code null} if null String input
674     */
675    public static String chomp(final String str) {
676        if (isEmpty(str)) {
677            return str;
678        }
679
680        if (str.length() == 1) {
681            final char ch = str.charAt(0);
682            if (ch == CharUtils.CR || ch == CharUtils.LF) {
683                return EMPTY;
684            }
685            return str;
686        }
687
688        int lastIdx = str.length() - 1;
689        final char last = str.charAt(lastIdx);
690
691        if (last == CharUtils.LF) {
692            if (str.charAt(lastIdx - 1) == CharUtils.CR) {
693                lastIdx--;
694            }
695        } else if (last != CharUtils.CR) {
696            lastIdx++;
697        }
698        return str.substring(0, lastIdx);
699    }
700
701    /**
702     * Removes {@code separator} from the end of
703     * {@code str} if it's there, otherwise leave it alone.
704     *
705     * <p>NOTE: This method changed in version 2.0.
706     * It now more closely matches Perl chomp.
707     * For the previous behavior, use {@link #substringBeforeLast(String, String)}.
708     * This method uses {@link String#endsWith(String)}.</p>
709     *
710     * <pre>
711     * StringUtils.chomp(null, *)         = null
712     * StringUtils.chomp("", *)           = ""
713     * StringUtils.chomp("foobar", "bar") = "foo"
714     * StringUtils.chomp("foobar", "baz") = "foobar"
715     * StringUtils.chomp("foo", "foo")    = ""
716     * StringUtils.chomp("foo ", "foo")   = "foo "
717     * StringUtils.chomp(" foo", "foo")   = " "
718     * StringUtils.chomp("foo", "foooo")  = "foo"
719     * StringUtils.chomp("foo", "")       = "foo"
720     * StringUtils.chomp("foo", null)     = "foo"
721     * </pre>
722     *
723     * @param str  the String to chomp from, may be null
724     * @param separator  separator String, may be null
725     * @return String without trailing separator, {@code null} if null String input
726     * @deprecated This feature will be removed in Lang 4, use {@link StringUtils#removeEnd(String, String)} instead
727     */
728    @Deprecated
729    public static String chomp(final String str, final String separator) {
730        return Strings.CS.removeEnd(str, separator);
731    }
732
733    /**
734     * Remove the last character from a String.
735     *
736     * <p>If the String ends in {@code \r\n}, then remove both
737     * of them.</p>
738     *
739     * <pre>
740     * StringUtils.chop(null)          = null
741     * StringUtils.chop("")            = ""
742     * StringUtils.chop("abc \r")      = "abc "
743     * StringUtils.chop("abc\n")       = "abc"
744     * StringUtils.chop("abc\r\n")     = "abc"
745     * StringUtils.chop("abc")         = "ab"
746     * StringUtils.chop("abc\nabc")    = "abc\nab"
747     * StringUtils.chop("a")           = ""
748     * StringUtils.chop("\r")          = ""
749     * StringUtils.chop("\n")          = ""
750     * StringUtils.chop("\r\n")        = ""
751     * </pre>
752     *
753     * @param str  the String to chop last character from, may be null
754     * @return String without last character, {@code null} if null String input
755     */
756    public static String chop(final String str) {
757        if (str == null) {
758            return null;
759        }
760        final int strLen = str.length();
761        if (strLen < 2) {
762            return EMPTY;
763        }
764        final int lastIdx = strLen - 1;
765        final String ret = str.substring(0, lastIdx);
766        final char last = str.charAt(lastIdx);
767        if (last == CharUtils.LF && ret.charAt(lastIdx - 1) == CharUtils.CR) {
768            return ret.substring(0, lastIdx - 1);
769        }
770        return ret;
771    }
772
773    /**
774     * Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :
775     * <ul>
776     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
777     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
778     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
779     * </ul>
780     *
781     * <p>This is a {@code null} safe version of :</p>
782     * <blockquote><pre>str1.compareTo(str2)</pre></blockquote>
783     *
784     * <p>{@code null} value is considered less than non-{@code null} value.
785     * Two {@code null} references are considered equal.</p>
786     *
787     * <pre>{@code
788     * StringUtils.compare(null, null)   = 0
789     * StringUtils.compare(null , "a")   < 0
790     * StringUtils.compare("a", null)   > 0
791     * StringUtils.compare("abc", "abc") = 0
792     * StringUtils.compare("a", "b")     < 0
793     * StringUtils.compare("b", "a")     > 0
794     * StringUtils.compare("a", "B")     > 0
795     * StringUtils.compare("ab", "abc")  < 0
796     * }</pre>
797     *
798     * @see #compare(String, String, boolean)
799     * @see String#compareTo(String)
800     * @param str1  the String to compare from
801     * @param str2  the String to compare to
802     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal or greater than {@code str2}
803     * @since 3.5
804     * @deprecated Use {@link Strings#compare(String, String) Strings.CS.compare(String, String)}
805     */
806    @Deprecated
807    public static int compare(final String str1, final String str2) {
808        return Strings.CS.compare(str1, str2);
809    }
810
811    /**
812     * Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :
813     * <ul>
814     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
815     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
816     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
817     * </ul>
818     *
819     * <p>This is a {@code null} safe version of :</p>
820     * <blockquote><pre>str1.compareTo(str2)</pre></blockquote>
821     *
822     * <p>{@code null} inputs are handled according to the {@code nullIsLess} parameter.
823     * Two {@code null} references are considered equal.</p>
824     *
825     * <pre>{@code
826     * StringUtils.compare(null, null, *)     = 0
827     * StringUtils.compare(null , "a", true)  < 0
828     * StringUtils.compare(null , "a", false) > 0
829     * StringUtils.compare("a", null, true)   > 0
830     * StringUtils.compare("a", null, false)  < 0
831     * StringUtils.compare("abc", "abc", *)   = 0
832     * StringUtils.compare("a", "b", *)       < 0
833     * StringUtils.compare("b", "a", *)       > 0
834     * StringUtils.compare("a", "B", *)       > 0
835     * StringUtils.compare("ab", "abc", *)    < 0
836     * }</pre>
837     *
838     * @see String#compareTo(String)
839     * @param str1  the String to compare from
840     * @param str2  the String to compare to
841     * @param nullIsLess  whether consider {@code null} value less than non-{@code null} value
842     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2}
843     * @since 3.5
844     */
845    public static int compare(final String str1, final String str2, final boolean nullIsLess) {
846        if (str1 == str2) { // NOSONARLINT this intentionally uses == to allow for both null
847            return 0;
848        }
849        if (str1 == null) {
850            return nullIsLess ? -1 : 1;
851        }
852        if (str2 == null) {
853            return nullIsLess ? 1 : - 1;
854        }
855        return str1.compareTo(str2);
856    }
857
858    /**
859     * Compare two Strings lexicographically, ignoring case differences,
860     * as per {@link String#compareToIgnoreCase(String)}, returning :
861     * <ul>
862     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
863     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
864     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
865     * </ul>
866     *
867     * <p>This is a {@code null} safe version of :</p>
868     * <blockquote><pre>str1.compareToIgnoreCase(str2)</pre></blockquote>
869     *
870     * <p>{@code null} value is considered less than non-{@code null} value.
871     * Two {@code null} references are considered equal.
872     * Comparison is case insensitive.</p>
873     *
874     * <pre>{@code
875     * StringUtils.compareIgnoreCase(null, null)   = 0
876     * StringUtils.compareIgnoreCase(null , "a")   < 0
877     * StringUtils.compareIgnoreCase("a", null)    > 0
878     * StringUtils.compareIgnoreCase("abc", "abc") = 0
879     * StringUtils.compareIgnoreCase("abc", "ABC") = 0
880     * StringUtils.compareIgnoreCase("a", "b")     < 0
881     * StringUtils.compareIgnoreCase("b", "a")     > 0
882     * StringUtils.compareIgnoreCase("a", "B")     < 0
883     * StringUtils.compareIgnoreCase("A", "b")     < 0
884     * StringUtils.compareIgnoreCase("ab", "ABC")  < 0
885     * }</pre>
886     *
887     * @see #compareIgnoreCase(String, String, boolean)
888     * @see String#compareToIgnoreCase(String)
889     * @param str1  the String to compare from
890     * @param str2  the String to compare to
891     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2},
892     *          ignoring case differences.
893     * @since 3.5
894     * @deprecated Use {@link Strings#compare(String, String) Strings.CI.compare(String, String)}
895     */
896    @Deprecated
897    public static int compareIgnoreCase(final String str1, final String str2) {
898        return Strings.CI.compare(str1, str2);
899    }
900
901    /**
902     * Compare two Strings lexicographically, ignoring case differences,
903     * as per {@link String#compareToIgnoreCase(String)}, returning :
904     * <ul>
905     *  <li>{@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})</li>
906     *  <li>{@code int < 0}, if {@code str1} is less than {@code str2}</li>
907     *  <li>{@code int > 0}, if {@code str1} is greater than {@code str2}</li>
908     * </ul>
909     *
910     * <p>This is a {@code null} safe version of :</p>
911     * <blockquote><pre>str1.compareToIgnoreCase(str2)</pre></blockquote>
912     *
913     * <p>{@code null} inputs are handled according to the {@code nullIsLess} parameter.
914     * Two {@code null} references are considered equal.
915     * Comparison is case insensitive.</p>
916     *
917     * <pre>{@code
918     * StringUtils.compareIgnoreCase(null, null, *)     = 0
919     * StringUtils.compareIgnoreCase(null , "a", true)  < 0
920     * StringUtils.compareIgnoreCase(null , "a", false) > 0
921     * StringUtils.compareIgnoreCase("a", null, true)   > 0
922     * StringUtils.compareIgnoreCase("a", null, false)  < 0
923     * StringUtils.compareIgnoreCase("abc", "abc", *)   = 0
924     * StringUtils.compareIgnoreCase("abc", "ABC", *)   = 0
925     * StringUtils.compareIgnoreCase("a", "b", *)       < 0
926     * StringUtils.compareIgnoreCase("b", "a", *)       > 0
927     * StringUtils.compareIgnoreCase("a", "B", *)       < 0
928     * StringUtils.compareIgnoreCase("A", "b", *)       < 0
929     * StringUtils.compareIgnoreCase("ab", "abc", *)    < 0
930     * }</pre>
931     *
932     * @see String#compareToIgnoreCase(String)
933     * @param str1  the String to compare from
934     * @param str2  the String to compare to
935     * @param nullIsLess  whether consider {@code null} value less than non-{@code null} value
936     * @return &lt; 0, 0, &gt; 0, if {@code str1} is respectively less, equal ou greater than {@code str2},
937     *          ignoring case differences.
938     * @since 3.5
939     */
940    public static int compareIgnoreCase(final String str1, final String str2, final boolean nullIsLess) {
941        if (str1 == str2) { // NOSONARLINT this intentionally uses == to allow for both null
942            return 0;
943        }
944        if (str1 == null) {
945            return nullIsLess ? -1 : 1;
946        }
947        if (str2 == null) {
948            return nullIsLess ? 1 : - 1;
949        }
950        return str1.compareToIgnoreCase(str2);
951    }
952
953    /**
954     * Tests if CharSequence contains a search CharSequence, handling {@code null}.
955     * This method uses {@link String#indexOf(String)} if possible.
956     *
957     * <p>A {@code null} CharSequence will return {@code false}.</p>
958     *
959     * <pre>
960     * StringUtils.contains(null, *)     = false
961     * StringUtils.contains(*, null)     = false
962     * StringUtils.contains("", "")      = true
963     * StringUtils.contains("abc", "")   = true
964     * StringUtils.contains("abc", "a")  = true
965     * StringUtils.contains("abc", "z")  = false
966     * </pre>
967     *
968     * @param seq  the CharSequence to check, may be null
969     * @param searchSeq  the CharSequence to find, may be null
970     * @return true if the CharSequence contains the search CharSequence,
971     *  false if not or {@code null} string input
972     * @since 2.0
973     * @since 3.0 Changed signature from contains(String, String) to contains(CharSequence, CharSequence)
974     * @deprecated Use {@link Strings#contains(CharSequence, CharSequence) Strings.CS.contains(CharSequence, CharSequence)}
975     */
976    @Deprecated
977    public static boolean contains(final CharSequence seq, final CharSequence searchSeq) {
978        return Strings.CS.contains(seq, searchSeq);
979    }
980
981    /**
982     * Tests if CharSequence contains a search character, handling {@code null}.
983     * This method uses {@link String#indexOf(int)} if possible.
984     *
985     * <p>A {@code null} or empty ("") CharSequence will return {@code false}.</p>
986     *
987     * <pre>
988     * StringUtils.contains(null, *)    = false
989     * StringUtils.contains("", *)      = false
990     * StringUtils.contains("abc", 'a') = true
991     * StringUtils.contains("abc", 'z') = false
992     * </pre>
993     *
994     * @param seq  the CharSequence to check, may be null
995     * @param searchChar  the character to find
996     * @return true if the CharSequence contains the search character,
997     *  false if not or {@code null} string input
998     * @since 2.0
999     * @since 3.0 Changed signature from contains(String, int) to contains(CharSequence, int)
1000     */
1001    public static boolean contains(final CharSequence seq, final int searchChar) {
1002        if (isEmpty(seq)) {
1003            return false;
1004        }
1005        return CharSequenceUtils.indexOf(seq, searchChar, 0) >= 0;
1006    }
1007
1008    /**
1009     * Tests if the CharSequence contains any character in the given
1010     * set of characters.
1011     *
1012     * <p>A {@code null} CharSequence will return {@code false}.
1013     * A {@code null} or zero length search array will return {@code false}.</p>
1014     *
1015     * <pre>
1016     * StringUtils.containsAny(null, *)                  = false
1017     * StringUtils.containsAny("", *)                    = false
1018     * StringUtils.containsAny(*, null)                  = false
1019     * StringUtils.containsAny(*, [])                    = false
1020     * StringUtils.containsAny("zzabyycdxx", ['z', 'a']) = true
1021     * StringUtils.containsAny("zzabyycdxx", ['b', 'y']) = true
1022     * StringUtils.containsAny("zzabyycdxx", ['z', 'y']) = true
1023     * StringUtils.containsAny("aba", ['z'])             = false
1024     * </pre>
1025     *
1026     * @param cs  the CharSequence to check, may be null
1027     * @param searchChars  the chars to search for, may be null
1028     * @return the {@code true} if any of the chars are found,
1029     * {@code false} if no match or null input
1030     * @since 2.4
1031     * @since 3.0 Changed signature from containsAny(String, char[]) to containsAny(CharSequence, char...)
1032     */
1033    public static boolean containsAny(final CharSequence cs, final char... searchChars) {
1034        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
1035            return false;
1036        }
1037        final int csLength = cs.length();
1038        final int searchLength = searchChars.length;
1039        final int csLast = csLength - 1;
1040        final int searchLast = searchLength - 1;
1041        for (int i = 0; i < csLength; i++) {
1042            final char ch = cs.charAt(i);
1043            for (int j = 0; j < searchLength; j++) {
1044                if (searchChars[j] == ch) {
1045                    if (!Character.isHighSurrogate(ch) || j == searchLast || i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
1046                        return true;
1047                    }
1048                }
1049            }
1050        }
1051        return false;
1052    }
1053
1054    /**
1055     * Tests if the CharSequence contains any character in the given set of characters.
1056     *
1057     * <p>
1058     * A {@code null} CharSequence will return {@code false}. A {@code null} search CharSequence will return
1059     * {@code false}.
1060     * </p>
1061     *
1062     * <pre>
1063     * StringUtils.containsAny(null, *)               = false
1064     * StringUtils.containsAny("", *)                 = false
1065     * StringUtils.containsAny(*, null)               = false
1066     * StringUtils.containsAny(*, "")                 = false
1067     * StringUtils.containsAny("zzabyycdxx", "za")    = true
1068     * StringUtils.containsAny("zzabyycdxx", "by")    = true
1069     * StringUtils.containsAny("zzabyycdxx", "zy")    = true
1070     * StringUtils.containsAny("zzabyycdxx", "\tx")   = true
1071     * StringUtils.containsAny("zzabyycdxx", "$.#yF") = true
1072     * StringUtils.containsAny("aba", "z")            = false
1073     * </pre>
1074     *
1075     * @param cs
1076     *            the CharSequence to check, may be null
1077     * @param searchChars
1078     *            the chars to search for, may be null
1079     * @return the {@code true} if any of the chars are found, {@code false} if no match or null input
1080     * @since 2.4
1081     * @since 3.0 Changed signature from containsAny(String, String) to containsAny(CharSequence, CharSequence)
1082     */
1083    public static boolean containsAny(final CharSequence cs, final CharSequence searchChars) {
1084        if (searchChars == null) {
1085            return false;
1086        }
1087        return containsAny(cs, CharSequenceUtils.toCharArray(searchChars));
1088    }
1089
1090    /**
1091     * Tests if the CharSequence contains any of the CharSequences in the given array.
1092     *
1093     * <p>
1094     * A {@code null} {@code cs} CharSequence will return {@code false}. A {@code null} or zero length search array will
1095     * return {@code false}.
1096     * </p>
1097     *
1098     * <pre>
1099     * StringUtils.containsAny(null, *)            = false
1100     * StringUtils.containsAny("", *)              = false
1101     * StringUtils.containsAny(*, null)            = false
1102     * StringUtils.containsAny(*, [])              = false
1103     * StringUtils.containsAny("abcd", "ab", null) = true
1104     * StringUtils.containsAny("abcd", "ab", "cd") = true
1105     * StringUtils.containsAny("abc", "d", "abc")  = true
1106     * </pre>
1107     *
1108     * @param cs The CharSequence to check, may be null
1109     * @param searchCharSequences The array of CharSequences to search for, may be null. Individual CharSequences may be
1110     *        null as well.
1111     * @return {@code true} if any of the search CharSequences are found, {@code false} otherwise
1112     * @since 3.4
1113     * @deprecated Use {@link Strings#containsAny(CharSequence, CharSequence...) Strings.CS.containsAny(CharSequence, CharSequence...)}
1114     */
1115    @Deprecated
1116    public static boolean containsAny(final CharSequence cs, final CharSequence... searchCharSequences) {
1117        return Strings.CS.containsAny(cs, searchCharSequences);
1118    }
1119
1120    /**
1121     * Tests if the CharSequence contains any of the CharSequences in the given array, ignoring case.
1122     *
1123     * <p>
1124     * A {@code null} {@code cs} CharSequence will return {@code false}. A {@code null} or zero length search array will
1125     * return {@code false}.
1126     * </p>
1127     *
1128     * <pre>
1129     * StringUtils.containsAny(null, *)            = false
1130     * StringUtils.containsAny("", *)              = false
1131     * StringUtils.containsAny(*, null)            = false
1132     * StringUtils.containsAny(*, [])              = false
1133     * StringUtils.containsAny("abcd", "ab", null) = true
1134     * StringUtils.containsAny("abcd", "ab", "cd") = true
1135     * StringUtils.containsAny("abc", "d", "abc")  = true
1136     * StringUtils.containsAny("abc", "D", "ABC")  = true
1137     * StringUtils.containsAny("ABC", "d", "abc")  = true
1138     * </pre>
1139     *
1140     * @param cs The CharSequence to check, may be null
1141     * @param searchCharSequences The array of CharSequences to search for, may be null. Individual CharSequences may be
1142     *        null as well.
1143     * @return {@code true} if any of the search CharSequences are found, {@code false} otherwise
1144     * @since 3.12.0
1145     * @deprecated Use {@link Strings#containsAny(CharSequence, CharSequence...) Strings.CI.containsAny(CharSequence, CharSequence...)}
1146     */
1147    @Deprecated
1148    public static boolean containsAnyIgnoreCase(final CharSequence cs, final CharSequence... searchCharSequences) {
1149        return Strings.CI.containsAny(cs, searchCharSequences);
1150    }
1151
1152    /**
1153     * Tests if CharSequence contains a search CharSequence irrespective of case,
1154     * handling {@code null}. Case-insensitivity is defined as by
1155     * {@link String#equalsIgnoreCase(String)}.
1156     *
1157     * <p>A {@code null} CharSequence will return {@code false}.
1158     *
1159     * <pre>
1160     * StringUtils.containsIgnoreCase(null, *)    = false
1161     * StringUtils.containsIgnoreCase(*, null)    = false
1162     * StringUtils.containsIgnoreCase("", "")     = true
1163     * StringUtils.containsIgnoreCase("abc", "")  = true
1164     * StringUtils.containsIgnoreCase("abc", "a") = true
1165     * StringUtils.containsIgnoreCase("abc", "z") = false
1166     * StringUtils.containsIgnoreCase("abc", "A") = true
1167     * StringUtils.containsIgnoreCase("abc", "Z") = false
1168     * </pre>
1169     *
1170     * @param str  the CharSequence to check, may be null
1171     * @param searchStr  the CharSequence to find, may be null
1172     * @return true if the CharSequence contains the search CharSequence irrespective of
1173     * case or false if not or {@code null} string input
1174     * @since 3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence, CharSequence)
1175     * @deprecated Use {@link Strings#contains(CharSequence, CharSequence) Strings.CI.contains(CharSequence, CharSequence)}
1176     */
1177    @Deprecated
1178    public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
1179        return Strings.CI.contains(str, searchStr);
1180    }
1181
1182    /**
1183     * Tests that the CharSequence does not contain certain characters.
1184     *
1185     * <p>A {@code null} CharSequence will return {@code true}.
1186     * A {@code null} invalid character array will return {@code true}.
1187     * An empty CharSequence (length()=0) always returns true.</p>
1188     *
1189     * <pre>
1190     * StringUtils.containsNone(null, *)       = true
1191     * StringUtils.containsNone(*, null)       = true
1192     * StringUtils.containsNone("", *)         = true
1193     * StringUtils.containsNone("ab", '')      = true
1194     * StringUtils.containsNone("abab", 'xyz') = true
1195     * StringUtils.containsNone("ab1", 'xyz')  = true
1196     * StringUtils.containsNone("abz", 'xyz')  = false
1197     * </pre>
1198     *
1199     * @param cs  the CharSequence to check, may be null
1200     * @param searchChars  an array of invalid chars, may be null
1201     * @return true if it contains none of the invalid chars, or is null
1202     * @since 2.0
1203     * @since 3.0 Changed signature from containsNone(String, char[]) to containsNone(CharSequence, char...)
1204     */
1205    public static boolean containsNone(final CharSequence cs, final char... searchChars) {
1206        if (cs == null || searchChars == null) {
1207            return true;
1208        }
1209        final int csLen = cs.length();
1210        final int csLast = csLen - 1;
1211        final int searchLen = searchChars.length;
1212        final int searchLast = searchLen - 1;
1213        for (int i = 0; i < csLen; i++) {
1214            final char ch = cs.charAt(i);
1215            for (int j = 0; j < searchLen; j++) {
1216                if (searchChars[j] == ch) {
1217                    if (!Character.isHighSurrogate(ch) || j == searchLast || i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
1218                        return false;
1219                    }
1220                }
1221            }
1222        }
1223        return true;
1224    }
1225
1226    /**
1227     * Tests that the CharSequence does not contain certain characters.
1228     *
1229     * <p>A {@code null} CharSequence will return {@code true}.
1230     * A {@code null} invalid character array will return {@code true}.
1231     * An empty String ("") always returns true.</p>
1232     *
1233     * <pre>
1234     * StringUtils.containsNone(null, *)       = true
1235     * StringUtils.containsNone(*, null)       = true
1236     * StringUtils.containsNone("", *)         = true
1237     * StringUtils.containsNone("ab", "")      = true
1238     * StringUtils.containsNone("abab", "xyz") = true
1239     * StringUtils.containsNone("ab1", "xyz")  = true
1240     * StringUtils.containsNone("abz", "xyz")  = false
1241     * </pre>
1242     *
1243     * @param cs  the CharSequence to check, may be null
1244     * @param invalidChars  a String of invalid chars, may be null
1245     * @return true if it contains none of the invalid chars, or is null
1246     * @since 2.0
1247     * @since 3.0 Changed signature from containsNone(String, String) to containsNone(CharSequence, String)
1248     */
1249    public static boolean containsNone(final CharSequence cs, final String invalidChars) {
1250        if (invalidChars == null) {
1251            return true;
1252        }
1253        return containsNone(cs, invalidChars.toCharArray());
1254    }
1255
1256    /**
1257     * Tests if the CharSequence contains only certain characters.
1258     *
1259     * <p>A {@code null} CharSequence will return {@code false}.
1260     * A {@code null} valid character array will return {@code false}.
1261     * An empty CharSequence (length()=0) always returns {@code true}.</p>
1262     *
1263     * <pre>
1264     * StringUtils.containsOnly(null, *)       = false
1265     * StringUtils.containsOnly(*, null)       = false
1266     * StringUtils.containsOnly("", *)         = true
1267     * StringUtils.containsOnly("ab", '')      = false
1268     * StringUtils.containsOnly("abab", 'abc') = true
1269     * StringUtils.containsOnly("ab1", 'abc')  = false
1270     * StringUtils.containsOnly("abz", 'abc')  = false
1271     * </pre>
1272     *
1273     * @param cs  the String to check, may be null
1274     * @param valid  an array of valid chars, may be null
1275     * @return true if it only contains valid chars and is non-null
1276     * @since 3.0 Changed signature from containsOnly(String, char[]) to containsOnly(CharSequence, char...)
1277     */
1278    public static boolean containsOnly(final CharSequence cs, final char... valid) {
1279        // All these pre-checks are to maintain API with an older version
1280        if (valid == null || cs == null) {
1281            return false;
1282        }
1283        if (cs.length() == 0) {
1284            return true;
1285        }
1286        if (valid.length == 0) {
1287            return false;
1288        }
1289        return indexOfAnyBut(cs, valid) == INDEX_NOT_FOUND;
1290    }
1291
1292    /**
1293     * Tests if the CharSequence contains only certain characters.
1294     *
1295     * <p>A {@code null} CharSequence will return {@code false}.
1296     * A {@code null} valid character String will return {@code false}.
1297     * An empty String (length()=0) always returns {@code true}.</p>
1298     *
1299     * <pre>
1300     * StringUtils.containsOnly(null, *)       = false
1301     * StringUtils.containsOnly(*, null)       = false
1302     * StringUtils.containsOnly("", *)         = true
1303     * StringUtils.containsOnly("ab", "")      = false
1304     * StringUtils.containsOnly("abab", "abc") = true
1305     * StringUtils.containsOnly("ab1", "abc")  = false
1306     * StringUtils.containsOnly("abz", "abc")  = false
1307     * </pre>
1308     *
1309     * @param cs  the CharSequence to check, may be null
1310     * @param validChars  a String of valid chars, may be null
1311     * @return true if it only contains valid chars and is non-null
1312     * @since 2.0
1313     * @since 3.0 Changed signature from containsOnly(String, String) to containsOnly(CharSequence, String)
1314     */
1315    public static boolean containsOnly(final CharSequence cs, final String validChars) {
1316        if (cs == null || validChars == null) {
1317            return false;
1318        }
1319        return containsOnly(cs, validChars.toCharArray());
1320    }
1321
1322    /**
1323     * Tests whether the given CharSequence contains any whitespace characters.
1324     *
1325     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
1326     *
1327     * <pre>
1328     * StringUtils.containsWhitespace(null)       = false
1329     * StringUtils.containsWhitespace("")         = false
1330     * StringUtils.containsWhitespace("ab")       = false
1331     * StringUtils.containsWhitespace(" ab")      = true
1332     * StringUtils.containsWhitespace("a b")      = true
1333     * StringUtils.containsWhitespace("ab ")      = true
1334     * </pre>
1335     *
1336     * @param seq the CharSequence to check (may be {@code null})
1337     * @return {@code true} if the CharSequence is not empty and
1338     * contains at least 1 (breaking) whitespace character
1339     * @since 3.0
1340     */
1341    // From org.springframework.util.StringUtils, under Apache License 2.0
1342    public static boolean containsWhitespace(final CharSequence seq) {
1343        if (isEmpty(seq)) {
1344            return false;
1345        }
1346        final int strLen = seq.length();
1347        for (int i = 0; i < strLen; i++) {
1348            if (Character.isWhitespace(seq.charAt(i))) {
1349                return true;
1350            }
1351        }
1352        return false;
1353    }
1354
1355    private static void convertRemainingAccentCharacters(final StringBuilder decomposed) {
1356        for (int i = 0; i < decomposed.length(); i++) {
1357            final char charAt = decomposed.charAt(i);
1358            switch (charAt) {
1359            case '\u0141':
1360                decomposed.setCharAt(i, 'L');
1361                break;
1362            case '\u0142':
1363                decomposed.setCharAt(i, 'l');
1364                break;
1365            // D with stroke
1366            case '\u0110':
1367                // LATIN CAPITAL LETTER D WITH STROKE
1368                decomposed.setCharAt(i, 'D');
1369                break;
1370            case '\u0111':
1371                // LATIN SMALL LETTER D WITH STROKE
1372                decomposed.setCharAt(i, 'd');
1373                break;
1374            // I with bar
1375            case '\u0197':
1376                decomposed.setCharAt(i, 'I');
1377                break;
1378            case '\u0268':
1379                decomposed.setCharAt(i, 'i');
1380                break;
1381            case '\u1D7B':
1382                decomposed.setCharAt(i, 'I');
1383                break;
1384            case '\u1DA4':
1385                decomposed.setCharAt(i, 'i');
1386                break;
1387            case '\u1DA7':
1388                decomposed.setCharAt(i, 'I');
1389                break;
1390            // U with bar
1391            case '\u0244':
1392                // LATIN CAPITAL LETTER U BAR
1393                decomposed.setCharAt(i, 'U');
1394                break;
1395            case '\u0289':
1396                // LATIN SMALL LETTER U BAR
1397                decomposed.setCharAt(i, 'u');
1398                break;
1399            case '\u1D7E':
1400                // LATIN SMALL CAPITAL LETTER U WITH STROKE
1401                decomposed.setCharAt(i, 'U');
1402                break;
1403            case '\u1DB6':
1404                // MODIFIER LETTER SMALL U BAR
1405                decomposed.setCharAt(i, 'u');
1406                break;
1407            // T with stroke
1408            case '\u0166':
1409                // LATIN CAPITAL LETTER T WITH STROKE
1410                decomposed.setCharAt(i, 'T');
1411                break;
1412            case '\u0167':
1413                // LATIN SMALL LETTER T WITH STROKE
1414                decomposed.setCharAt(i, 't');
1415                break;
1416            default:
1417                break;
1418            }
1419        }
1420    }
1421
1422    /**
1423     * Counts how many times the char appears in the given string.
1424     *
1425     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
1426     *
1427     * <pre>
1428     * StringUtils.countMatches(null, *)     = 0
1429     * StringUtils.countMatches("", *)       = 0
1430     * StringUtils.countMatches("abba", 0)   = 0
1431     * StringUtils.countMatches("abba", 'a') = 2
1432     * StringUtils.countMatches("abba", 'b') = 2
1433     * StringUtils.countMatches("abba", 'x') = 0
1434     * </pre>
1435     *
1436     * @param str  the CharSequence to check, may be null
1437     * @param ch  the char to count
1438     * @return the number of occurrences, 0 if the CharSequence is {@code null}
1439     * @since 3.4
1440     */
1441    public static int countMatches(final CharSequence str, final char ch) {
1442        if (isEmpty(str)) {
1443            return 0;
1444        }
1445        int count = 0;
1446        // We could also call str.toCharArray() for faster lookups but that would generate more garbage.
1447        for (int i = 0; i < str.length(); i++) {
1448            if (ch == str.charAt(i)) {
1449                count++;
1450            }
1451        }
1452        return count;
1453    }
1454
1455    /**
1456     * Counts how many times the substring appears in the larger string.
1457     * Note that the code only counts non-overlapping matches.
1458     *
1459     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
1460     *
1461     * <pre>
1462     * StringUtils.countMatches(null, *)        = 0
1463     * StringUtils.countMatches("", *)          = 0
1464     * StringUtils.countMatches("abba", null)   = 0
1465     * StringUtils.countMatches("abba", "")     = 0
1466     * StringUtils.countMatches("abba", "a")    = 2
1467     * StringUtils.countMatches("abba", "ab")   = 1
1468     * StringUtils.countMatches("abba", "xxx")  = 0
1469     * StringUtils.countMatches("ababa", "aba") = 1
1470     * </pre>
1471     *
1472     * @param str  the CharSequence to check, may be null
1473     * @param sub  the substring to count, may be null
1474     * @return the number of occurrences, 0 if either CharSequence is {@code null}
1475     * @since 3.0 Changed signature from countMatches(String, String) to countMatches(CharSequence, CharSequence)
1476     */
1477    public static int countMatches(final CharSequence str, final CharSequence sub) {
1478        if (isEmpty(str) || isEmpty(sub)) {
1479            return 0;
1480        }
1481        int count = 0;
1482        int idx = 0;
1483        while ((idx = CharSequenceUtils.indexOf(str, sub, idx)) != INDEX_NOT_FOUND) {
1484            count++;
1485            idx += sub.length();
1486        }
1487        return count;
1488    }
1489
1490    /**
1491     * Returns either the passed in CharSequence, or if the CharSequence is {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or
1492     * {@code null}), the value of {@code defaultStr}.
1493     *
1494     * <p>
1495     * Whitespace is defined by {@link Character#isWhitespace(char)}.
1496     * </p>
1497     *
1498     * <pre>
1499     * StringUtils.defaultIfBlank(null, "NULL")  = "NULL"
1500     * StringUtils.defaultIfBlank("", "NULL")    = "NULL"
1501     * StringUtils.defaultIfBlank(" ", "NULL")   = "NULL"
1502     * StringUtils.defaultIfBlank("bat", "NULL") = "bat"
1503     * StringUtils.defaultIfBlank("", null)      = null
1504     * </pre>
1505     *
1506     * @param <T>        the specific kind of CharSequence
1507     * @param str        the CharSequence to check, may be null
1508     * @param defaultStr the default CharSequence to return if {@code str} is {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code""}) or
1509     *                   {@code null}); may be null
1510     * @return the passed in CharSequence, or the default
1511     * @see StringUtils#defaultString(String, String)
1512     * @see #isBlank(CharSequence)
1513     */
1514    public static <T extends CharSequence> T defaultIfBlank(final T str, final T defaultStr) {
1515        return isBlank(str) ? defaultStr : str;
1516    }
1517
1518    /**
1519     * Returns either the passed in CharSequence, or if the CharSequence is
1520     * empty or {@code null}, the value of {@code defaultStr}.
1521     *
1522     * <pre>
1523     * StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
1524     * StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
1525     * StringUtils.defaultIfEmpty(" ", "NULL")   = " "
1526     * StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
1527     * StringUtils.defaultIfEmpty("", null)      = null
1528     * </pre>
1529     * @param <T> the specific kind of CharSequence
1530     * @param str  the CharSequence to check, may be null
1531     * @param defaultStr  the default CharSequence to return
1532     *  if the input is empty ("") or {@code null}, may be null
1533     * @return the passed in CharSequence, or the default
1534     * @see StringUtils#defaultString(String, String)
1535     */
1536    public static <T extends CharSequence> T defaultIfEmpty(final T str, final T defaultStr) {
1537        return isEmpty(str) ? defaultStr : str;
1538    }
1539
1540    /**
1541     * Returns either the passed in String,
1542     * or if the String is {@code null}, an empty String ("").
1543     *
1544     * <pre>
1545     * StringUtils.defaultString(null)  = ""
1546     * StringUtils.defaultString("")    = ""
1547     * StringUtils.defaultString("bat") = "bat"
1548     * </pre>
1549     *
1550     * @see Objects#toString(Object, String)
1551     * @see String#valueOf(Object)
1552     * @param str  the String to check, may be null
1553     * @return the passed in String, or the empty String if it
1554     *  was {@code null}
1555     */
1556    public static String defaultString(final String str) {
1557        return Objects.toString(str, EMPTY);
1558    }
1559
1560    /**
1561     * Returns either the given String, or if the String is
1562     * {@code null}, {@code nullDefault}.
1563     *
1564     * <pre>
1565     * StringUtils.defaultString(null, "NULL")  = "NULL"
1566     * StringUtils.defaultString("", "NULL")    = ""
1567     * StringUtils.defaultString("bat", "NULL") = "bat"
1568     * </pre>
1569     * <p>
1570     * Since this is now provided by Java, instead call {@link Objects#toString(Object, String)}:
1571     * </p>
1572     * <pre>
1573     * Objects.toString(null, "NULL")  = "NULL"
1574     * Objects.toString("", "NULL")    = ""
1575     * Objects.toString("bat", "NULL") = "bat"
1576     * </pre>
1577     *
1578     * @see Objects#toString(Object, String)
1579     * @see String#valueOf(Object)
1580     * @param str  the String to check, may be null
1581     * @param nullDefault  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     * @deprecated Use {@link Objects#toString(Object, String)}
1585     */
1586    @Deprecated
1587    public static String defaultString(final String str, final String nullDefault) {
1588        return Objects.toString(str, nullDefault);
1589    }
1590
1591    /**
1592     * Deletes all whitespaces from a String as defined by
1593     * {@link Character#isWhitespace(char)}.
1594     *
1595     * <pre>
1596     * StringUtils.deleteWhitespace(null)         = null
1597     * StringUtils.deleteWhitespace("")           = ""
1598     * StringUtils.deleteWhitespace("abc")        = "abc"
1599     * StringUtils.deleteWhitespace("   ab  c  ") = "abc"
1600     * </pre>
1601     *
1602     * @param str  the String to delete whitespace from, may be null
1603     * @return the String without whitespaces, {@code null} if null String input
1604     */
1605    public static String deleteWhitespace(final String str) {
1606        if (isEmpty(str)) {
1607            return str;
1608        }
1609        final int sz = str.length();
1610        final char[] chs = new char[sz];
1611        int count = 0;
1612        for (int i = 0; i < sz; i++) {
1613            if (!Character.isWhitespace(str.charAt(i))) {
1614                chs[count++] = str.charAt(i);
1615            }
1616        }
1617        if (count == sz) {
1618            return str;
1619        }
1620        if (count == 0) {
1621            return EMPTY;
1622        }
1623        return new String(chs, 0, count);
1624    }
1625
1626    /**
1627     * Compares two Strings, and returns the portion where they differ.
1628     * More precisely, return the remainder of the second String,
1629     * starting from where it's different from the first. This means that
1630     * the difference between "abc" and "ab" is the empty String and not "c".
1631     *
1632     * <p>For example,
1633     * {@code difference("i am a machine", "i am a robot") -> "robot"}.</p>
1634     *
1635     * <pre>
1636     * StringUtils.difference(null, null)       = null
1637     * StringUtils.difference("", "")           = ""
1638     * StringUtils.difference("", "abc")        = "abc"
1639     * StringUtils.difference("abc", "")        = ""
1640     * StringUtils.difference("abc", "abc")     = ""
1641     * StringUtils.difference("abc", "ab")      = ""
1642     * StringUtils.difference("ab", "abxyz")    = "xyz"
1643     * StringUtils.difference("abcde", "abxyz") = "xyz"
1644     * StringUtils.difference("abcde", "xyz")   = "xyz"
1645     * </pre>
1646     *
1647     * @param str1  the first String, may be null
1648     * @param str2  the second String, may be null
1649     * @return the portion of str2 where it differs from str1; returns the
1650     * empty String if they are equal
1651     * @see #indexOfDifference(CharSequence,CharSequence)
1652     * @since 2.0
1653     */
1654    public static String difference(final String str1, final String str2) {
1655        if (str1 == null) {
1656            return str2;
1657        }
1658        if (str2 == null) {
1659            return str1;
1660        }
1661        final int at = indexOfDifference(str1, str2);
1662        if (at == INDEX_NOT_FOUND) {
1663            return EMPTY;
1664        }
1665        return str2.substring(at);
1666    }
1667
1668    /**
1669     * Tests if a CharSequence ends with a specified suffix.
1670     *
1671     * <p>{@code null}s are handled without exceptions. Two {@code null}
1672     * references are considered to be equal. The comparison is case-sensitive.</p>
1673     *
1674     * <pre>
1675     * StringUtils.endsWith(null, null)      = true
1676     * StringUtils.endsWith(null, "def")     = false
1677     * StringUtils.endsWith("abcdef", null)  = false
1678     * StringUtils.endsWith("abcdef", "def") = true
1679     * StringUtils.endsWith("ABCDEF", "def") = false
1680     * StringUtils.endsWith("ABCDEF", "cde") = false
1681     * StringUtils.endsWith("ABCDEF", "")    = true
1682     * </pre>
1683     *
1684     * @see String#endsWith(String)
1685     * @param str  the CharSequence to check, may be null
1686     * @param suffix the suffix to find, may be null
1687     * @return {@code true} if the CharSequence ends with the suffix, case-sensitive, or
1688     *  both {@code null}
1689     * @since 2.4
1690     * @since 3.0 Changed signature from endsWith(String, String) to endsWith(CharSequence, CharSequence)
1691     * @deprecated Use {@link Strings#endsWith(CharSequence, CharSequence) Strings.CS.endsWith(CharSequence, CharSequence)}
1692     */
1693    @Deprecated
1694    public static boolean endsWith(final CharSequence str, final CharSequence suffix) {
1695        return Strings.CS.endsWith(str, suffix);
1696    }
1697
1698    /**
1699     * Tests if a CharSequence ends with any of the provided case-sensitive suffixes.
1700     *
1701     * <pre>
1702     * StringUtils.endsWithAny(null, null)                  = false
1703     * StringUtils.endsWithAny(null, new String[] {"abc"})  = false
1704     * StringUtils.endsWithAny("abcxyz", null)              = false
1705     * StringUtils.endsWithAny("abcxyz", new String[] {""}) = true
1706     * StringUtils.endsWithAny("abcxyz", new String[] {"xyz"}) = true
1707     * StringUtils.endsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
1708     * StringUtils.endsWithAny("abcXYZ", "def", "XYZ")      = true
1709     * StringUtils.endsWithAny("abcXYZ", "def", "xyz")      = false
1710     * </pre>
1711     *
1712     * @param sequence  the CharSequence to check, may be null
1713     * @param searchStrings the case-sensitive CharSequences to find, may be empty or contain {@code null}
1714     * @see StringUtils#endsWith(CharSequence, CharSequence)
1715     * @return {@code true} if the input {@code sequence} is {@code null} AND no {@code searchStrings} are provided, or
1716     *   the input {@code sequence} ends in any of the provided case-sensitive {@code searchStrings}.
1717     * @since 3.0
1718     * @deprecated Use {@link Strings#endsWithAny(CharSequence, CharSequence...) Strings.CS.endsWithAny(CharSequence, CharSequence...)}
1719     */
1720    @Deprecated
1721    public static boolean endsWithAny(final CharSequence sequence, final CharSequence... searchStrings) {
1722        return Strings.CS.endsWithAny(sequence, searchStrings);
1723    }
1724
1725    /**
1726     * Case-insensitive check if a CharSequence ends with a specified suffix.
1727     *
1728     * <p>{@code null}s are handled without exceptions. Two {@code null}
1729     * references are considered to be equal. The comparison is case insensitive.</p>
1730     *
1731     * <pre>
1732     * StringUtils.endsWithIgnoreCase(null, null)      = true
1733     * StringUtils.endsWithIgnoreCase(null, "def")     = false
1734     * StringUtils.endsWithIgnoreCase("abcdef", null)  = false
1735     * StringUtils.endsWithIgnoreCase("abcdef", "def") = true
1736     * StringUtils.endsWithIgnoreCase("ABCDEF", "def") = true
1737     * StringUtils.endsWithIgnoreCase("ABCDEF", "cde") = false
1738     * </pre>
1739     *
1740     * @see String#endsWith(String)
1741     * @param str  the CharSequence to check, may be null
1742     * @param suffix the suffix to find, may be null
1743     * @return {@code true} if the CharSequence ends with the suffix, case-insensitive, or
1744     *  both {@code null}
1745     * @since 2.4
1746     * @since 3.0 Changed signature from endsWithIgnoreCase(String, String) to endsWithIgnoreCase(CharSequence, CharSequence)
1747     * @deprecated Use {@link Strings#endsWith(CharSequence, CharSequence) Strings.CS.endsWith(CharSequence, CharSequence)}
1748     */
1749    @Deprecated
1750    public static boolean endsWithIgnoreCase(final CharSequence str, final CharSequence suffix) {
1751        return Strings.CI.endsWith(str, suffix);
1752    }
1753
1754    /**
1755     * Compares two CharSequences, returning {@code true} if they represent
1756     * equal sequences of characters.
1757     *
1758     * <p>{@code null}s are handled without exceptions. Two {@code null}
1759     * references are considered to be equal. The comparison is <strong>case-sensitive</strong>.</p>
1760     *
1761     * <pre>
1762     * StringUtils.equals(null, null)   = true
1763     * StringUtils.equals(null, "abc")  = false
1764     * StringUtils.equals("abc", null)  = false
1765     * StringUtils.equals("abc", "abc") = true
1766     * StringUtils.equals("abc", "ABC") = false
1767     * </pre>
1768     *
1769     * @param cs1  the first CharSequence, may be {@code null}
1770     * @param cs2  the second CharSequence, may be {@code null}
1771     * @return {@code true} if the CharSequences are equal (case-sensitive), or both {@code null}
1772     * @since 3.0 Changed signature from equals(String, String) to equals(CharSequence, CharSequence)
1773     * @see Object#equals(Object)
1774     * @see #equalsIgnoreCase(CharSequence, CharSequence)
1775     * @deprecated Use {@link Strings#equals(CharSequence, CharSequence) Strings.CS.equals(CharSequence, CharSequence)}
1776     */
1777    @Deprecated
1778    public static boolean equals(final CharSequence cs1, final CharSequence cs2) {
1779        return Strings.CS.equals(cs1, cs2);
1780    }
1781
1782    /**
1783     * Compares given {@code string} to a CharSequences vararg of {@code searchStrings},
1784     * returning {@code true} if the {@code string} is equal to any of the {@code searchStrings}.
1785     *
1786     * <pre>
1787     * StringUtils.equalsAny(null, (CharSequence[]) null) = false
1788     * StringUtils.equalsAny(null, null, null)    = true
1789     * StringUtils.equalsAny(null, "abc", "def")  = false
1790     * StringUtils.equalsAny("abc", null, "def")  = false
1791     * StringUtils.equalsAny("abc", "abc", "def") = true
1792     * StringUtils.equalsAny("abc", "ABC", "DEF") = false
1793     * </pre>
1794     *
1795     * @param string to compare, may be {@code null}.
1796     * @param searchStrings a vararg of strings, may be {@code null}.
1797     * @return {@code true} if the string is equal (case-sensitive) to any other element of {@code searchStrings};
1798     * {@code false} if {@code searchStrings} is null or contains no matches.
1799     * @since 3.5
1800     * @deprecated Use {@link Strings#equalsAny(CharSequence, CharSequence...) Strings.CS.equalsAny(CharSequence, CharSequence...)}
1801     */
1802    @Deprecated
1803    public static boolean equalsAny(final CharSequence string, final CharSequence... searchStrings) {
1804        return Strings.CS.equalsAny(string, searchStrings);
1805    }
1806
1807    /**
1808     * Compares given {@code string} to a CharSequences vararg of {@code searchStrings},
1809     * returning {@code true} if the {@code string} is equal to any of the {@code searchStrings}, ignoring case.
1810     *
1811     * <pre>
1812     * StringUtils.equalsAnyIgnoreCase(null, (CharSequence[]) null) = false
1813     * StringUtils.equalsAnyIgnoreCase(null, null, null)    = true
1814     * StringUtils.equalsAnyIgnoreCase(null, "abc", "def")  = false
1815     * StringUtils.equalsAnyIgnoreCase("abc", null, "def")  = false
1816     * StringUtils.equalsAnyIgnoreCase("abc", "abc", "def") = true
1817     * StringUtils.equalsAnyIgnoreCase("abc", "ABC", "DEF") = true
1818     * </pre>
1819     *
1820     * @param string to compare, may be {@code null}.
1821     * @param searchStrings a vararg of strings, may be {@code null}.
1822     * @return {@code true} if the string is equal (case-insensitive) to any other element of {@code searchStrings};
1823     * {@code false} if {@code searchStrings} is null or contains no matches.
1824     * @since 3.5
1825     * @deprecated Use {@link Strings#equalsAny(CharSequence, CharSequence...) Strings.CI-.equalsAny(CharSequence, CharSequence...)}
1826     */
1827    @Deprecated
1828    public static boolean equalsAnyIgnoreCase(final CharSequence string, final CharSequence... searchStrings) {
1829        return Strings.CI.equalsAny(string, searchStrings);
1830    }
1831
1832    /**
1833     * Compares two CharSequences, returning {@code true} if they represent
1834     * equal sequences of characters, ignoring case.
1835     *
1836     * <p>{@code null}s are handled without exceptions. Two {@code null}
1837     * references are considered equal. The comparison is <strong>case insensitive</strong>.</p>
1838     *
1839     * <pre>
1840     * StringUtils.equalsIgnoreCase(null, null)   = true
1841     * StringUtils.equalsIgnoreCase(null, "abc")  = false
1842     * StringUtils.equalsIgnoreCase("abc", null)  = false
1843     * StringUtils.equalsIgnoreCase("abc", "abc") = true
1844     * StringUtils.equalsIgnoreCase("abc", "ABC") = true
1845     * </pre>
1846     *
1847     * @param cs1  the first CharSequence, may be {@code null}
1848     * @param cs2  the second CharSequence, may be {@code null}
1849     * @return {@code true} if the CharSequences are equal (case-insensitive), or both {@code null}
1850     * @since 3.0 Changed signature from equalsIgnoreCase(String, String) to equalsIgnoreCase(CharSequence, CharSequence)
1851     * @see #equals(CharSequence, CharSequence)
1852     * @deprecated Use {@link Strings#equals(CharSequence, CharSequence) Strings.CI.equals(CharSequence, CharSequence)}
1853     */
1854    @Deprecated
1855    public static boolean equalsIgnoreCase(final CharSequence cs1, final CharSequence cs2) {
1856        return Strings.CI.equals(cs1, cs2);
1857    }
1858
1859    /**
1860     * Returns the first value in the array which is not empty (""),
1861     * {@code null} or whitespace only.
1862     *
1863     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
1864     *
1865     * <p>If all values are blank or the array is {@code null}
1866     * or empty then {@code null} is returned.</p>
1867     *
1868     * <pre>
1869     * StringUtils.firstNonBlank(null, null, null)     = null
1870     * StringUtils.firstNonBlank(null, "", " ")        = null
1871     * StringUtils.firstNonBlank("abc")                = "abc"
1872     * StringUtils.firstNonBlank(null, "xyz")          = "xyz"
1873     * StringUtils.firstNonBlank(null, "", " ", "xyz") = "xyz"
1874     * StringUtils.firstNonBlank(null, "xyz", "abc")   = "xyz"
1875     * StringUtils.firstNonBlank()                     = null
1876     * </pre>
1877     *
1878     * @param <T> the specific kind of CharSequence
1879     * @param values  the values to test, may be {@code null} or empty
1880     * @return the first value from {@code values} which is not blank,
1881     *  or {@code null} if there are no non-blank values
1882     * @since 3.8
1883     */
1884    @SafeVarargs
1885    public static <T extends CharSequence> T firstNonBlank(final T... values) {
1886        if (values != null) {
1887            for (final T val : values) {
1888                if (isNotBlank(val)) {
1889                    return val;
1890                }
1891            }
1892        }
1893        return null;
1894    }
1895
1896    /**
1897     * Returns the first value in the array which is not empty.
1898     *
1899     * <p>If all values are empty or the array is {@code null}
1900     * or empty then {@code null} is returned.</p>
1901     *
1902     * <pre>
1903     * StringUtils.firstNonEmpty(null, null, null)   = null
1904     * StringUtils.firstNonEmpty(null, null, "")     = null
1905     * StringUtils.firstNonEmpty(null, "", " ")      = " "
1906     * StringUtils.firstNonEmpty("abc")              = "abc"
1907     * StringUtils.firstNonEmpty(null, "xyz")        = "xyz"
1908     * StringUtils.firstNonEmpty("", "xyz")          = "xyz"
1909     * StringUtils.firstNonEmpty(null, "xyz", "abc") = "xyz"
1910     * StringUtils.firstNonEmpty()                   = null
1911     * </pre>
1912     *
1913     * @param <T> the specific kind of CharSequence
1914     * @param values  the values to test, may be {@code null} or empty
1915     * @return the first value from {@code values} which is not empty,
1916     *  or {@code null} if there are no non-empty values
1917     * @since 3.8
1918     */
1919    @SafeVarargs
1920    public static <T extends CharSequence> T firstNonEmpty(final T... values) {
1921        if (values != null) {
1922            for (final T val : values) {
1923                if (isNotEmpty(val)) {
1924                    return val;
1925                }
1926            }
1927        }
1928        return null;
1929    }
1930
1931    /**
1932     * Calls {@link String#getBytes(Charset)} in a null-safe manner.
1933     *
1934     * @param string input string
1935     * @param charset The {@link Charset} to encode the {@link String}. If null, then use the default Charset.
1936     * @return The empty byte[] if {@code string} is null, the result of {@link String#getBytes(Charset)} otherwise.
1937     * @see String#getBytes(Charset)
1938     * @since 3.10
1939     */
1940    public static byte[] getBytes(final String string, final Charset charset) {
1941        return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharset(charset));
1942    }
1943
1944    /**
1945     * Calls {@link String#getBytes(String)} in a null-safe manner.
1946     *
1947     * @param string input string
1948     * @param charset The {@link Charset} name to encode the {@link String}. If null, then use the default Charset.
1949     * @return The empty byte[] if {@code string} is null, the result of {@link String#getBytes(String)} otherwise.
1950     * @throws UnsupportedEncodingException Thrown when the named charset is not supported.
1951     * @see String#getBytes(String)
1952     * @since 3.10
1953     */
1954    public static byte[] getBytes(final String string, final String charset) throws UnsupportedEncodingException {
1955        return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharsetName(charset));
1956    }
1957
1958    /**
1959     * Compares all Strings in an array and returns the initial sequence of
1960     * characters that is common to all of them.
1961     *
1962     * <p>For example,
1963     * {@code getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) -&gt; "i am a "}</p>
1964     *
1965     * <pre>
1966     * StringUtils.getCommonPrefix(null)                             = ""
1967     * StringUtils.getCommonPrefix(new String[] {})                  = ""
1968     * StringUtils.getCommonPrefix(new String[] {"abc"})             = "abc"
1969     * StringUtils.getCommonPrefix(new String[] {null, null})        = ""
1970     * StringUtils.getCommonPrefix(new String[] {"", ""})            = ""
1971     * StringUtils.getCommonPrefix(new String[] {"", null})          = ""
1972     * StringUtils.getCommonPrefix(new String[] {"abc", null, null}) = ""
1973     * StringUtils.getCommonPrefix(new String[] {null, null, "abc"}) = ""
1974     * StringUtils.getCommonPrefix(new String[] {"", "abc"})         = ""
1975     * StringUtils.getCommonPrefix(new String[] {"abc", ""})         = ""
1976     * StringUtils.getCommonPrefix(new String[] {"abc", "abc"})      = "abc"
1977     * StringUtils.getCommonPrefix(new String[] {"abc", "a"})        = "a"
1978     * StringUtils.getCommonPrefix(new String[] {"ab", "abxyz"})     = "ab"
1979     * StringUtils.getCommonPrefix(new String[] {"abcde", "abxyz"})  = "ab"
1980     * StringUtils.getCommonPrefix(new String[] {"abcde", "xyz"})    = ""
1981     * StringUtils.getCommonPrefix(new String[] {"xyz", "abcde"})    = ""
1982     * StringUtils.getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) = "i am a "
1983     * </pre>
1984     *
1985     * @param strs  array of String objects, entries may be null
1986     * @return the initial sequence of characters that are common to all Strings
1987     * in the array; empty String if the array is null, the elements are all null
1988     * or if there is no common prefix.
1989     * @since 2.4
1990     */
1991    public static String getCommonPrefix(final String... strs) {
1992        if (ArrayUtils.isEmpty(strs)) {
1993            return EMPTY;
1994        }
1995        final int smallestIndexOfDiff = indexOfDifference(strs);
1996        if (smallestIndexOfDiff == INDEX_NOT_FOUND) {
1997            // all strings were identical
1998            if (strs[0] == null) {
1999                return EMPTY;
2000            }
2001            return strs[0];
2002        }
2003        if (smallestIndexOfDiff == 0) {
2004            // there were no common initial characters
2005            return EMPTY;
2006        }
2007        // we found a common initial character sequence
2008        return strs[0].substring(0, smallestIndexOfDiff);
2009    }
2010
2011    /**
2012     * Checks if a String {@code str} contains Unicode digits,
2013     * if yes then concatenate all the digits in {@code str} and return it as a String.
2014     *
2015     * <p>An empty ("") String will be returned if no digits found in {@code str}.</p>
2016     *
2017     * <pre>
2018     * StringUtils.getDigits(null)                 = null
2019     * StringUtils.getDigits("")                   = ""
2020     * StringUtils.getDigits("abc")                = ""
2021     * StringUtils.getDigits("1000$")              = "1000"
2022     * StringUtils.getDigits("1123~45")            = "112345"
2023     * StringUtils.getDigits("(541) 754-3010")     = "5417543010"
2024     * StringUtils.getDigits("\u0967\u0968\u0969") = "\u0967\u0968\u0969"
2025     * </pre>
2026     *
2027     * @param str the String to extract digits from, may be null
2028     * @return String with only digits,
2029     *           or an empty ("") String if no digits found,
2030     *           or {@code null} String if {@code str} is null
2031     * @since 3.6
2032     */
2033    public static String getDigits(final String str) {
2034        if (isEmpty(str)) {
2035            return str;
2036        }
2037        final int sz = str.length();
2038        final StringBuilder strDigits = new StringBuilder(sz);
2039        for (int i = 0; i < sz; i++) {
2040            final char tempChar = str.charAt(i);
2041            if (Character.isDigit(tempChar)) {
2042                strDigits.append(tempChar);
2043            }
2044        }
2045        return strDigits.toString();
2046    }
2047
2048    /**
2049     * Find the Fuzzy Distance which indicates the similarity score between two Strings.
2050     *
2051     * <p>This string matching algorithm is similar to the algorithms of editors such as Sublime Text,
2052     * TextMate, Atom and others. One point is given for every matched character. Subsequent
2053     * matches yield two bonus points. A higher score indicates a higher similarity.</p>
2054     *
2055     * <pre>
2056     * StringUtils.getFuzzyDistance(null, null, null)                                    = IllegalArgumentException
2057     * StringUtils.getFuzzyDistance("", "", Locale.ENGLISH)                              = 0
2058     * StringUtils.getFuzzyDistance("Workshop", "b", Locale.ENGLISH)                     = 0
2059     * StringUtils.getFuzzyDistance("Room", "o", Locale.ENGLISH)                         = 1
2060     * StringUtils.getFuzzyDistance("Workshop", "w", Locale.ENGLISH)                     = 1
2061     * StringUtils.getFuzzyDistance("Workshop", "ws", Locale.ENGLISH)                    = 2
2062     * StringUtils.getFuzzyDistance("Workshop", "wo", Locale.ENGLISH)                    = 4
2063     * StringUtils.getFuzzyDistance("Apache Software Foundation", "asf", Locale.ENGLISH) = 3
2064     * </pre>
2065     *
2066     * @param term a full term that should be matched against, must not be null
2067     * @param query the query that will be matched against a term, must not be null
2068     * @param locale This string matching logic is case-insensitive. A locale is necessary to normalize
2069     *  both Strings to lower case.
2070     * @return result score
2071     * @throws IllegalArgumentException if either String input {@code null} or Locale input {@code null}
2072     * @since 3.4
2073     * @deprecated As of 3.6, use Apache Commons Text
2074     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/FuzzyScore.html">
2075     * FuzzyScore</a> instead
2076     */
2077    @Deprecated
2078    public static int getFuzzyDistance(final CharSequence term, final CharSequence query, final Locale locale) {
2079        if (term == null || query == null) {
2080            throw new IllegalArgumentException("Strings must not be null");
2081        }
2082        if (locale == null) {
2083            throw new IllegalArgumentException("Locale must not be null");
2084        }
2085
2086        // fuzzy logic is case-insensitive. We normalize the Strings to lower
2087        // case right from the start. Turning characters to lower case
2088        // via Character.toLowerCase(char) is unfortunately insufficient
2089        // as it does not accept a locale.
2090        final String termLowerCase = term.toString().toLowerCase(locale);
2091        final String queryLowerCase = query.toString().toLowerCase(locale);
2092
2093        // the resulting score
2094        int score = 0;
2095
2096        // the position in the term which will be scanned next for potential
2097        // query character matches
2098        int termIndex = 0;
2099
2100        // index of the previously matched character in the term
2101        int previousMatchingCharacterIndex = Integer.MIN_VALUE;
2102
2103        for (int queryIndex = 0; queryIndex < queryLowerCase.length(); queryIndex++) {
2104            final char queryChar = queryLowerCase.charAt(queryIndex);
2105
2106            boolean termCharacterMatchFound = false;
2107            for (; termIndex < termLowerCase.length() && !termCharacterMatchFound; termIndex++) {
2108                final char termChar = termLowerCase.charAt(termIndex);
2109
2110                if (queryChar == termChar) {
2111                    // simple character matches result in one point
2112                    score++;
2113
2114                    // subsequent character matches further improve
2115                    // the score.
2116                    if (previousMatchingCharacterIndex + 1 == termIndex) {
2117                        score += 2;
2118                    }
2119
2120                    previousMatchingCharacterIndex = termIndex;
2121
2122                    // we can leave the nested loop. Every character in the
2123                    // query can match at most one character in the term.
2124                    termCharacterMatchFound = true;
2125                }
2126            }
2127        }
2128
2129        return score;
2130    }
2131
2132    /**
2133     * Returns either the passed in CharSequence, or if the CharSequence is {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or
2134     * {@code null}), the value supplied by {@code defaultStrSupplier}.
2135     *
2136     * <p>
2137     * Whitespace is defined by {@link Character#isWhitespace(char)}.
2138     * </p>
2139     *
2140     * <p>
2141     * Caller responsible for thread-safety and exception handling of default value supplier
2142     * </p>
2143     *
2144     * <pre>
2145     * {@code
2146     * StringUtils.getIfBlank(null, () -> "NULL")   = "NULL"
2147     * StringUtils.getIfBlank("", () -> "NULL")     = "NULL"
2148     * StringUtils.getIfBlank(" ", () -> "NULL")    = "NULL"
2149     * StringUtils.getIfBlank("bat", () -> "NULL")  = "bat"
2150     * StringUtils.getIfBlank("", () -> null)       = null
2151     * StringUtils.getIfBlank("", null)             = null
2152     * }</pre>
2153     *
2154     * @param <T>             the specific kind of CharSequence
2155     * @param str             the CharSequence to check, may be null
2156     * @param defaultSupplier the supplier of default CharSequence to return if the input is {@link #isBlank(CharSequence) blank} (whitespaces, empty
2157     *                        ({@code ""}) or {@code null}); may be null
2158     * @return the passed in CharSequence, or the default
2159     * @see StringUtils#defaultString(String, String)
2160     * @see #isBlank(CharSequence)
2161     * @since 3.10
2162     */
2163    public static <T extends CharSequence> T getIfBlank(final T str, final Supplier<T> defaultSupplier) {
2164        return isBlank(str) ? Suppliers.get(defaultSupplier) : str;
2165    }
2166
2167    /**
2168     * Returns either the passed in CharSequence, or if the CharSequence is
2169     * empty or {@code null}, the value supplied by {@code defaultStrSupplier}.
2170     *
2171     * <p>Caller responsible for thread-safety and exception handling of default value supplier</p>
2172     *
2173     * <pre>
2174     * {@code
2175     * StringUtils.getIfEmpty(null, () -> "NULL")    = "NULL"
2176     * StringUtils.getIfEmpty("", () -> "NULL")      = "NULL"
2177     * StringUtils.getIfEmpty(" ", () -> "NULL")     = " "
2178     * StringUtils.getIfEmpty("bat", () -> "NULL")   = "bat"
2179     * StringUtils.getIfEmpty("", () -> null)        = null
2180     * StringUtils.getIfEmpty("", null)              = null
2181     * }
2182     * </pre>
2183     * @param <T> the specific kind of CharSequence
2184     * @param str  the CharSequence to check, may be null
2185     * @param defaultSupplier  the supplier of default CharSequence to return
2186     *  if the input is empty ("") or {@code null}, may be null
2187     * @return the passed in CharSequence, or the default
2188     * @see StringUtils#defaultString(String, String)
2189     * @since 3.10
2190     */
2191    public static <T extends CharSequence> T getIfEmpty(final T str, final Supplier<T> defaultSupplier) {
2192        return isEmpty(str) ? Suppliers.get(defaultSupplier) : str;
2193    }
2194
2195    /**
2196     * Find the Jaro Winkler Distance which indicates the similarity score between two Strings.
2197     *
2198     * <p>The Jaro measure is the weighted sum of percentage of matched characters from each file and transposed characters.
2199     * Winkler increased this measure for matching initial characters.</p>
2200     *
2201     * <p>This implementation is based on the Jaro Winkler similarity algorithm
2202     * from <a href="https://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance">https://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance</a>.</p>
2203     *
2204     * <pre>
2205     * StringUtils.getJaroWinklerDistance(null, null)          = IllegalArgumentException
2206     * StringUtils.getJaroWinklerDistance("", "")              = 0.0
2207     * StringUtils.getJaroWinklerDistance("", "a")             = 0.0
2208     * StringUtils.getJaroWinklerDistance("aaapppp", "")       = 0.0
2209     * StringUtils.getJaroWinklerDistance("frog", "fog")       = 0.93
2210     * StringUtils.getJaroWinklerDistance("fly", "ant")        = 0.0
2211     * StringUtils.getJaroWinklerDistance("elephant", "hippo") = 0.44
2212     * StringUtils.getJaroWinklerDistance("hippo", "elephant") = 0.44
2213     * StringUtils.getJaroWinklerDistance("hippo", "zzzzzzzz") = 0.0
2214     * StringUtils.getJaroWinklerDistance("hello", "hallo")    = 0.88
2215     * StringUtils.getJaroWinklerDistance("ABC Corporation", "ABC Corp") = 0.93
2216     * StringUtils.getJaroWinklerDistance("D N H Enterprises Inc", "D &amp; H Enterprises, Inc.") = 0.95
2217     * StringUtils.getJaroWinklerDistance("My Gym Children's Fitness Center", "My Gym. Childrens Fitness") = 0.92
2218     * StringUtils.getJaroWinklerDistance("PENNSYLVANIA", "PENNCISYLVNIA") = 0.88
2219     * </pre>
2220     *
2221     * @param first the first String, must not be null
2222     * @param second the second String, must not be null
2223     * @return result distance
2224     * @throws IllegalArgumentException if either String input {@code null}
2225     * @since 3.3
2226     * @deprecated As of 3.6, use Apache Commons Text
2227     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/JaroWinklerDistance.html">
2228     * JaroWinklerDistance</a> instead
2229     */
2230    @Deprecated
2231    public static double getJaroWinklerDistance(final CharSequence first, final CharSequence second) {
2232        final double DEFAULT_SCALING_FACTOR = 0.1;
2233
2234        if (first == null || second == null) {
2235            throw new IllegalArgumentException("Strings must not be null");
2236        }
2237
2238        final int[] mtp = matches(first, second);
2239        final double m = mtp[0];
2240        if (m == 0) {
2241            return 0D;
2242        }
2243        final double j = (m / first.length() + m / second.length() + (m - mtp[1]) / m) / 3;
2244        final double jw = j < 0.7D ? j : j + Math.min(DEFAULT_SCALING_FACTOR, 1D / mtp[3]) * mtp[2] * (1D - j);
2245        return Math.round(jw * 100.0D) / 100.0D;
2246    }
2247
2248    /**
2249     * Find the Levenshtein distance between two Strings.
2250     *
2251     * <p>This is the number of changes needed to change one String into
2252     * another, where each change is a single character modification (deletion,
2253     * insertion or substitution).</p>
2254     *
2255     * <p>The implementation uses a single-dimensional array of length s.length() + 1. See
2256     * <a href="https://blog.softwx.net/2014/12/optimizing-levenshtein-algorithm-in-c.html">
2257     * https://blog.softwx.net/2014/12/optimizing-levenshtein-algorithm-in-c.html</a> for details.</p>
2258     *
2259     * <pre>
2260     * StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
2261     * StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
2262     * StringUtils.getLevenshteinDistance("", "")              = 0
2263     * StringUtils.getLevenshteinDistance("", "a")             = 1
2264     * StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
2265     * StringUtils.getLevenshteinDistance("frog", "fog")       = 1
2266     * StringUtils.getLevenshteinDistance("fly", "ant")        = 3
2267     * StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
2268     * StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
2269     * StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
2270     * StringUtils.getLevenshteinDistance("hello", "hallo")    = 1
2271     * </pre>
2272     *
2273     * @param s  the first String, must not be null
2274     * @param t  the second String, must not be null
2275     * @return result distance
2276     * @throws IllegalArgumentException if either String input {@code null}
2277     * @since 3.0 Changed signature from getLevenshteinDistance(String, String) to
2278     * getLevenshteinDistance(CharSequence, CharSequence)
2279     * @deprecated As of 3.6, use Apache Commons Text
2280     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/LevenshteinDistance.html">
2281     * LevenshteinDistance</a> instead
2282     */
2283    @Deprecated
2284    public static int getLevenshteinDistance(CharSequence s, CharSequence t) {
2285        if (s == null || t == null) {
2286            throw new IllegalArgumentException("Strings must not be null");
2287        }
2288
2289        int n = s.length();
2290        int m = t.length();
2291
2292        if (n == 0) {
2293            return m;
2294        }
2295        if (m == 0) {
2296            return n;
2297        }
2298
2299        if (n > m) {
2300            // swap the input strings to consume less memory
2301            final CharSequence tmp = s;
2302            s = t;
2303            t = tmp;
2304            n = m;
2305            m = t.length();
2306        }
2307
2308        final int[] p = new int[n + 1];
2309        // indexes into strings s and t
2310        int i; // iterates through s
2311        int j; // iterates through t
2312        int upperleft;
2313        int upper;
2314
2315        char jOfT; // jth character of t
2316        int cost;
2317
2318        for (i = 0; i <= n; i++) {
2319            p[i] = i;
2320        }
2321
2322        for (j = 1; j <= m; j++) {
2323            upperleft = p[0];
2324            jOfT = t.charAt(j - 1);
2325            p[0] = j;
2326
2327            for (i = 1; i <= n; i++) {
2328                upper = p[i];
2329                cost = s.charAt(i - 1) == jOfT ? 0 : 1;
2330                // minimum of cell to the left+1, to the top+1, diagonally left and up +cost
2331                p[i] = Math.min(Math.min(p[i - 1] + 1, p[i] + 1), upperleft + cost);
2332                upperleft = upper;
2333            }
2334        }
2335
2336        return p[n];
2337    }
2338
2339    /**
2340     * Find the Levenshtein distance between two Strings if it's less than or equal to a given
2341     * threshold.
2342     *
2343     * <p>This is the number of changes needed to change one String into
2344     * another, where each change is a single character modification (deletion,
2345     * insertion or substitution).</p>
2346     *
2347     * <p>This implementation follows from Algorithms on Strings, Trees and Sequences by Dan Gusfield
2348     * and Chas Emerick's implementation of the Levenshtein distance algorithm from
2349     * <a href="https://web.archive.org/web/20120212021906/http%3A//www.merriampark.com/ld.htm">http://www.merriampark.com/ld.htm</a></p>
2350     *
2351     * <pre>
2352     * StringUtils.getLevenshteinDistance(null, *, *)             = IllegalArgumentException
2353     * StringUtils.getLevenshteinDistance(*, null, *)             = IllegalArgumentException
2354     * StringUtils.getLevenshteinDistance(*, *, -1)               = IllegalArgumentException
2355     * StringUtils.getLevenshteinDistance("", "", 0)              = 0
2356     * StringUtils.getLevenshteinDistance("aaapppp", "", 8)       = 7
2357     * StringUtils.getLevenshteinDistance("aaapppp", "", 7)       = 7
2358     * StringUtils.getLevenshteinDistance("aaapppp", "", 6))      = -1
2359     * StringUtils.getLevenshteinDistance("elephant", "hippo", 7) = 7
2360     * StringUtils.getLevenshteinDistance("elephant", "hippo", 6) = -1
2361     * StringUtils.getLevenshteinDistance("hippo", "elephant", 7) = 7
2362     * StringUtils.getLevenshteinDistance("hippo", "elephant", 6) = -1
2363     * </pre>
2364     *
2365     * @param s  the first String, must not be null
2366     * @param t  the second String, must not be null
2367     * @param threshold the target threshold, must not be negative
2368     * @return result distance, or {@code -1} if the distance would be greater than the threshold
2369     * @throws IllegalArgumentException if either String input {@code null} or negative threshold
2370     * @deprecated As of 3.6, use Apache Commons Text
2371     * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/similarity/LevenshteinDistance.html">
2372     * LevenshteinDistance</a> instead
2373     */
2374    @Deprecated
2375    public static int getLevenshteinDistance(CharSequence s, CharSequence t, final int threshold) {
2376        if (s == null || t == null) {
2377            throw new IllegalArgumentException("Strings must not be null");
2378        }
2379        if (threshold < 0) {
2380            throw new IllegalArgumentException("Threshold must not be negative");
2381        }
2382
2383        /*
2384        This implementation only computes the distance if it's less than or equal to the
2385        threshold value, returning -1 if it's greater.  The advantage is performance: unbounded
2386        distance is O(nm), but a bound of k allows us to reduce it to O(km) time by only
2387        computing a diagonal stripe of width 2k + 1 of the cost table.
2388        It is also possible to use this to compute the unbounded Levenshtein distance by starting
2389        the threshold at 1 and doubling each time until the distance is found; this is O(dm), where
2390        d is the distance.
2391
2392        One subtlety comes from needing to ignore entries on the border of our stripe
2393        eg.
2394        p[] = |#|#|#|*
2395        d[] =  *|#|#|#|
2396        We must ignore the entry to the left of the leftmost member
2397        We must ignore the entry above the rightmost member
2398
2399        Another subtlety comes from our stripe running off the matrix if the strings aren't
2400        of the same size.  Since string s is always swapped to be the shorter of the two,
2401        the stripe will always run off to the upper right instead of the lower left of the matrix.
2402
2403        As a concrete example, suppose s is of length 5, t is of length 7, and our threshold is 1.
2404        In this case we're going to walk a stripe of length 3.  The matrix would look like so:
2405
2406           1 2 3 4 5
2407        1 |#|#| | | |
2408        2 |#|#|#| | |
2409        3 | |#|#|#| |
2410        4 | | |#|#|#|
2411        5 | | | |#|#|
2412        6 | | | | |#|
2413        7 | | | | | |
2414
2415        Note how the stripe leads off the table as there is no possible way to turn a string of length 5
2416        into one of length 7 in edit distance of 1.
2417
2418        Additionally, this implementation decreases memory usage by using two
2419        single-dimensional arrays and swapping them back and forth instead of allocating
2420        an entire n by m matrix.  This requires a few minor changes, such as immediately returning
2421        when it's detected that the stripe has run off the matrix and initially filling the arrays with
2422        large values so that entries we don't compute are ignored.
2423
2424        See Algorithms on Strings, Trees and Sequences by Dan Gusfield for some discussion.
2425         */
2426
2427        int n = s.length(); // length of s
2428        int m = t.length(); // length of t
2429
2430        // if one string is empty, the edit distance is necessarily the length of the other
2431        if (n == 0) {
2432            return m <= threshold ? m : -1;
2433        }
2434        if (m == 0) {
2435            return n <= threshold ? n : -1;
2436        }
2437        if (Math.abs(n - m) > threshold) {
2438            // no need to calculate the distance if the length difference is greater than the threshold
2439            return -1;
2440        }
2441
2442        if (n > m) {
2443            // swap the two strings to consume less memory
2444            final CharSequence tmp = s;
2445            s = t;
2446            t = tmp;
2447            n = m;
2448            m = t.length();
2449        }
2450
2451        int[] p = new int[n + 1]; // 'previous' cost array, horizontally
2452        int[] d = new int[n + 1]; // cost array, horizontally
2453        int[] tmp; // placeholder to assist in swapping p and d
2454
2455        // fill in starting table values
2456        final int boundary = Math.min(n, threshold) + 1;
2457        for (int i = 0; i < boundary; i++) {
2458            p[i] = i;
2459        }
2460        // these fills ensure that the value above the rightmost entry of our
2461        // stripe will be ignored in following loop iterations
2462        Arrays.fill(p, boundary, p.length, Integer.MAX_VALUE);
2463        Arrays.fill(d, Integer.MAX_VALUE);
2464
2465        // iterates through t
2466        for (int j = 1; j <= m; j++) {
2467            final char jOfT = t.charAt(j - 1); // jth character of t
2468            d[0] = j;
2469
2470            // compute stripe indices, constrain to array size
2471            final int min = Math.max(1, j - threshold);
2472            final int max = j > Integer.MAX_VALUE - threshold ? n : Math.min(n, j + threshold);
2473
2474            // the stripe may lead off of the table if s and t are of different sizes
2475            if (min > max) {
2476                return -1;
2477            }
2478
2479            // ignore entry left of leftmost
2480            if (min > 1) {
2481                d[min - 1] = Integer.MAX_VALUE;
2482            }
2483
2484            // iterates through [min, max] in s
2485            for (int i = min; i <= max; i++) {
2486                if (s.charAt(i - 1) == jOfT) {
2487                    // diagonally left and up
2488                    d[i] = p[i - 1];
2489                } else {
2490                    // 1 + minimum of cell to the left, to the top, diagonally left and up
2491                    d[i] = 1 + Math.min(Math.min(d[i - 1], p[i]), p[i - 1]);
2492                }
2493            }
2494
2495            // copy current distance counts to 'previous row' distance counts
2496            tmp = p;
2497            p = d;
2498            d = tmp;
2499        }
2500
2501        // if p[n] is greater than the threshold, there's no guarantee on it being the correct
2502        // distance
2503        if (p[n] <= threshold) {
2504            return p[n];
2505        }
2506        return -1;
2507    }
2508
2509    /**
2510     * Finds the first index within a CharSequence, handling {@code null}.
2511     * This method uses {@link String#indexOf(String, int)} if possible.
2512     *
2513     * <p>A {@code null} CharSequence will return {@code -1}.</p>
2514     *
2515     * <pre>
2516     * StringUtils.indexOf(null, *)          = -1
2517     * StringUtils.indexOf(*, null)          = -1
2518     * StringUtils.indexOf("", "")           = 0
2519     * StringUtils.indexOf("", *)            = -1 (except when * = "")
2520     * StringUtils.indexOf("aabaabaa", "a")  = 0
2521     * StringUtils.indexOf("aabaabaa", "b")  = 2
2522     * StringUtils.indexOf("aabaabaa", "ab") = 1
2523     * StringUtils.indexOf("aabaabaa", "")   = 0
2524     * </pre>
2525     *
2526     * @param seq  the CharSequence to check, may be null
2527     * @param searchSeq  the CharSequence to find, may be null
2528     * @return the first index of the search CharSequence,
2529     *  -1 if no match or {@code null} string input
2530     * @since 2.0
2531     * @since 3.0 Changed signature from indexOf(String, String) to indexOf(CharSequence, CharSequence)
2532     * @deprecated Use {@link Strings#indexOf(CharSequence, CharSequence) Strings.CS.indexOf(CharSequence, CharSequence)}
2533     */
2534    @Deprecated
2535    public static int indexOf(final CharSequence seq, final CharSequence searchSeq) {
2536        return Strings.CS.indexOf(seq, searchSeq);
2537    }
2538
2539    /**
2540     * Finds the first index within a CharSequence, handling {@code null}.
2541     * This method uses {@link String#indexOf(String, int)} if possible.
2542     *
2543     * <p>A {@code null} CharSequence will return {@code -1}.
2544     * A negative start position is treated as zero.
2545     * An empty ("") search CharSequence always matches.
2546     * A start position greater than the string length only matches
2547     * an empty search CharSequence.</p>
2548     *
2549     * <pre>
2550     * StringUtils.indexOf(null, *, *)          = -1
2551     * StringUtils.indexOf(*, null, *)          = -1
2552     * StringUtils.indexOf("", "", 0)           = 0
2553     * StringUtils.indexOf("", *, 0)            = -1 (except when * = "")
2554     * StringUtils.indexOf("aabaabaa", "a", 0)  = 0
2555     * StringUtils.indexOf("aabaabaa", "b", 0)  = 2
2556     * StringUtils.indexOf("aabaabaa", "ab", 0) = 1
2557     * StringUtils.indexOf("aabaabaa", "b", 3)  = 5
2558     * StringUtils.indexOf("aabaabaa", "b", 9)  = -1
2559     * StringUtils.indexOf("aabaabaa", "b", -1) = 2
2560     * StringUtils.indexOf("aabaabaa", "", 2)   = 2
2561     * StringUtils.indexOf("abc", "", 9)        = 3
2562     * </pre>
2563     *
2564     * @param seq  the CharSequence to check, may be null
2565     * @param searchSeq  the CharSequence to find, may be null
2566     * @param startPos  the start position, negative treated as zero
2567     * @return the first index of the search CharSequence (always &ge; startPos),
2568     *  -1 if no match or {@code null} string input
2569     * @since 2.0
2570     * @since 3.0 Changed signature from indexOf(String, String, int) to indexOf(CharSequence, CharSequence, int)
2571     * @deprecated Use {@link Strings#indexOf(CharSequence, CharSequence, int) Strings.CS.indexOf(CharSequence, CharSequence, int)}
2572     */
2573    @Deprecated
2574    public static int indexOf(final CharSequence seq, final CharSequence searchSeq, final int startPos) {
2575        return Strings.CS.indexOf(seq, searchSeq, startPos);
2576    }
2577
2578    /**
2579     * Returns the index within {@code seq} of the first occurrence of
2580     * the specified character. If a character with value
2581     * {@code searchChar} occurs in the character sequence represented by
2582     * {@code seq} {@link CharSequence} object, then the index (in Unicode
2583     * code units) of the first such occurrence is returned. For
2584     * values of {@code searchChar} in the range from 0 to 0xFFFF
2585     * (inclusive), this is the smallest value <em>k</em> such that:
2586     * <blockquote><pre>
2587     * this.charAt(<em>k</em>) == searchChar
2588     * </pre></blockquote>
2589     * is true. For other values of {@code searchChar}, it is the
2590     * smallest value <em>k</em> such that:
2591     * <blockquote><pre>
2592     * this.codePointAt(<em>k</em>) == searchChar
2593     * </pre></blockquote>
2594     * is true. In either case, if no such character occurs in {@code seq},
2595     * then {@code INDEX_NOT_FOUND (-1)} is returned.
2596     *
2597     * <p>Furthermore, a {@code null} or empty ("") CharSequence will
2598     * return {@code INDEX_NOT_FOUND (-1)}.</p>
2599     *
2600     * <pre>
2601     * StringUtils.indexOf(null, *)         = -1
2602     * StringUtils.indexOf("", *)           = -1
2603     * StringUtils.indexOf("aabaabaa", 'a') = 0
2604     * StringUtils.indexOf("aabaabaa", 'b') = 2
2605     * StringUtils.indexOf("aaaaaaaa", 'Z') = -1
2606     * </pre>
2607     *
2608     * @param seq  the CharSequence to check, may be null
2609     * @param searchChar  the character to find
2610     * @return the first index of the search character,
2611     *  -1 if no match or {@code null} string input
2612     * @since 2.0
2613     * @since 3.0 Changed signature from indexOf(String, int) to indexOf(CharSequence, int)
2614     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@link String}
2615     */
2616    public static int indexOf(final CharSequence seq, final int searchChar) {
2617        if (isEmpty(seq)) {
2618            return INDEX_NOT_FOUND;
2619        }
2620        return CharSequenceUtils.indexOf(seq, searchChar, 0);
2621    }
2622
2623    /**
2624     * Returns the index within {@code seq} of the first occurrence of the
2625     * specified character, starting the search at the specified index.
2626     * <p>
2627     * If a character with value {@code searchChar} occurs in the
2628     * character sequence represented by the {@code seq} {@link CharSequence}
2629     * object at an index no smaller than {@code startPos}, then
2630     * the index of the first such occurrence is returned. For values
2631     * of {@code searchChar} in the range from 0 to 0xFFFF (inclusive),
2632     * this is the smallest value <em>k</em> such that:
2633     * <blockquote><pre>
2634     * (this.charAt(<em>k</em>) == searchChar) &amp;&amp; (<em>k</em> &gt;= startPos)
2635     * </pre></blockquote>
2636     * is true. For other values of {@code searchChar}, it is the
2637     * smallest value <em>k</em> such that:
2638     * <blockquote><pre>
2639     * (this.codePointAt(<em>k</em>) == searchChar) &amp;&amp; (<em>k</em> &gt;= startPos)
2640     * </pre></blockquote>
2641     * is true. In either case, if no such character occurs in {@code seq}
2642     * at or after position {@code startPos}, then
2643     * {@code -1} is returned.
2644     *
2645     * <p>
2646     * There is no restriction on the value of {@code startPos}. If it
2647     * is negative, it has the same effect as if it were zero: this entire
2648     * string may be searched. If it is greater than the length of this
2649     * string, it has the same effect as if it were equal to the length of
2650     * this string: {@code (INDEX_NOT_FOUND) -1} is returned. Furthermore, a
2651     * {@code null} or empty ("") CharSequence will
2652     * return {@code (INDEX_NOT_FOUND) -1}.
2653     *
2654     * <p>All indices are specified in {@code char} values
2655     * (Unicode code units).
2656     *
2657     * <pre>
2658     * StringUtils.indexOf(null, *, *)          = -1
2659     * StringUtils.indexOf("", *, *)            = -1
2660     * StringUtils.indexOf("aabaabaa", 'b', 0)  = 2
2661     * StringUtils.indexOf("aabaabaa", 'b', 3)  = 5
2662     * StringUtils.indexOf("aabaabaa", 'b', 9)  = -1
2663     * StringUtils.indexOf("aabaabaa", 'b', -1) = 2
2664     * </pre>
2665     *
2666     * @param seq  the CharSequence to check, may be null
2667     * @param searchChar  the character to find
2668     * @param startPos  the start position, negative treated as zero
2669     * @return the first index of the search character (always &ge; startPos),
2670     *  -1 if no match or {@code null} string input
2671     * @since 2.0
2672     * @since 3.0 Changed signature from indexOf(String, int, int) to indexOf(CharSequence, int, int)
2673     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@link String}
2674     */
2675    public static int indexOf(final CharSequence seq, final int searchChar, final int startPos) {
2676        if (isEmpty(seq)) {
2677            return INDEX_NOT_FOUND;
2678        }
2679        return CharSequenceUtils.indexOf(seq, searchChar, startPos);
2680    }
2681
2682    /**
2683     * Search a CharSequence to find the first index of any
2684     * character in the given set of characters.
2685     *
2686     * <p>A {@code null} String will return {@code -1}.
2687     * A {@code null} or zero length search array will return {@code -1}.</p>
2688     *
2689     * <pre>
2690     * StringUtils.indexOfAny(null, *)                  = -1
2691     * StringUtils.indexOfAny("", *)                    = -1
2692     * StringUtils.indexOfAny(*, null)                  = -1
2693     * StringUtils.indexOfAny(*, [])                    = -1
2694     * StringUtils.indexOfAny("zzabyycdxx", ['z', 'a']) = 0
2695     * StringUtils.indexOfAny("zzabyycdxx", ['b', 'y']) = 3
2696     * StringUtils.indexOfAny("aba", ['z'])             = -1
2697     * </pre>
2698     *
2699     * @param cs  the CharSequence to check, may be null
2700     * @param searchChars  the chars to search for, may be null
2701     * @return the index of any of the chars, -1 if no match or null input
2702     * @since 2.0
2703     * @since 3.0 Changed signature from indexOfAny(String, char[]) to indexOfAny(CharSequence, char...)
2704     */
2705    public static int indexOfAny(final CharSequence cs, final char... searchChars) {
2706        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
2707            return INDEX_NOT_FOUND;
2708        }
2709        final int csLen = cs.length();
2710        final int csLast = csLen - 1;
2711        final int searchLen = searchChars.length;
2712        final int searchLast = searchLen - 1;
2713        for (int i = 0; i < csLen; i++) {
2714            final char ch = cs.charAt(i);
2715            for (int j = 0; j < searchLen; j++) {
2716                if (searchChars[j] == ch) {
2717                    // ch is a supplementary character
2718                    if (i >= csLast || j >= searchLast || !Character.isHighSurrogate(ch) || searchChars[j + 1] == cs.charAt(i + 1)) {
2719                        return i;
2720                    }
2721                }
2722            }
2723        }
2724        return INDEX_NOT_FOUND;
2725    }
2726
2727    /**
2728     * Find the first index of any of a set of potential substrings.
2729     *
2730     * <p>A {@code null} CharSequence will return {@code -1}.
2731     * A {@code null} or zero length search array will return {@code -1}.
2732     * A {@code null} search array entry will be ignored, but a search
2733     * array containing "" will return {@code 0} if {@code str} is not
2734     * null. This method uses {@link String#indexOf(String)} if possible.</p>
2735     *
2736     * <pre>
2737     * StringUtils.indexOfAny(null, *)                      = -1
2738     * StringUtils.indexOfAny(*, null)                      = -1
2739     * StringUtils.indexOfAny(*, [])                        = -1
2740     * StringUtils.indexOfAny("zzabyycdxx", ["ab", "cd"])   = 2
2741     * StringUtils.indexOfAny("zzabyycdxx", ["cd", "ab"])   = 2
2742     * StringUtils.indexOfAny("zzabyycdxx", ["mn", "op"])   = -1
2743     * StringUtils.indexOfAny("zzabyycdxx", ["zab", "aby"]) = 1
2744     * StringUtils.indexOfAny("zzabyycdxx", [""])           = 0
2745     * StringUtils.indexOfAny("", [""])                     = 0
2746     * StringUtils.indexOfAny("", ["a"])                    = -1
2747     * </pre>
2748     *
2749     * @param str  the CharSequence to check, may be null
2750     * @param searchStrs  the CharSequences to search for, may be null
2751     * @return the first index of any of the searchStrs in str, -1 if no match
2752     * @since 3.0 Changed signature from indexOfAny(String, String[]) to indexOfAny(CharSequence, CharSequence...)
2753     */
2754    public static int indexOfAny(final CharSequence str, final CharSequence... searchStrs) {
2755        if (str == null || searchStrs == null) {
2756            return INDEX_NOT_FOUND;
2757        }
2758
2759        // String's can't have a MAX_VALUEth index.
2760        int ret = Integer.MAX_VALUE;
2761
2762        int tmp;
2763        for (final CharSequence search : searchStrs) {
2764            if (search == null) {
2765                continue;
2766            }
2767            tmp = CharSequenceUtils.indexOf(str, search, 0);
2768            if (tmp == INDEX_NOT_FOUND) {
2769                continue;
2770            }
2771
2772            if (tmp < ret) {
2773                ret = tmp;
2774            }
2775        }
2776
2777        return ret == Integer.MAX_VALUE ? INDEX_NOT_FOUND : ret;
2778    }
2779
2780    /**
2781     * Search a CharSequence to find the first index of any
2782     * character in the given set of characters.
2783     *
2784     * <p>A {@code null} String will return {@code -1}.
2785     * A {@code null} search string will return {@code -1}.</p>
2786     *
2787     * <pre>
2788     * StringUtils.indexOfAny(null, *)            = -1
2789     * StringUtils.indexOfAny("", *)              = -1
2790     * StringUtils.indexOfAny(*, null)            = -1
2791     * StringUtils.indexOfAny(*, "")              = -1
2792     * StringUtils.indexOfAny("zzabyycdxx", "za") = 0
2793     * StringUtils.indexOfAny("zzabyycdxx", "by") = 3
2794     * StringUtils.indexOfAny("aba", "z")         = -1
2795     * </pre>
2796     *
2797     * @param cs  the CharSequence to check, may be null
2798     * @param searchChars  the chars to search for, may be null
2799     * @return the index of any of the chars, -1 if no match or null input
2800     * @since 2.0
2801     * @since 3.0 Changed signature from indexOfAny(String, String) to indexOfAny(CharSequence, String)
2802     */
2803    public static int indexOfAny(final CharSequence cs, final String searchChars) {
2804        if (isEmpty(cs) || isEmpty(searchChars)) {
2805            return INDEX_NOT_FOUND;
2806        }
2807        return indexOfAny(cs, searchChars.toCharArray());
2808    }
2809
2810    /**
2811     * Searches a CharSequence to find the first index of any
2812     * character not in the given set of characters, i.e.,
2813     * find index i of first char in cs such that (cs.codePointAt(i) ∉ { x ∈ codepoints(searchChars) })
2814     *
2815     * <p>A {@code null} CharSequence will return {@code -1}.
2816     * A {@code null} or zero length search array will return {@code -1}.</p>
2817     *
2818     * <pre>
2819     * StringUtils.indexOfAnyBut(null, *)                              = -1
2820     * StringUtils.indexOfAnyBut("", *)                                = -1
2821     * StringUtils.indexOfAnyBut(*, null)                              = -1
2822     * StringUtils.indexOfAnyBut(*, [])                                = -1
2823     * StringUtils.indexOfAnyBut("zzabyycdxx", new char[] {'z', 'a'} ) = 3
2824     * StringUtils.indexOfAnyBut("aba", new char[] {'z'} )             = 0
2825     * StringUtils.indexOfAnyBut("aba", new char[] {'a', 'b'} )        = -1
2826
2827     * </pre>
2828     *
2829     * @param cs  the CharSequence to check, may be null
2830     * @param searchChars  the chars to search for, may be null
2831     * @return the index of any of the chars, -1 if no match or null input
2832     * @since 2.0
2833     * @since 3.0 Changed signature from indexOfAnyBut(String, char[]) to indexOfAnyBut(CharSequence, char...)
2834     */
2835    public static int indexOfAnyBut(final CharSequence cs, final char... searchChars) {
2836        if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
2837            return INDEX_NOT_FOUND;
2838        }
2839        return indexOfAnyBut(cs, CharBuffer.wrap(searchChars));
2840    }
2841
2842    /**
2843     * Search a CharSequence to find the first index of any
2844     * character not in the given set of characters, i.e.,
2845     * find index i of first char in seq such that (seq.codePointAt(i) ∉ { x ∈ codepoints(searchChars) })
2846     *
2847     * <p>A {@code null} CharSequence will return {@code -1}.
2848     * A {@code null} or empty search string will return {@code -1}.</p>
2849     *
2850     * <pre>
2851     * StringUtils.indexOfAnyBut(null, *)            = -1
2852     * StringUtils.indexOfAnyBut("", *)              = -1
2853     * StringUtils.indexOfAnyBut(*, null)            = -1
2854     * StringUtils.indexOfAnyBut(*, "")              = -1
2855     * StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
2856     * StringUtils.indexOfAnyBut("zzabyycdxx", "")   = -1
2857     * StringUtils.indexOfAnyBut("aba", "ab")        = -1
2858     * </pre>
2859     *
2860     * @param seq  the CharSequence to check, may be null
2861     * @param searchChars  the chars to search for, may be null
2862     * @return the index of any of the chars, -1 if no match or null input
2863     * @since 2.0
2864     * @since 3.0 Changed signature from indexOfAnyBut(String, String) to indexOfAnyBut(CharSequence, CharSequence)
2865     */
2866    public static int indexOfAnyBut(final CharSequence seq, final CharSequence searchChars) {
2867        if (isEmpty(seq) || isEmpty(searchChars)) {
2868            return INDEX_NOT_FOUND;
2869        }
2870        final Set<Integer> searchSetCodePoints = searchChars.codePoints()
2871                .boxed().collect(Collectors.toSet());
2872        // advance character index from one interpreted codepoint to the next
2873        for (int curSeqCharIdx = 0; curSeqCharIdx < seq.length();) {
2874            final int curSeqCodePoint = Character.codePointAt(seq, curSeqCharIdx);
2875            if (!searchSetCodePoints.contains(curSeqCodePoint)) {
2876                return curSeqCharIdx;
2877            }
2878            curSeqCharIdx += Character.charCount(curSeqCodePoint); // skip indices to paired low-surrogates
2879        }
2880        return INDEX_NOT_FOUND;
2881    }
2882
2883    /**
2884     * Compares all CharSequences in an array and returns the index at which the
2885     * CharSequences begin to differ.
2886     *
2887     * <p>For example,
2888     * {@code indexOfDifference(new String[] {"i am a machine", "i am a robot"}) -> 7}</p>
2889     *
2890     * <pre>
2891     * StringUtils.indexOfDifference(null)                             = -1
2892     * StringUtils.indexOfDifference(new String[] {})                  = -1
2893     * StringUtils.indexOfDifference(new String[] {"abc"})             = -1
2894     * StringUtils.indexOfDifference(new String[] {null, null})        = -1
2895     * StringUtils.indexOfDifference(new String[] {"", ""})            = -1
2896     * StringUtils.indexOfDifference(new String[] {"", null})          = 0
2897     * StringUtils.indexOfDifference(new String[] {"abc", null, null}) = 0
2898     * StringUtils.indexOfDifference(new String[] {null, null, "abc"}) = 0
2899     * StringUtils.indexOfDifference(new String[] {"", "abc"})         = 0
2900     * StringUtils.indexOfDifference(new String[] {"abc", ""})         = 0
2901     * StringUtils.indexOfDifference(new String[] {"abc", "abc"})      = -1
2902     * StringUtils.indexOfDifference(new String[] {"abc", "a"})        = 1
2903     * StringUtils.indexOfDifference(new String[] {"ab", "abxyz"})     = 2
2904     * StringUtils.indexOfDifference(new String[] {"abcde", "abxyz"})  = 2
2905     * StringUtils.indexOfDifference(new String[] {"abcde", "xyz"})    = 0
2906     * StringUtils.indexOfDifference(new String[] {"xyz", "abcde"})    = 0
2907     * StringUtils.indexOfDifference(new String[] {"i am a machine", "i am a robot"}) = 7
2908     * </pre>
2909     *
2910     * @param css  array of CharSequences, entries may be null
2911     * @return the index where the strings begin to differ; -1 if they are all equal
2912     * @since 2.4
2913     * @since 3.0 Changed signature from indexOfDifference(String...) to indexOfDifference(CharSequence...)
2914     */
2915    public static int indexOfDifference(final CharSequence... css) {
2916        if (ArrayUtils.getLength(css) <= 1) {
2917            return INDEX_NOT_FOUND;
2918        }
2919        boolean anyStringNull = false;
2920        boolean allStringsNull = true;
2921        final int arrayLen = css.length;
2922        int shortestStrLen = Integer.MAX_VALUE;
2923        int longestStrLen = 0;
2924
2925        // find the min and max string lengths; this avoids checking to make
2926        // sure we are not exceeding the length of the string each time through
2927        // the bottom loop.
2928        for (final CharSequence cs : css) {
2929            if (cs == null) {
2930                anyStringNull = true;
2931                shortestStrLen = 0;
2932            } else {
2933                allStringsNull = false;
2934                shortestStrLen = Math.min(cs.length(), shortestStrLen);
2935                longestStrLen = Math.max(cs.length(), longestStrLen);
2936            }
2937        }
2938
2939        // handle lists containing all nulls or all empty strings
2940        if (allStringsNull || longestStrLen == 0 && !anyStringNull) {
2941            return INDEX_NOT_FOUND;
2942        }
2943
2944        // handle lists containing some nulls or some empty strings
2945        if (shortestStrLen == 0) {
2946            return 0;
2947        }
2948
2949        // find the position with the first difference across all strings
2950        int firstDiff = -1;
2951        for (int stringPos = 0; stringPos < shortestStrLen; stringPos++) {
2952            final char comparisonChar = css[0].charAt(stringPos);
2953            for (int arrayPos = 1; arrayPos < arrayLen; arrayPos++) {
2954                if (css[arrayPos].charAt(stringPos) != comparisonChar) {
2955                    firstDiff = stringPos;
2956                    break;
2957                }
2958            }
2959            if (firstDiff != -1) {
2960                break;
2961            }
2962        }
2963
2964        if (firstDiff == -1 && shortestStrLen != longestStrLen) {
2965            // we compared all of the characters up to the length of the
2966            // shortest string and didn't find a match, but the string lengths
2967            // vary, so return the length of the shortest string.
2968            return shortestStrLen;
2969        }
2970        return firstDiff;
2971    }
2972
2973    /**
2974     * Compares two CharSequences, and returns the index at which the
2975     * CharSequences begin to differ.
2976     *
2977     * <p>For example,
2978     * {@code indexOfDifference("i am a machine", "i am a robot") -> 7}</p>
2979     *
2980     * <pre>
2981     * StringUtils.indexOfDifference(null, null)       = -1
2982     * StringUtils.indexOfDifference("", "")           = -1
2983     * StringUtils.indexOfDifference("", "abc")        = 0
2984     * StringUtils.indexOfDifference("abc", "")        = 0
2985     * StringUtils.indexOfDifference("abc", "abc")     = -1
2986     * StringUtils.indexOfDifference("ab", "abxyz")    = 2
2987     * StringUtils.indexOfDifference("abcde", "abxyz") = 2
2988     * StringUtils.indexOfDifference("abcde", "xyz")   = 0
2989     * </pre>
2990     *
2991     * @param cs1  the first CharSequence, may be null
2992     * @param cs2  the second CharSequence, may be null
2993     * @return the index where cs1 and cs2 begin to differ; -1 if they are equal
2994     * @since 2.0
2995     * @since 3.0 Changed signature from indexOfDifference(String, String) to
2996     * indexOfDifference(CharSequence, CharSequence)
2997     */
2998    public static int indexOfDifference(final CharSequence cs1, final CharSequence cs2) {
2999        if (cs1 == cs2) {
3000            return INDEX_NOT_FOUND;
3001        }
3002        if (cs1 == null || cs2 == null) {
3003            return 0;
3004        }
3005        int i;
3006        for (i = 0; i < cs1.length() && i < cs2.length(); ++i) {
3007            if (cs1.charAt(i) != cs2.charAt(i)) {
3008                break;
3009            }
3010        }
3011        if (i < cs2.length() || i < cs1.length()) {
3012            return i;
3013        }
3014        return INDEX_NOT_FOUND;
3015    }
3016
3017    /**
3018     * Case in-sensitive find of the first index within a CharSequence.
3019     *
3020     * <p>A {@code null} CharSequence will return {@code -1}.
3021     * A negative start position is treated as zero.
3022     * An empty ("") search CharSequence always matches.
3023     * A start position greater than the string length only matches
3024     * an empty search CharSequence.</p>
3025     *
3026     * <pre>
3027     * StringUtils.indexOfIgnoreCase(null, *)          = -1
3028     * StringUtils.indexOfIgnoreCase(*, null)          = -1
3029     * StringUtils.indexOfIgnoreCase("", "")           = 0
3030     * StringUtils.indexOfIgnoreCase(" ", " ")         = 0
3031     * StringUtils.indexOfIgnoreCase("aabaabaa", "a")  = 0
3032     * StringUtils.indexOfIgnoreCase("aabaabaa", "b")  = 2
3033     * StringUtils.indexOfIgnoreCase("aabaabaa", "ab") = 1
3034     * </pre>
3035     *
3036     * @param str  the CharSequence to check, may be null
3037     * @param searchStr  the CharSequence to find, may be null
3038     * @return the first index of the search CharSequence,
3039     *  -1 if no match or {@code null} string input
3040     * @since 2.5
3041     * @since 3.0 Changed signature from indexOfIgnoreCase(String, String) to indexOfIgnoreCase(CharSequence, CharSequence)
3042     * @deprecated Use {@link Strings#indexOf(CharSequence, CharSequence) Strings.CI.indexOf(CharSequence, CharSequence)}
3043     */
3044    @Deprecated
3045    public static int indexOfIgnoreCase(final CharSequence str, final CharSequence searchStr) {
3046        return Strings.CI.indexOf(str, searchStr);
3047    }
3048
3049    /**
3050     * Case in-sensitive find of the first index within a CharSequence
3051     * from the specified position.
3052     *
3053     * <p>A {@code null} CharSequence will return {@code -1}.
3054     * A negative start position is treated as zero.
3055     * An empty ("") search CharSequence always matches.
3056     * A start position greater than the string length only matches
3057     * an empty search CharSequence.</p>
3058     *
3059     * <pre>
3060     * StringUtils.indexOfIgnoreCase(null, *, *)          = -1
3061     * StringUtils.indexOfIgnoreCase(*, null, *)          = -1
3062     * StringUtils.indexOfIgnoreCase("", "", 0)           = 0
3063     * StringUtils.indexOfIgnoreCase("aabaabaa", "A", 0)  = 0
3064     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 0)  = 2
3065     * StringUtils.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
3066     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 3)  = 5
3067     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", 9)  = -1
3068     * StringUtils.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
3069     * StringUtils.indexOfIgnoreCase("aabaabaa", "", 2)   = 2
3070     * StringUtils.indexOfIgnoreCase("abc", "", 9)        = -1
3071     * </pre>
3072     *
3073     * @param str  the CharSequence to check, may be null
3074     * @param searchStr  the CharSequence to find, may be null
3075     * @param startPos  the start position, negative treated as zero
3076     * @return the first index of the search CharSequence (always &ge; startPos),
3077     *  -1 if no match or {@code null} string input
3078     * @since 2.5
3079     * @since 3.0 Changed signature from indexOfIgnoreCase(String, String, int) to indexOfIgnoreCase(CharSequence, CharSequence, int)
3080     * @deprecated Use {@link Strings#indexOf(CharSequence, CharSequence, int) Strings.CI.indexOf(CharSequence, CharSequence, int)}
3081     */
3082    @Deprecated
3083    public static int indexOfIgnoreCase(final CharSequence str, final CharSequence searchStr, final int startPos) {
3084        return Strings.CI.indexOf(str, searchStr, startPos);
3085    }
3086
3087    /**
3088     * Tests if all of the CharSequences are empty (""), null or whitespace only.
3089     *
3090     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3091     *
3092     * <pre>
3093     * StringUtils.isAllBlank(null)             = true
3094     * StringUtils.isAllBlank(null, "foo")      = false
3095     * StringUtils.isAllBlank(null, null)       = true
3096     * StringUtils.isAllBlank("", "bar")        = false
3097     * StringUtils.isAllBlank("bob", "")        = false
3098     * StringUtils.isAllBlank("  bob  ", null)  = false
3099     * StringUtils.isAllBlank(" ", "bar")       = false
3100     * StringUtils.isAllBlank("foo", "bar")     = false
3101     * StringUtils.isAllBlank(new String[] {})  = true
3102     * </pre>
3103     *
3104     * @param css  the CharSequences to check, may be null or empty
3105     * @return {@code true} if all of the CharSequences are empty or null or whitespace only
3106     * @since 3.6
3107     */
3108    public static boolean isAllBlank(final CharSequence... css) {
3109        if (ArrayUtils.isEmpty(css)) {
3110            return true;
3111        }
3112        for (final CharSequence cs : css) {
3113            if (isNotBlank(cs)) {
3114               return false;
3115            }
3116        }
3117        return true;
3118    }
3119
3120    /**
3121     * Tests if all of the CharSequences are empty ("") or null.
3122     *
3123     * <pre>
3124     * StringUtils.isAllEmpty(null)             = true
3125     * StringUtils.isAllEmpty(null, "")         = true
3126     * StringUtils.isAllEmpty(new String[] {})  = true
3127     * StringUtils.isAllEmpty(null, "foo")      = false
3128     * StringUtils.isAllEmpty("", "bar")        = false
3129     * StringUtils.isAllEmpty("bob", "")        = false
3130     * StringUtils.isAllEmpty("  bob  ", null)  = false
3131     * StringUtils.isAllEmpty(" ", "bar")       = false
3132     * StringUtils.isAllEmpty("foo", "bar")     = false
3133     * </pre>
3134     *
3135     * @param css  the CharSequences to check, may be null or empty
3136     * @return {@code true} if all of the CharSequences are empty or null
3137     * @since 3.6
3138     */
3139    public static boolean isAllEmpty(final CharSequence... css) {
3140        if (ArrayUtils.isEmpty(css)) {
3141            return true;
3142        }
3143        for (final CharSequence cs : css) {
3144            if (isNotEmpty(cs)) {
3145                return false;
3146            }
3147        }
3148        return true;
3149    }
3150
3151    /**
3152     * Tests if the CharSequence contains only lowercase characters.
3153     *
3154     * <p>{@code null} will return {@code false}.
3155     * An empty CharSequence (length()=0) will return {@code false}.</p>
3156     *
3157     * <pre>
3158     * StringUtils.isAllLowerCase(null)   = false
3159     * StringUtils.isAllLowerCase("")     = false
3160     * StringUtils.isAllLowerCase("  ")   = false
3161     * StringUtils.isAllLowerCase("abc")  = true
3162     * StringUtils.isAllLowerCase("abC")  = false
3163     * StringUtils.isAllLowerCase("ab c") = false
3164     * StringUtils.isAllLowerCase("ab1c") = false
3165     * StringUtils.isAllLowerCase("ab/c") = false
3166     * </pre>
3167     *
3168     * @param cs  the CharSequence to check, may be null
3169     * @return {@code true} if only contains lowercase characters, and is non-null
3170     * @since 2.5
3171     * @since 3.0 Changed signature from isAllLowerCase(String) to isAllLowerCase(CharSequence)
3172     */
3173    public static boolean isAllLowerCase(final CharSequence cs) {
3174        if (isEmpty(cs)) {
3175            return false;
3176        }
3177        final int sz = cs.length();
3178        for (int i = 0; i < sz; i++) {
3179            if (!Character.isLowerCase(cs.charAt(i))) {
3180                return false;
3181            }
3182        }
3183        return true;
3184    }
3185
3186    /**
3187     * Tests if the CharSequence contains only uppercase characters.
3188     *
3189     * <p>{@code null} will return {@code false}.
3190     * An empty String (length()=0) will return {@code false}.</p>
3191     *
3192     * <pre>
3193     * StringUtils.isAllUpperCase(null)   = false
3194     * StringUtils.isAllUpperCase("")     = false
3195     * StringUtils.isAllUpperCase("  ")   = false
3196     * StringUtils.isAllUpperCase("ABC")  = true
3197     * StringUtils.isAllUpperCase("aBC")  = false
3198     * StringUtils.isAllUpperCase("A C")  = false
3199     * StringUtils.isAllUpperCase("A1C")  = false
3200     * StringUtils.isAllUpperCase("A/C")  = false
3201     * </pre>
3202     *
3203     * @param cs the CharSequence to check, may be null
3204     * @return {@code true} if only contains uppercase characters, and is non-null
3205     * @since 2.5
3206     * @since 3.0 Changed signature from isAllUpperCase(String) to isAllUpperCase(CharSequence)
3207     */
3208    public static boolean isAllUpperCase(final CharSequence cs) {
3209        if (isEmpty(cs)) {
3210            return false;
3211        }
3212        final int sz = cs.length();
3213        for (int i = 0; i < sz; i++) {
3214            if (!Character.isUpperCase(cs.charAt(i))) {
3215                return false;
3216            }
3217        }
3218        return true;
3219    }
3220
3221    /**
3222     * Tests if the CharSequence contains only Unicode letters.
3223     *
3224     * <p>{@code null} will return {@code false}.
3225     * An empty CharSequence (length()=0) will return {@code false}.</p>
3226     *
3227     * <pre>
3228     * StringUtils.isAlpha(null)   = false
3229     * StringUtils.isAlpha("")     = false
3230     * StringUtils.isAlpha("  ")   = false
3231     * StringUtils.isAlpha("abc")  = true
3232     * StringUtils.isAlpha("ab2c") = false
3233     * StringUtils.isAlpha("ab-c") = false
3234     * </pre>
3235     *
3236     * @param cs  the CharSequence to check, may be null
3237     * @return {@code true} if only contains letters, and is non-null
3238     * @since 3.0 Changed signature from isAlpha(String) to isAlpha(CharSequence)
3239     * @since 3.0 Changed "" to return false and not true
3240     */
3241    public static boolean isAlpha(final CharSequence cs) {
3242        if (isEmpty(cs)) {
3243            return false;
3244        }
3245        final int sz = cs.length();
3246        for (int i = 0; i < sz; i++) {
3247            if (!Character.isLetter(cs.charAt(i))) {
3248                return false;
3249            }
3250        }
3251        return true;
3252    }
3253
3254    /**
3255     * Tests if the CharSequence contains only Unicode letters or digits.
3256     *
3257     * <p>{@code null} will return {@code false}.
3258     * An empty CharSequence (length()=0) will return {@code false}.</p>
3259     *
3260     * <pre>
3261     * StringUtils.isAlphanumeric(null)   = false
3262     * StringUtils.isAlphanumeric("")     = false
3263     * StringUtils.isAlphanumeric("  ")   = false
3264     * StringUtils.isAlphanumeric("abc")  = true
3265     * StringUtils.isAlphanumeric("ab c") = false
3266     * StringUtils.isAlphanumeric("ab2c") = true
3267     * StringUtils.isAlphanumeric("ab-c") = false
3268     * </pre>
3269     *
3270     * @param cs  the CharSequence to check, may be null
3271     * @return {@code true} if only contains letters or digits,
3272     *  and is non-null
3273     * @since 3.0 Changed signature from isAlphanumeric(String) to isAlphanumeric(CharSequence)
3274     * @since 3.0 Changed "" to return false and not true
3275     */
3276    public static boolean isAlphanumeric(final CharSequence cs) {
3277        if (isEmpty(cs)) {
3278            return false;
3279        }
3280        final int sz = cs.length();
3281        for (int i = 0; i < sz; i++) {
3282            if (!Character.isLetterOrDigit(cs.charAt(i))) {
3283                return false;
3284            }
3285        }
3286        return true;
3287    }
3288
3289    /**
3290     * Tests if the CharSequence contains only Unicode letters, digits
3291     * or space ({@code ' '}).
3292     *
3293     * <p>{@code null} will return {@code false}.
3294     * An empty CharSequence (length()=0) will return {@code true}.</p>
3295     *
3296     * <pre>
3297     * StringUtils.isAlphanumericSpace(null)   = false
3298     * StringUtils.isAlphanumericSpace("")     = true
3299     * StringUtils.isAlphanumericSpace("  ")   = true
3300     * StringUtils.isAlphanumericSpace("abc")  = true
3301     * StringUtils.isAlphanumericSpace("ab c") = true
3302     * StringUtils.isAlphanumericSpace("ab2c") = true
3303     * StringUtils.isAlphanumericSpace("ab-c") = false
3304     * </pre>
3305     *
3306     * @param cs  the CharSequence to check, may be null
3307     * @return {@code true} if only contains letters, digits or space,
3308     *  and is non-null
3309     * @since 3.0 Changed signature from isAlphanumericSpace(String) to isAlphanumericSpace(CharSequence)
3310     */
3311    public static boolean isAlphanumericSpace(final CharSequence cs) {
3312        if (cs == null) {
3313            return false;
3314        }
3315        final int sz = cs.length();
3316        for (int i = 0; i < sz; i++) {
3317            final char nowChar = cs.charAt(i);
3318            if (nowChar != ' ' && !Character.isLetterOrDigit(nowChar)) {
3319                return false;
3320            }
3321        }
3322        return true;
3323    }
3324
3325    /**
3326     * Tests if the CharSequence contains only Unicode letters and
3327     * space (' ').
3328     *
3329     * <p>{@code null} will return {@code false}
3330     * An empty CharSequence (length()=0) will return {@code true}.</p>
3331     *
3332     * <pre>
3333     * StringUtils.isAlphaSpace(null)   = false
3334     * StringUtils.isAlphaSpace("")     = true
3335     * StringUtils.isAlphaSpace("  ")   = true
3336     * StringUtils.isAlphaSpace("abc")  = true
3337     * StringUtils.isAlphaSpace("ab c") = true
3338     * StringUtils.isAlphaSpace("ab2c") = false
3339     * StringUtils.isAlphaSpace("ab-c") = false
3340     * </pre>
3341     *
3342     * @param cs  the CharSequence to check, may be null
3343     * @return {@code true} if only contains letters and space,
3344     *  and is non-null
3345     * @since 3.0 Changed signature from isAlphaSpace(String) to isAlphaSpace(CharSequence)
3346     */
3347    public static boolean isAlphaSpace(final CharSequence cs) {
3348        if (cs == null) {
3349            return false;
3350        }
3351        final int sz = cs.length();
3352        for (int i = 0; i < sz; i++) {
3353            final char nowChar = cs.charAt(i);
3354            if (nowChar != ' ' && !Character.isLetter(nowChar)) {
3355                return false;
3356            }
3357        }
3358        return true;
3359    }
3360
3361    /**
3362     * Tests if any of the CharSequences are {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or {@code null}).
3363     *
3364     * <p>
3365     * Whitespace is defined by {@link Character#isWhitespace(char)}.
3366     * </p>
3367     *
3368     * <pre>
3369     * StringUtils.isAnyBlank((String) null)    = true
3370     * StringUtils.isAnyBlank((String[]) null)  = false
3371     * StringUtils.isAnyBlank(null, "foo")      = true
3372     * StringUtils.isAnyBlank(null, null)       = true
3373     * StringUtils.isAnyBlank("", "bar")        = true
3374     * StringUtils.isAnyBlank("bob", "")        = true
3375     * StringUtils.isAnyBlank("  bob  ", null)  = true
3376     * StringUtils.isAnyBlank(" ", "bar")       = true
3377     * StringUtils.isAnyBlank(new String[] {})  = false
3378     * StringUtils.isAnyBlank(new String[]{""}) = true
3379     * StringUtils.isAnyBlank("foo", "bar")     = false
3380     * </pre>
3381     *
3382     * @param css the CharSequences to check, may be null or empty
3383     * @return {@code true} if any of the CharSequences are {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or {@code null})
3384     * @see #isBlank(CharSequence)
3385     * @since 3.2
3386     */
3387    public static boolean isAnyBlank(final CharSequence... css) {
3388        if (ArrayUtils.isEmpty(css)) {
3389            return false;
3390        }
3391        for (final CharSequence cs : css) {
3392            if (isBlank(cs)) {
3393                return true;
3394            }
3395        }
3396        return false;
3397    }
3398
3399    /**
3400     * Tests if any of the CharSequences are empty ("") or null.
3401     *
3402     * <pre>
3403     * StringUtils.isAnyEmpty((String) null)    = true
3404     * StringUtils.isAnyEmpty((String[]) null)  = false
3405     * StringUtils.isAnyEmpty(null, "foo")      = true
3406     * StringUtils.isAnyEmpty("", "bar")        = true
3407     * StringUtils.isAnyEmpty("bob", "")        = true
3408     * StringUtils.isAnyEmpty("  bob  ", null)  = true
3409     * StringUtils.isAnyEmpty(" ", "bar")       = false
3410     * StringUtils.isAnyEmpty("foo", "bar")     = false
3411     * StringUtils.isAnyEmpty(new String[]{})   = false
3412     * StringUtils.isAnyEmpty(new String[]{""}) = true
3413     * </pre>
3414     *
3415     * @param css  the CharSequences to check, may be null or empty
3416     * @return {@code true} if any of the CharSequences are empty or null
3417     * @since 3.2
3418     */
3419    public static boolean isAnyEmpty(final CharSequence... css) {
3420        if (ArrayUtils.isEmpty(css)) {
3421            return false;
3422        }
3423        for (final CharSequence cs : css) {
3424            if (isEmpty(cs)) {
3425                return true;
3426            }
3427        }
3428        return false;
3429    }
3430
3431    /**
3432     * Tests if the CharSequence contains only ASCII printable characters.
3433     *
3434     * <p>{@code null} will return {@code false}.
3435     * An empty CharSequence (length()=0) will return {@code true}.</p>
3436     *
3437     * <pre>
3438     * StringUtils.isAsciiPrintable(null)     = false
3439     * StringUtils.isAsciiPrintable("")       = true
3440     * StringUtils.isAsciiPrintable(" ")      = true
3441     * StringUtils.isAsciiPrintable("Ceki")   = true
3442     * StringUtils.isAsciiPrintable("ab2c")   = true
3443     * StringUtils.isAsciiPrintable("!ab-c~") = true
3444     * StringUtils.isAsciiPrintable("\u0020") = true
3445     * StringUtils.isAsciiPrintable("\u0021") = true
3446     * StringUtils.isAsciiPrintable("\u007e") = true
3447     * StringUtils.isAsciiPrintable("\u007f") = false
3448     * StringUtils.isAsciiPrintable("Ceki G\u00fclc\u00fc") = false
3449     * </pre>
3450     *
3451     * @param cs the CharSequence to check, may be null
3452     * @return {@code true} if every character is in the range
3453     *  32 through 126
3454     * @since 2.1
3455     * @since 3.0 Changed signature from isAsciiPrintable(String) to isAsciiPrintable(CharSequence)
3456     */
3457    public static boolean isAsciiPrintable(final CharSequence cs) {
3458        if (cs == null) {
3459            return false;
3460        }
3461        final int sz = cs.length();
3462        for (int i = 0; i < sz; i++) {
3463            if (!CharUtils.isAsciiPrintable(cs.charAt(i))) {
3464                return false;
3465            }
3466        }
3467        return true;
3468    }
3469
3470    /**
3471     * Tests if a CharSequence is empty ({@code "")}, null, or contains only whitespace as defined by {@link Character#isWhitespace(char)}.
3472     *
3473     * <pre>
3474     * StringUtils.isBlank(null)      = true
3475     * StringUtils.isBlank("")        = true
3476     * StringUtils.isBlank(" ")       = true
3477     * StringUtils.isBlank("bob")     = false
3478     * StringUtils.isBlank("  bob  ") = false
3479     * </pre>
3480     *
3481     * @param cs the CharSequence to check, may be null
3482     * @return {@code true} if the CharSequence is null, empty or whitespace only
3483     * @since 2.0
3484     * @since 3.0 Changed signature from isBlank(String) to isBlank(CharSequence)
3485     */
3486    public static boolean isBlank(final CharSequence cs) {
3487        final int strLen = length(cs);
3488        if (strLen == 0) {
3489            return true;
3490        }
3491        for (int i = 0; i < strLen; i++) {
3492            if (!Character.isWhitespace(cs.charAt(i))) {
3493                return false;
3494            }
3495        }
3496        return true;
3497    }
3498
3499    /**
3500     * Tests if a CharSequence is empty ("") or null.
3501     *
3502     * <pre>
3503     * StringUtils.isEmpty(null)      = true
3504     * StringUtils.isEmpty("")        = true
3505     * StringUtils.isEmpty(" ")       = false
3506     * StringUtils.isEmpty("bob")     = false
3507     * StringUtils.isEmpty("  bob  ") = false
3508     * </pre>
3509     *
3510     * <p>NOTE: This method changed in Lang version 2.0.
3511     * It no longer trims the CharSequence.
3512     * That functionality is available in isBlank().</p>
3513     *
3514     * @param cs  the CharSequence to check, may be null
3515     * @return {@code true} if the CharSequence is empty or null
3516     * @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
3517     */
3518    public static boolean isEmpty(final CharSequence cs) {
3519        return cs == null || cs.length() == 0;
3520    }
3521
3522    /**
3523     * Tests if the CharSequence contains mixed casing of both uppercase and lowercase characters.
3524     *
3525     * <p>{@code null} will return {@code false}. An empty CharSequence ({@code length()=0}) will return
3526     * {@code false}.</p>
3527     *
3528     * <pre>
3529     * StringUtils.isMixedCase(null)    = false
3530     * StringUtils.isMixedCase("")      = false
3531     * StringUtils.isMixedCase(" ")     = false
3532     * StringUtils.isMixedCase("ABC")   = false
3533     * StringUtils.isMixedCase("abc")   = false
3534     * StringUtils.isMixedCase("aBc")   = true
3535     * StringUtils.isMixedCase("A c")   = true
3536     * StringUtils.isMixedCase("A1c")   = true
3537     * StringUtils.isMixedCase("a/C")   = true
3538     * StringUtils.isMixedCase("aC\t")  = true
3539     * </pre>
3540     *
3541     * @param cs the CharSequence to check, may be null
3542     * @return {@code true} if the CharSequence contains both uppercase and lowercase characters
3543     * @since 3.5
3544     */
3545    public static boolean isMixedCase(final CharSequence cs) {
3546        if (isEmpty(cs) || cs.length() == 1) {
3547            return false;
3548        }
3549        boolean containsUppercase = false;
3550        boolean containsLowercase = false;
3551        final int sz = cs.length();
3552        for (int i = 0; i < sz; i++) {
3553            final char nowChar = cs.charAt(i);
3554            if (Character.isUpperCase(nowChar)) {
3555                containsUppercase = true;
3556            } else if (Character.isLowerCase(nowChar)) {
3557                containsLowercase = true;
3558            }
3559            if (containsUppercase && containsLowercase) {
3560                return true;
3561            }
3562        }
3563        return false;
3564    }
3565
3566    /**
3567     * Tests if none of the CharSequences are empty (""), null or whitespace only.
3568     *
3569     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3570     *
3571     * <pre>
3572     * StringUtils.isNoneBlank((String) null)    = false
3573     * StringUtils.isNoneBlank((String[]) null)  = true
3574     * StringUtils.isNoneBlank(null, "foo")      = false
3575     * StringUtils.isNoneBlank(null, null)       = false
3576     * StringUtils.isNoneBlank("", "bar")        = false
3577     * StringUtils.isNoneBlank("bob", "")        = false
3578     * StringUtils.isNoneBlank("  bob  ", null)  = false
3579     * StringUtils.isNoneBlank(" ", "bar")       = false
3580     * StringUtils.isNoneBlank(new String[] {})  = true
3581     * StringUtils.isNoneBlank(new String[]{""}) = false
3582     * StringUtils.isNoneBlank("foo", "bar")     = true
3583     * </pre>
3584     *
3585     * @param css  the CharSequences to check, may be null or empty
3586     * @return {@code true} if none of the CharSequences are empty or null or whitespace only
3587     * @since 3.2
3588     */
3589    public static boolean isNoneBlank(final CharSequence... css) {
3590      return !isAnyBlank(css);
3591    }
3592
3593    /**
3594     * Tests if none of the CharSequences are empty ("") or null.
3595     *
3596     * <pre>
3597     * StringUtils.isNoneEmpty((String) null)    = false
3598     * StringUtils.isNoneEmpty((String[]) null)  = true
3599     * StringUtils.isNoneEmpty(null, "foo")      = false
3600     * StringUtils.isNoneEmpty("", "bar")        = false
3601     * StringUtils.isNoneEmpty("bob", "")        = false
3602     * StringUtils.isNoneEmpty("  bob  ", null)  = false
3603     * StringUtils.isNoneEmpty(new String[] {})  = true
3604     * StringUtils.isNoneEmpty(new String[]{""}) = false
3605     * StringUtils.isNoneEmpty(" ", "bar")       = true
3606     * StringUtils.isNoneEmpty("foo", "bar")     = true
3607     * </pre>
3608     *
3609     * @param css  the CharSequences to check, may be null or empty
3610     * @return {@code true} if none of the CharSequences are empty or null
3611     * @since 3.2
3612     */
3613    public static boolean isNoneEmpty(final CharSequence... css) {
3614      return !isAnyEmpty(css);
3615    }
3616
3617    /**
3618     * Tests if a CharSequence is not {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or {@code null}).
3619     *
3620     * <p>
3621     * Whitespace is defined by {@link Character#isWhitespace(char)}.
3622     * </p>
3623     *
3624     * <pre>
3625     * StringUtils.isNotBlank(null)      = false
3626     * StringUtils.isNotBlank("")        = false
3627     * StringUtils.isNotBlank(" ")       = false
3628     * StringUtils.isNotBlank("bob")     = true
3629     * StringUtils.isNotBlank("  bob  ") = true
3630     * </pre>
3631     *
3632     * @param cs the CharSequence to check, may be null
3633     * @return {@code true} if the CharSequence is not {@link #isBlank(CharSequence) blank} (whitespaces, empty ({@code ""}) or {@code null})
3634     * @see #isBlank(CharSequence)
3635     * @since 2.0
3636     * @since 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)
3637     */
3638    public static boolean isNotBlank(final CharSequence cs) {
3639        return !isBlank(cs);
3640    }
3641
3642    /**
3643     * Tests if a CharSequence is not empty ("") and not null.
3644     *
3645     * <pre>
3646     * StringUtils.isNotEmpty(null)      = false
3647     * StringUtils.isNotEmpty("")        = false
3648     * StringUtils.isNotEmpty(" ")       = true
3649     * StringUtils.isNotEmpty("bob")     = true
3650     * StringUtils.isNotEmpty("  bob  ") = true
3651     * </pre>
3652     *
3653     * @param cs  the CharSequence to check, may be null
3654     * @return {@code true} if the CharSequence is not empty and not null
3655     * @since 3.0 Changed signature from isNotEmpty(String) to isNotEmpty(CharSequence)
3656     */
3657    public static boolean isNotEmpty(final CharSequence cs) {
3658        return !isEmpty(cs);
3659    }
3660
3661    /**
3662     * Tests if the CharSequence contains only Unicode digits.
3663     * A decimal point is not a Unicode digit and returns false.
3664     *
3665     * <p>{@code null} will return {@code false}.
3666     * An empty CharSequence (length()=0) will return {@code false}.</p>
3667     *
3668     * <p>Note that the method does not allow for a leading sign, either positive or negative.
3669     * Also, if a String passes the numeric test, it may still generate a NumberFormatException
3670     * when parsed by Integer.parseInt or Long.parseLong, e.g. if the value is outside the range
3671     * for int or long respectively.</p>
3672     *
3673     * <pre>
3674     * StringUtils.isNumeric(null)   = false
3675     * StringUtils.isNumeric("")     = false
3676     * StringUtils.isNumeric("  ")   = false
3677     * StringUtils.isNumeric("123")  = true
3678     * StringUtils.isNumeric("\u0967\u0968\u0969")  = true
3679     * StringUtils.isNumeric("12 3") = false
3680     * StringUtils.isNumeric("ab2c") = false
3681     * StringUtils.isNumeric("12-3") = false
3682     * StringUtils.isNumeric("12.3") = false
3683     * StringUtils.isNumeric("-123") = false
3684     * StringUtils.isNumeric("+123") = false
3685     * </pre>
3686     *
3687     * @param cs  the CharSequence to check, may be null
3688     * @return {@code true} if only contains digits, and is non-null
3689     * @since 3.0 Changed signature from isNumeric(String) to isNumeric(CharSequence)
3690     * @since 3.0 Changed "" to return false and not true
3691     */
3692    public static boolean isNumeric(final CharSequence cs) {
3693        if (isEmpty(cs)) {
3694            return false;
3695        }
3696        final int sz = cs.length();
3697        for (int i = 0; i < sz; i++) {
3698            if (!Character.isDigit(cs.charAt(i))) {
3699                return false;
3700            }
3701        }
3702        return true;
3703    }
3704
3705    /**
3706     * Tests if the CharSequence contains only Unicode digits or space
3707     * ({@code ' '}).
3708     * A decimal point is not a Unicode digit and returns false.
3709     *
3710     * <p>{@code null} will return {@code false}.
3711     * An empty CharSequence (length()=0) will return {@code true}.</p>
3712     *
3713     * <pre>
3714     * StringUtils.isNumericSpace(null)   = false
3715     * StringUtils.isNumericSpace("")     = true
3716     * StringUtils.isNumericSpace("  ")   = true
3717     * StringUtils.isNumericSpace("123")  = true
3718     * StringUtils.isNumericSpace("12 3") = true
3719     * StringUtils.isNumericSpace("\u0967\u0968\u0969")   = true
3720     * StringUtils.isNumericSpace("\u0967\u0968 \u0969")  = true
3721     * StringUtils.isNumericSpace("ab2c") = false
3722     * StringUtils.isNumericSpace("12-3") = false
3723     * StringUtils.isNumericSpace("12.3") = false
3724     * </pre>
3725     *
3726     * @param cs  the CharSequence to check, may be null
3727     * @return {@code true} if only contains digits or space,
3728     *  and is non-null
3729     * @since 3.0 Changed signature from isNumericSpace(String) to isNumericSpace(CharSequence)
3730     */
3731    public static boolean isNumericSpace(final CharSequence cs) {
3732        if (cs == null) {
3733            return false;
3734        }
3735        final int sz = cs.length();
3736        for (int i = 0; i < sz; i++) {
3737            final char nowChar = cs.charAt(i);
3738            if (nowChar != ' ' && !Character.isDigit(nowChar)) {
3739                return false;
3740            }
3741        }
3742        return true;
3743    }
3744
3745    /**
3746     * Tests if the CharSequence contains only whitespace.
3747     *
3748     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
3749     *
3750     * <p>{@code null} will return {@code false}.
3751     * An empty CharSequence (length()=0) will return {@code true}.</p>
3752     *
3753     * <pre>
3754     * StringUtils.isWhitespace(null)   = false
3755     * StringUtils.isWhitespace("")     = true
3756     * StringUtils.isWhitespace("  ")   = true
3757     * StringUtils.isWhitespace("abc")  = false
3758     * StringUtils.isWhitespace("ab2c") = false
3759     * StringUtils.isWhitespace("ab-c") = false
3760     * </pre>
3761     *
3762     * @param cs  the CharSequence to check, may be null
3763     * @return {@code true} if only contains whitespace, and is non-null
3764     * @since 2.0
3765     * @since 3.0 Changed signature from isWhitespace(String) to isWhitespace(CharSequence)
3766     */
3767    public static boolean isWhitespace(final CharSequence cs) {
3768        if (cs == null) {
3769            return false;
3770        }
3771        final int sz = cs.length();
3772        for (int i = 0; i < sz; i++) {
3773            if (!Character.isWhitespace(cs.charAt(i))) {
3774                return false;
3775            }
3776        }
3777        return true;
3778    }
3779
3780    /**
3781     * Joins the elements of the provided array into a single String containing the provided list of elements.
3782     *
3783     * <p>
3784     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3785     * by empty strings.
3786     * </p>
3787     *
3788     * <pre>
3789     * StringUtils.join(null, *)             = null
3790     * StringUtils.join([], *)               = ""
3791     * StringUtils.join([null], *)           = ""
3792     * StringUtils.join([false, false], ';') = "false;false"
3793     * </pre>
3794     *
3795     * @param array
3796     *            the array of values to join together, may be null
3797     * @param delimiter
3798     *            the separator character to use
3799     * @return the joined String, {@code null} if null array input
3800     * @since 3.12.0
3801     */
3802    public static String join(final boolean[] array, final char delimiter) {
3803        if (array == null) {
3804            return null;
3805        }
3806        return join(array, delimiter, 0, array.length);
3807    }
3808
3809    /**
3810     * Joins the elements of the provided array into a single String containing the provided list of elements.
3811     *
3812     * <p>
3813     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3814     * by empty strings.
3815     * </p>
3816     *
3817     * <pre>
3818     * StringUtils.join(null, *)                  = null
3819     * StringUtils.join([], *)                    = ""
3820     * StringUtils.join([null], *)                = ""
3821     * StringUtils.join([true, false, true], ';') = "true;false;true"
3822     * </pre>
3823     *
3824     * @param array
3825     *            the array of values to join together, may be null
3826     * @param delimiter
3827     *            the separator character to use
3828     * @param startIndex
3829     *            the first index to start joining from. It is an error to pass in a start index past the end of the
3830     *            array
3831     * @param endIndex
3832     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
3833     *            the array
3834     * @return the joined String, {@code null} if null array input
3835     * @since 3.12.0
3836     */
3837    public static String join(final boolean[] array, final char delimiter, final int startIndex, final int endIndex) {
3838        if (array == null) {
3839            return null;
3840        }
3841        if (endIndex - startIndex <= 0) {
3842            return EMPTY;
3843        }
3844        final StringBuilder stringBuilder = new StringBuilder(array.length * 5 + array.length - 1);
3845        for (int i = startIndex; i < endIndex; i++) {
3846            stringBuilder
3847                    .append(array[i])
3848                    .append(delimiter);
3849        }
3850        return stringBuilder.substring(0, stringBuilder.length() - 1);
3851    }
3852
3853    /**
3854     * Joins the elements of the provided array into a single String containing the provided list of elements.
3855     *
3856     * <p>
3857     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3858     * by empty strings.
3859     * </p>
3860     *
3861     * <pre>
3862     * StringUtils.join(null, *)         = null
3863     * StringUtils.join([], *)           = ""
3864     * StringUtils.join([null], *)       = ""
3865     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3866     * StringUtils.join([1, 2, 3], null) = "123"
3867     * </pre>
3868     *
3869     * @param array
3870     *            the array of values to join together, may be null
3871     * @param delimiter
3872     *            the separator character to use
3873     * @return the joined String, {@code null} if null array input
3874     * @since 3.2
3875     */
3876    public static String join(final byte[] array, final char delimiter) {
3877        if (array == null) {
3878            return null;
3879        }
3880        return join(array, delimiter, 0, array.length);
3881    }
3882
3883    /**
3884     * Joins the elements of the provided array into a single String containing the provided list of elements.
3885     *
3886     * <p>
3887     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3888     * by empty strings.
3889     * </p>
3890     *
3891     * <pre>
3892     * StringUtils.join(null, *)         = null
3893     * StringUtils.join([], *)           = ""
3894     * StringUtils.join([null], *)       = ""
3895     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3896     * StringUtils.join([1, 2, 3], null) = "123"
3897     * </pre>
3898     *
3899     * @param array
3900     *            the array of values to join together, may be null
3901     * @param delimiter
3902     *            the separator character to use
3903     * @param startIndex
3904     *            the first index to start joining from. It is an error to pass in a start index past the end of the
3905     *            array
3906     * @param endIndex
3907     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
3908     *            the array
3909     * @return the joined String, {@code null} if null array input
3910     * @since 3.2
3911     */
3912    public static String join(final byte[] array, final char delimiter, final int startIndex, final int endIndex) {
3913        if (array == null) {
3914            return null;
3915        }
3916        if (endIndex - startIndex <= 0) {
3917            return EMPTY;
3918        }
3919        final StringBuilder stringBuilder = new StringBuilder();
3920        for (int i = startIndex; i < endIndex; i++) {
3921            stringBuilder
3922                    .append(array[i])
3923                    .append(delimiter);
3924        }
3925        return stringBuilder.substring(0, stringBuilder.length() - 1);
3926    }
3927
3928    /**
3929     * Joins the elements of the provided array into a single String containing the provided list of elements.
3930     *
3931     * <p>
3932     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3933     * by empty strings.
3934     * </p>
3935     *
3936     * <pre>
3937     * StringUtils.join(null, *)         = null
3938     * StringUtils.join([], *)           = ""
3939     * StringUtils.join([null], *)       = ""
3940     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3941     * StringUtils.join([1, 2, 3], null) = "123"
3942     * </pre>
3943     *
3944     * @param array
3945     *            the array of values to join together, may be null
3946     * @param delimiter
3947     *            the separator character to use
3948     * @return the joined String, {@code null} if null array input
3949     * @since 3.2
3950     */
3951    public static String join(final char[] array, final char delimiter) {
3952        if (array == null) {
3953            return null;
3954        }
3955        return join(array, delimiter, 0, array.length);
3956    }
3957
3958    /**
3959     * Joins the elements of the provided array into a single String containing the provided list of elements.
3960     *
3961     * <p>
3962     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
3963     * by empty strings.
3964     * </p>
3965     *
3966     * <pre>
3967     * StringUtils.join(null, *)         = null
3968     * StringUtils.join([], *)           = ""
3969     * StringUtils.join([null], *)       = ""
3970     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
3971     * StringUtils.join([1, 2, 3], null) = "123"
3972     * </pre>
3973     *
3974     * @param array
3975     *            the array of values to join together, may be null
3976     * @param delimiter
3977     *            the separator character to use
3978     * @param startIndex
3979     *            the first index to start joining from. It is an error to pass in a start index past the end of the
3980     *            array
3981     * @param endIndex
3982     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
3983     *            the array
3984     * @return the joined String, {@code null} if null array input
3985     * @since 3.2
3986     */
3987    public static String join(final char[] array, final char delimiter, final int startIndex, final int endIndex) {
3988        if (array == null) {
3989            return null;
3990        }
3991        if (endIndex - startIndex <= 0) {
3992            return EMPTY;
3993        }
3994        final StringBuilder stringBuilder = new StringBuilder(array.length * 2 - 1);
3995        for (int i = startIndex; i < endIndex; i++) {
3996            stringBuilder
3997                    .append(array[i])
3998                    .append(delimiter);
3999        }
4000        return stringBuilder.substring(0, stringBuilder.length() - 1);
4001    }
4002
4003    /**
4004     * Joins the elements of the provided array into a single String containing the provided list of elements.
4005     *
4006     * <p>
4007     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4008     * by empty strings.
4009     * </p>
4010     *
4011     * <pre>
4012     * StringUtils.join(null, *)               = null
4013     * StringUtils.join([], *)                 = ""
4014     * StringUtils.join([null], *)             = ""
4015     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4016     * StringUtils.join([1, 2, 3], null) = "123"
4017     * </pre>
4018     *
4019     * @param array
4020     *            the array of values to join together, may be null
4021     * @param delimiter
4022     *            the separator character to use
4023     * @return the joined String, {@code null} if null array input
4024     * @since 3.2
4025     */
4026    public static String join(final double[] array, final char delimiter) {
4027        if (array == null) {
4028            return null;
4029        }
4030        return join(array, delimiter, 0, array.length);
4031    }
4032
4033    /**
4034     * Joins the elements of the provided array into a single String containing the provided list of elements.
4035     *
4036     * <p>
4037     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4038     * by empty strings.
4039     * </p>
4040     *
4041     * <pre>
4042     * StringUtils.join(null, *)               = null
4043     * StringUtils.join([], *)                 = ""
4044     * StringUtils.join([null], *)             = ""
4045     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4046     * StringUtils.join([1, 2, 3], null) = "123"
4047     * </pre>
4048     *
4049     * @param array
4050     *            the array of values to join together, may be null
4051     * @param delimiter
4052     *            the separator character to use
4053     * @param startIndex
4054     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4055     *            array
4056     * @param endIndex
4057     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4058     *            the array
4059     * @return the joined String, {@code null} if null array input
4060     * @since 3.2
4061     */
4062    public static String join(final double[] array, final char delimiter, final int startIndex, final int endIndex) {
4063        if (array == null) {
4064            return null;
4065        }
4066        if (endIndex - startIndex <= 0) {
4067            return EMPTY;
4068        }
4069        final StringBuilder stringBuilder = new StringBuilder();
4070        for (int i = startIndex; i < endIndex; i++) {
4071            stringBuilder
4072                    .append(array[i])
4073                    .append(delimiter);
4074        }
4075        return stringBuilder.substring(0, stringBuilder.length() - 1);
4076    }
4077
4078    /**
4079     * Joins the elements of the provided array into a single String containing the provided list of elements.
4080     *
4081     * <p>
4082     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4083     * by empty strings.
4084     * </p>
4085     *
4086     * <pre>
4087     * StringUtils.join(null, *)               = null
4088     * StringUtils.join([], *)                 = ""
4089     * StringUtils.join([null], *)             = ""
4090     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4091     * StringUtils.join([1, 2, 3], null) = "123"
4092     * </pre>
4093     *
4094     * @param array
4095     *            the array of values to join together, may be null
4096     * @param delimiter
4097     *            the separator character to use
4098     * @return the joined String, {@code null} if null array input
4099     * @since 3.2
4100     */
4101    public static String join(final float[] array, final char delimiter) {
4102        if (array == null) {
4103            return null;
4104        }
4105        return join(array, delimiter, 0, array.length);
4106    }
4107
4108    /**
4109     * Joins the elements of the provided array into a single String containing the provided list of elements.
4110     *
4111     * <p>
4112     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4113     * by empty strings.
4114     * </p>
4115     *
4116     * <pre>
4117     * StringUtils.join(null, *)               = null
4118     * StringUtils.join([], *)                 = ""
4119     * StringUtils.join([null], *)             = ""
4120     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4121     * StringUtils.join([1, 2, 3], null) = "123"
4122     * </pre>
4123     *
4124     * @param array
4125     *            the array of values to join together, may be null
4126     * @param delimiter
4127     *            the separator character to use
4128     * @param startIndex
4129     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4130     *            array
4131     * @param endIndex
4132     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4133     *            the array
4134     * @return the joined String, {@code null} if null array input
4135     * @since 3.2
4136     */
4137    public static String join(final float[] array, final char delimiter, final int startIndex, final int endIndex) {
4138        if (array == null) {
4139            return null;
4140        }
4141        if (endIndex - startIndex <= 0) {
4142            return EMPTY;
4143        }
4144        final StringBuilder stringBuilder = new StringBuilder();
4145        for (int i = startIndex; i < endIndex; i++) {
4146            stringBuilder
4147                    .append(array[i])
4148                    .append(delimiter);
4149        }
4150        return stringBuilder.substring(0, stringBuilder.length() - 1);
4151    }
4152
4153    /**
4154     * Joins the elements of the provided array into a single String containing the provided list of elements.
4155     *
4156     * <p>
4157     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4158     * by empty strings.
4159     * </p>
4160     *
4161     * <pre>
4162     * StringUtils.join(null, *)               = null
4163     * StringUtils.join([], *)                 = ""
4164     * StringUtils.join([null], *)             = ""
4165     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4166     * StringUtils.join([1, 2, 3], null) = "123"
4167     * </pre>
4168     *
4169     * @param array
4170     *            the array of values to join together, may be null
4171     * @param separator
4172     *            the separator character to use
4173     * @return the joined String, {@code null} if null array input
4174     * @since 3.2
4175     */
4176    public static String join(final int[] array, final char separator) {
4177        if (array == null) {
4178            return null;
4179        }
4180        return join(array, separator, 0, array.length);
4181    }
4182
4183    /**
4184     * Joins the elements of the provided array into a single String containing the provided list of elements.
4185     *
4186     * <p>
4187     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4188     * by empty strings.
4189     * </p>
4190     *
4191     * <pre>
4192     * StringUtils.join(null, *)               = null
4193     * StringUtils.join([], *)                 = ""
4194     * StringUtils.join([null], *)             = ""
4195     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4196     * StringUtils.join([1, 2, 3], null) = "123"
4197     * </pre>
4198     *
4199     * @param array
4200     *            the array of values to join together, may be null
4201     * @param delimiter
4202     *            the separator character to use
4203     * @param startIndex
4204     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4205     *            array
4206     * @param endIndex
4207     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4208     *            the array
4209     * @return the joined String, {@code null} if null array input
4210     * @since 3.2
4211     */
4212    public static String join(final int[] array, final char delimiter, final int startIndex, final int endIndex) {
4213        if (array == null) {
4214            return null;
4215        }
4216        if (endIndex - startIndex <= 0) {
4217            return EMPTY;
4218        }
4219        final StringBuilder stringBuilder = new StringBuilder();
4220        for (int i = startIndex; i < endIndex; i++) {
4221            stringBuilder
4222                    .append(array[i])
4223                    .append(delimiter);
4224        }
4225        return stringBuilder.substring(0, stringBuilder.length() - 1);
4226    }
4227
4228    /**
4229     * Joins the elements of the provided {@link Iterable} into
4230     * a single String containing the provided elements.
4231     *
4232     * <p>No delimiter is added before or after the list. Null objects or empty
4233     * strings within the iteration are represented by empty strings.</p>
4234     *
4235     * <p>See the examples here: {@link #join(Object[],char)}.</p>
4236     *
4237     * @param iterable  the {@link Iterable} providing the values to join together, may be null
4238     * @param separator  the separator character to use
4239     * @return the joined String, {@code null} if null iterator input
4240     * @since 2.3
4241     */
4242    public static String join(final Iterable<?> iterable, final char separator) {
4243        return iterable != null ? join(iterable.iterator(), separator) : null;
4244    }
4245
4246    /**
4247     * Joins the elements of the provided {@link Iterable} into
4248     * a single String containing the provided elements.
4249     *
4250     * <p>No delimiter is added before or after the list.
4251     * A {@code null} separator is the same as an empty String ("").</p>
4252     *
4253     * <p>See the examples here: {@link #join(Object[],String)}.</p>
4254     *
4255     * @param iterable  the {@link Iterable} providing the values to join together, may be null
4256     * @param separator  the separator character to use, null treated as ""
4257     * @return the joined String, {@code null} if null iterator input
4258     * @since 2.3
4259     */
4260    public static String join(final Iterable<?> iterable, final String separator) {
4261        return iterable != null ? join(iterable.iterator(), separator) : null;
4262    }
4263
4264    /**
4265     * Joins the elements of the provided {@link Iterator} into
4266     * a single String containing the provided elements.
4267     *
4268     * <p>No delimiter is added before or after the list. Null objects or empty
4269     * strings within the iteration are represented by empty strings.</p>
4270     *
4271     * <p>See the examples here: {@link #join(Object[],char)}.</p>
4272     *
4273     * @param iterator  the {@link Iterator} of values to join together, may be null
4274     * @param separator  the separator character to use
4275     * @return the joined String, {@code null} if null iterator input
4276     * @since 2.0
4277     */
4278    public static String join(final Iterator<?> iterator, final char separator) {
4279        // handle null, zero and one elements before building a buffer
4280        if (iterator == null) {
4281            return null;
4282        }
4283        if (!iterator.hasNext()) {
4284            return EMPTY;
4285        }
4286        return Streams.of(iterator).collect(LangCollectors.joining(ObjectUtils.toString(String.valueOf(separator)), EMPTY, EMPTY, ObjectUtils::toString));
4287    }
4288
4289    /**
4290     * Joins the elements of the provided {@link Iterator} into
4291     * a single String containing the provided elements.
4292     *
4293     * <p>No delimiter is added before or after the list.
4294     * A {@code null} separator is the same as an empty String ("").</p>
4295     *
4296     * <p>See the examples here: {@link #join(Object[],String)}.</p>
4297     *
4298     * @param iterator  the {@link Iterator} of values to join together, may be null
4299     * @param separator  the separator character to use, null treated as ""
4300     * @return the joined String, {@code null} if null iterator input
4301     */
4302    public static String join(final Iterator<?> iterator, final String separator) {
4303        // handle null, zero and one elements before building a buffer
4304        if (iterator == null) {
4305            return null;
4306        }
4307        if (!iterator.hasNext()) {
4308            return EMPTY;
4309        }
4310        return Streams.of(iterator).collect(LangCollectors.joining(ObjectUtils.toString(separator), EMPTY, EMPTY, ObjectUtils::toString));
4311    }
4312
4313    /**
4314     * Joins the elements of the provided {@link List} into a single String
4315     * containing the provided list of elements.
4316     *
4317     * <p>No delimiter is added before or after the list.
4318     * Null objects or empty strings within the array are represented by
4319     * empty strings.</p>
4320     *
4321     * <pre>
4322     * StringUtils.join(null, *)               = null
4323     * StringUtils.join([], *)                 = ""
4324     * StringUtils.join([null], *)             = ""
4325     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4326     * StringUtils.join(["a", "b", "c"], null) = "abc"
4327     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4328     * </pre>
4329     *
4330     * @param list  the {@link List} of values to join together, may be null
4331     * @param separator  the separator character to use
4332     * @param startIndex the first index to start joining from.  It is
4333     * an error to pass in a start index past the end of the list
4334     * @param endIndex the index to stop joining from (exclusive). It is
4335     * an error to pass in an end index past the end of the list
4336     * @return the joined String, {@code null} if null list input
4337     * @since 3.8
4338     */
4339    public static String join(final List<?> list, final char separator, final int startIndex, final int endIndex) {
4340        if (list == null) {
4341            return null;
4342        }
4343        final int noOfItems = endIndex - startIndex;
4344        if (noOfItems <= 0) {
4345            return EMPTY;
4346        }
4347        final List<?> subList = list.subList(startIndex, endIndex);
4348        return join(subList.iterator(), separator);
4349    }
4350
4351    /**
4352     * Joins the elements of the provided {@link List} into a single String
4353     * containing the provided list of elements.
4354     *
4355     * <p>No delimiter is added before or after the list.
4356     * Null objects or empty strings within the array are represented by
4357     * empty strings.</p>
4358     *
4359     * <pre>
4360     * StringUtils.join(null, *)               = null
4361     * StringUtils.join([], *)                 = ""
4362     * StringUtils.join([null], *)             = ""
4363     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4364     * StringUtils.join(["a", "b", "c"], null) = "abc"
4365     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4366     * </pre>
4367     *
4368     * @param list  the {@link List} of values to join together, may be null
4369     * @param separator  the separator character to use
4370     * @param startIndex the first index to start joining from.  It is
4371     * an error to pass in a start index past the end of the list
4372     * @param endIndex the index to stop joining from (exclusive). It is
4373     * an error to pass in an end index past the end of the list
4374     * @return the joined String, {@code null} if null list input
4375     * @since 3.8
4376     */
4377    public static String join(final List<?> list, final String separator, final int startIndex, final int endIndex) {
4378        if (list == null) {
4379            return null;
4380        }
4381        final int noOfItems = endIndex - startIndex;
4382        if (noOfItems <= 0) {
4383            return EMPTY;
4384        }
4385        final List<?> subList = list.subList(startIndex, endIndex);
4386        return join(subList.iterator(), separator);
4387    }
4388
4389    /**
4390     * Joins the elements of the provided array into a single String containing the provided list of elements.
4391     *
4392     * <p>
4393     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4394     * by empty strings.
4395     * </p>
4396     *
4397     * <pre>
4398     * StringUtils.join(null, *)               = null
4399     * StringUtils.join([], *)                 = ""
4400     * StringUtils.join([null], *)             = ""
4401     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4402     * StringUtils.join([1, 2, 3], null) = "123"
4403     * </pre>
4404     *
4405     * @param array
4406     *            the array of values to join together, may be null
4407     * @param separator
4408     *            the separator character to use
4409     * @return the joined String, {@code null} if null array input
4410     * @since 3.2
4411     */
4412    public static String join(final long[] array, final char separator) {
4413        if (array == null) {
4414            return null;
4415        }
4416        return join(array, separator, 0, array.length);
4417    }
4418
4419    /**
4420     * Joins the elements of the provided array into a single String containing the provided list of elements.
4421     *
4422     * <p>
4423     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4424     * by empty strings.
4425     * </p>
4426     *
4427     * <pre>
4428     * StringUtils.join(null, *)               = null
4429     * StringUtils.join([], *)                 = ""
4430     * StringUtils.join([null], *)             = ""
4431     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4432     * StringUtils.join([1, 2, 3], null) = "123"
4433     * </pre>
4434     *
4435     * @param array
4436     *            the array of values to join together, may be null
4437     * @param delimiter
4438     *            the separator character to use
4439     * @param startIndex
4440     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4441     *            array
4442     * @param endIndex
4443     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4444     *            the array
4445     * @return the joined String, {@code null} if null array input
4446     * @since 3.2
4447     */
4448    public static String join(final long[] array, final char delimiter, final int startIndex, final int endIndex) {
4449        if (array == null) {
4450            return null;
4451        }
4452        if (endIndex - startIndex <= 0) {
4453            return EMPTY;
4454        }
4455        final StringBuilder stringBuilder = new StringBuilder();
4456        for (int i = startIndex; i < endIndex; i++) {
4457            stringBuilder
4458                    .append(array[i])
4459                    .append(delimiter);
4460        }
4461        return stringBuilder.substring(0, stringBuilder.length() - 1);
4462    }
4463
4464    /**
4465     * Joins the elements of the provided array into a single String
4466     * containing the provided list of elements.
4467     *
4468     * <p>No delimiter is added before or after the list.
4469     * Null objects or empty strings within the array are represented by
4470     * empty strings.</p>
4471     *
4472     * <pre>
4473     * StringUtils.join(null, *)               = null
4474     * StringUtils.join([], *)                 = ""
4475     * StringUtils.join([null], *)             = ""
4476     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4477     * StringUtils.join(["a", "b", "c"], null) = "abc"
4478     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4479     * </pre>
4480     *
4481     * @param array  the array of values to join together, may be null
4482     * @param delimiter  the separator character to use
4483     * @return the joined String, {@code null} if null array input
4484     * @since 2.0
4485     */
4486    public static String join(final Object[] array, final char delimiter) {
4487        if (array == null) {
4488            return null;
4489        }
4490        return join(array, delimiter, 0, array.length);
4491    }
4492
4493    /**
4494     * Joins the elements of the provided array into a single String
4495     * containing the provided list of elements.
4496     *
4497     * <p>No delimiter is added before or after the list.
4498     * Null objects or empty strings within the array are represented by
4499     * empty strings.</p>
4500     *
4501     * <pre>
4502     * StringUtils.join(null, *)               = null
4503     * StringUtils.join([], *)                 = ""
4504     * StringUtils.join([null], *)             = ""
4505     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
4506     * StringUtils.join(["a", "b", "c"], null) = "abc"
4507     * StringUtils.join([null, "", "a"], ';')  = ";;a"
4508     * </pre>
4509     *
4510     * @param array  the array of values to join together, may be null
4511     * @param delimiter  the separator character to use
4512     * @param startIndex the first index to start joining from.  It is
4513     * an error to pass in a start index past the end of the array
4514     * @param endIndex the index to stop joining from (exclusive). It is
4515     * an error to pass in an end index past the end of the array
4516     * @return the joined String, {@code null} if null array input
4517     * @since 2.0
4518     */
4519    public static String join(final Object[] array, final char delimiter, final int startIndex, final int endIndex) {
4520        return join(array, String.valueOf(delimiter), startIndex, endIndex);
4521    }
4522
4523    /**
4524     * Joins the elements of the provided array into a single String
4525     * containing the provided list of elements.
4526     *
4527     * <p>No delimiter is added before or after the list.
4528     * A {@code null} separator is the same as an empty String ("").
4529     * Null objects or empty strings within the array are represented by
4530     * empty strings.</p>
4531     *
4532     * <pre>
4533     * StringUtils.join(null, *)                = null
4534     * StringUtils.join([], *)                  = ""
4535     * StringUtils.join([null], *)              = ""
4536     * StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
4537     * StringUtils.join(["a", "b", "c"], null)  = "abc"
4538     * StringUtils.join(["a", "b", "c"], "")    = "abc"
4539     * StringUtils.join([null, "", "a"], ',')   = ",,a"
4540     * </pre>
4541     *
4542     * @param array  the array of values to join together, may be null
4543     * @param delimiter  the separator character to use, null treated as ""
4544     * @return the joined String, {@code null} if null array input
4545     */
4546    public static String join(final Object[] array, final String delimiter) {
4547        return array != null ? join(array, ObjectUtils.toString(delimiter), 0, array.length) : null;
4548    }
4549
4550    /**
4551     * Joins the elements of the provided array into a single String
4552     * containing the provided list of elements.
4553     *
4554     * <p>No delimiter is added before or after the list.
4555     * A {@code null} separator is the same as an empty String ("").
4556     * Null objects or empty strings within the array are represented by
4557     * empty strings.</p>
4558     *
4559     * <pre>
4560     * StringUtils.join(null, *, *, *)                = null
4561     * StringUtils.join([], *, *, *)                  = ""
4562     * StringUtils.join([null], *, *, *)              = ""
4563     * StringUtils.join(["a", "b", "c"], "--", 0, 3)  = "a--b--c"
4564     * StringUtils.join(["a", "b", "c"], "--", 1, 3)  = "b--c"
4565     * StringUtils.join(["a", "b", "c"], "--", 2, 3)  = "c"
4566     * StringUtils.join(["a", "b", "c"], "--", 2, 2)  = ""
4567     * StringUtils.join(["a", "b", "c"], null, 0, 3)  = "abc"
4568     * StringUtils.join(["a", "b", "c"], "", 0, 3)    = "abc"
4569     * StringUtils.join([null, "", "a"], ',', 0, 3)   = ",,a"
4570     * </pre>
4571     *
4572     * @param array  the array of values to join together, may be null
4573     * @param delimiter  the separator character to use, null treated as ""
4574     * @param startIndex the first index to start joining from.
4575     * @param endIndex the index to stop joining from (exclusive).
4576     * @return the joined String, {@code null} if null array input; or the empty string
4577     * if {@code endIndex - startIndex <= 0}. The number of joined entries is given by
4578     * {@code endIndex - startIndex}
4579     * @throws ArrayIndexOutOfBoundsException ife<br>
4580     * {@code startIndex < 0} or <br>
4581     * {@code startIndex >= array.length()} or <br>
4582     * {@code endIndex < 0} or <br>
4583     * {@code endIndex > array.length()}
4584     */
4585    public static String join(final Object[] array, final String delimiter, final int startIndex, final int endIndex) {
4586        return array != null ? Streams.of(array).skip(startIndex).limit(Math.max(0, endIndex - startIndex))
4587            .collect(LangCollectors.joining(delimiter, EMPTY, EMPTY, ObjectUtils::toString)) : null;
4588    }
4589
4590    /**
4591     * Joins the elements of the provided array into a single String containing the provided list of elements.
4592     *
4593     * <p>
4594     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4595     * by empty strings.
4596     * </p>
4597     *
4598     * <pre>
4599     * StringUtils.join(null, *)               = null
4600     * StringUtils.join([], *)                 = ""
4601     * StringUtils.join([null], *)             = ""
4602     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4603     * StringUtils.join([1, 2, 3], null) = "123"
4604     * </pre>
4605     *
4606     * @param array
4607     *            the array of values to join together, may be null
4608     * @param delimiter
4609     *            the separator character to use
4610     * @return the joined String, {@code null} if null array input
4611     * @since 3.2
4612     */
4613    public static String join(final short[] array, final char delimiter) {
4614        if (array == null) {
4615            return null;
4616        }
4617        return join(array, delimiter, 0, array.length);
4618    }
4619
4620    /**
4621     * Joins the elements of the provided array into a single String containing the provided list of elements.
4622     *
4623     * <p>
4624     * No delimiter is added before or after the list. Null objects or empty strings within the array are represented
4625     * by empty strings.
4626     * </p>
4627     *
4628     * <pre>
4629     * StringUtils.join(null, *)               = null
4630     * StringUtils.join([], *)                 = ""
4631     * StringUtils.join([null], *)             = ""
4632     * StringUtils.join([1, 2, 3], ';')  = "1;2;3"
4633     * StringUtils.join([1, 2, 3], null) = "123"
4634     * </pre>
4635     *
4636     * @param array
4637     *            the array of values to join together, may be null
4638     * @param delimiter
4639     *            the separator character to use
4640     * @param startIndex
4641     *            the first index to start joining from. It is an error to pass in a start index past the end of the
4642     *            array
4643     * @param endIndex
4644     *            the index to stop joining from (exclusive). It is an error to pass in an end index past the end of
4645     *            the array
4646     * @return the joined String, {@code null} if null array input
4647     * @since 3.2
4648     */
4649    public static String join(final short[] array, final char delimiter, final int startIndex, final int endIndex) {
4650        if (array == null) {
4651            return null;
4652        }
4653        if (endIndex - startIndex <= 0) {
4654            return EMPTY;
4655        }
4656        final StringBuilder stringBuilder = new StringBuilder();
4657        for (int i = startIndex; i < endIndex; i++) {
4658            stringBuilder
4659                    .append(array[i])
4660                    .append(delimiter);
4661        }
4662        return stringBuilder.substring(0, stringBuilder.length() - 1);
4663    }
4664
4665    /**
4666     * Joins the elements of the provided array into a single String
4667     * containing the provided list of elements.
4668     *
4669     * <p>No separator is added to the joined String.
4670     * Null objects or empty strings within the array are represented by
4671     * empty strings.</p>
4672     *
4673     * <pre>
4674     * StringUtils.join(null)            = null
4675     * StringUtils.join([])              = ""
4676     * StringUtils.join([null])          = ""
4677     * StringUtils.join(["a", "b", "c"]) = "abc"
4678     * StringUtils.join([null, "", "a"]) = "a"
4679     * </pre>
4680     *
4681     * @param <T> the specific type of values to join together
4682     * @param elements  the values to join together, may be null
4683     * @return the joined String, {@code null} if null array input
4684     * @since 2.0
4685     * @since 3.0 Changed signature to use varargs
4686     */
4687    @SafeVarargs
4688    public static <T> String join(final T... elements) {
4689        return join(elements, null);
4690    }
4691
4692    /**
4693     * Joins the elements of the provided varargs into a
4694     * single String containing the provided elements.
4695     *
4696     * <p>No delimiter is added before or after the list.
4697     * {@code null} elements and separator are treated as empty Strings ("").</p>
4698     *
4699     * <pre>
4700     * StringUtils.joinWith(",", {"a", "b"})        = "a,b"
4701     * StringUtils.joinWith(",", {"a", "b",""})     = "a,b,"
4702     * StringUtils.joinWith(",", {"a", null, "b"})  = "a,,b"
4703     * StringUtils.joinWith(null, {"a", "b"})       = "ab"
4704     * </pre>
4705     *
4706     * @param delimiter the separator character to use, null treated as ""
4707     * @param array the varargs providing the values to join together. {@code null} elements are treated as ""
4708     * @return the joined String.
4709     * @throws IllegalArgumentException if a null varargs is provided
4710     * @since 3.5
4711     */
4712    public static String joinWith(final String delimiter, final Object... array) {
4713        if (array == null) {
4714            throw new IllegalArgumentException("Object varargs must not be null");
4715        }
4716        return join(array, delimiter);
4717    }
4718
4719    /**
4720     * Finds the last index within a CharSequence, handling {@code null}.
4721     * This method uses {@link String#lastIndexOf(String)} if possible.
4722     *
4723     * <p>A {@code null} CharSequence will return {@code -1}.</p>
4724     *
4725     * <pre>
4726     * StringUtils.lastIndexOf(null, *)          = -1
4727     * StringUtils.lastIndexOf(*, null)          = -1
4728     * StringUtils.lastIndexOf("", "")           = 0
4729     * StringUtils.lastIndexOf("aabaabaa", "a")  = 7
4730     * StringUtils.lastIndexOf("aabaabaa", "b")  = 5
4731     * StringUtils.lastIndexOf("aabaabaa", "ab") = 4
4732     * StringUtils.lastIndexOf("aabaabaa", "")   = 8
4733     * </pre>
4734     *
4735     * @param seq  the CharSequence to check, may be null
4736     * @param searchSeq  the CharSequence to find, may be null
4737     * @return the last index of the search String,
4738     *  -1 if no match or {@code null} string input
4739     * @since 2.0
4740     * @since 3.0 Changed signature from lastIndexOf(String, String) to lastIndexOf(CharSequence, CharSequence)
4741     * @deprecated Use {@link Strings#lastIndexOf(CharSequence, CharSequence) Strings.CS.lastIndexOf(CharSequence, CharSequence)}
4742     */
4743    @Deprecated
4744    public static int lastIndexOf(final CharSequence seq, final CharSequence searchSeq) {
4745        return Strings.CS.lastIndexOf(seq, searchSeq);
4746    }
4747
4748    /**
4749     * Finds the last index within a CharSequence, handling {@code null}.
4750     * This method uses {@link String#lastIndexOf(String, int)} if possible.
4751     *
4752     * <p>A {@code null} CharSequence will return {@code -1}.
4753     * A negative start position returns {@code -1}.
4754     * An empty ("") search CharSequence always matches unless the start position is negative.
4755     * A start position greater than the string length searches the whole string.
4756     * The search starts at the startPos and works backwards; matches starting after the start
4757     * position are ignored.
4758     * </p>
4759     *
4760     * <pre>
4761     * StringUtils.lastIndexOf(null, *, *)          = -1
4762     * StringUtils.lastIndexOf(*, null, *)          = -1
4763     * StringUtils.lastIndexOf("aabaabaa", "a", 8)  = 7
4764     * StringUtils.lastIndexOf("aabaabaa", "b", 8)  = 5
4765     * StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
4766     * StringUtils.lastIndexOf("aabaabaa", "b", 9)  = 5
4767     * StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
4768     * StringUtils.lastIndexOf("aabaabaa", "a", 0)  = 0
4769     * StringUtils.lastIndexOf("aabaabaa", "b", 0)  = -1
4770     * StringUtils.lastIndexOf("aabaabaa", "b", 1)  = -1
4771     * StringUtils.lastIndexOf("aabaabaa", "b", 2)  = 2
4772     * StringUtils.lastIndexOf("aabaabaa", "ba", 2)  = 2
4773     * </pre>
4774     *
4775     * @param seq  the CharSequence to check, may be null
4776     * @param searchSeq  the CharSequence to find, may be null
4777     * @param startPos  the start position, negative treated as zero
4778     * @return the last index of the search CharSequence (always &le; startPos),
4779     *  -1 if no match or {@code null} string input
4780     * @since 2.0
4781     * @since 3.0 Changed signature from lastIndexOf(String, String, int) to lastIndexOf(CharSequence, CharSequence, int)
4782     * @deprecated Use {@link Strings#lastIndexOf(CharSequence, CharSequence, int) Strings.CS.lastIndexOf(CharSequence, CharSequence, int)}
4783     */
4784    @Deprecated
4785    public static int lastIndexOf(final CharSequence seq, final CharSequence searchSeq, final int startPos) {
4786        return Strings.CS.lastIndexOf(seq, searchSeq, startPos);
4787    }
4788
4789    /**
4790     * Returns the index within {@code seq} of the last occurrence of
4791     * the specified character. For values of {@code searchChar} in the
4792     * range from 0 to 0xFFFF (inclusive), the index (in Unicode code
4793     * units) returned is the largest value <em>k</em> such that:
4794     * <blockquote><pre>
4795     * this.charAt(<em>k</em>) == searchChar
4796     * </pre></blockquote>
4797     * is true. For other values of {@code searchChar}, it is the
4798     * largest value <em>k</em> such that:
4799     * <blockquote><pre>
4800     * this.codePointAt(<em>k</em>) == searchChar
4801     * </pre></blockquote>
4802     * is true.  In either case, if no such character occurs in this
4803     * string, then {@code -1} is returned. Furthermore, a {@code null} or empty ("")
4804     * {@link CharSequence} will return {@code -1}. The
4805     * {@code seq} {@link CharSequence} object is searched backwards
4806     * starting at the last character.
4807     *
4808     * <pre>
4809     * StringUtils.lastIndexOf(null, *)         = -1
4810     * StringUtils.lastIndexOf("", *)           = -1
4811     * StringUtils.lastIndexOf("aabaabaa", 'a') = 7
4812     * StringUtils.lastIndexOf("aabaabaa", 'b') = 5
4813     * </pre>
4814     *
4815     * @param seq  the {@link CharSequence} to check, may be null
4816     * @param searchChar  the character to find
4817     * @return the last index of the search character,
4818     *  -1 if no match or {@code null} string input
4819     * @since 2.0
4820     * @since 3.0 Changed signature from lastIndexOf(String, int) to lastIndexOf(CharSequence, int)
4821     * @since 3.6 Updated {@link CharSequenceUtils} call to behave more like {@link String}
4822     */
4823    public static int lastIndexOf(final CharSequence seq, final int searchChar) {
4824        if (isEmpty(seq)) {
4825            return INDEX_NOT_FOUND;
4826        }
4827        return CharSequenceUtils.lastIndexOf(seq, searchChar, seq.length());
4828    }
4829
4830    /**
4831     * Returns the index within {@code seq} of the last occurrence of
4832     * the specified character, searching backward starting at the
4833     * specified index. For values of {@code searchChar} in the range
4834     * from 0 to 0xFFFF (inclusive), the index returned is the largest
4835     * value <em>k</em> such that:
4836     * <blockquote><pre>
4837     * (this.charAt(<em>k</em>) == searchChar) &amp;&amp; (<em>k</em> &lt;= startPos)
4838     * </pre></blockquote>
4839     * is true. For other values of {@code searchChar}, it is the
4840     * largest value <em>k</em> such that:
4841     * <blockquote><pre>
4842     * (this.codePointAt(<em>k</em>) == searchChar) &amp;&amp; (<em>k</em> &lt;= startPos)
4843     * </pre></blockquote>
4844     * is true. In either case, if no such character occurs in {@code seq}
4845     * at or before position {@code startPos}, then
4846     * {@code -1} is returned. Furthermore, a {@code null} or empty ("")
4847     * {@link CharSequence} will return {@code -1}. A start position greater
4848     * than the string length searches the whole string.
4849     * The search starts at the {@code startPos} and works backwards;
4850     * matches starting after the start position are ignored.
4851     *
4852     * <p>All indices are specified in {@code char} values
4853     * (Unicode code units).
4854     *
4855     * <pre>
4856     * StringUtils.lastIndexOf(null, *, *)          = -1
4857     * StringUtils.lastIndexOf("", *,  *)           = -1
4858     * StringUtils.lastIndexOf("aabaabaa", 'b', 8)  = 5
4859     * StringUtils.lastIndexOf("aabaabaa", 'b', 4)  = 2
4860     * StringUtils.lastIndexOf("aabaabaa", 'b', 0)  = -1
4861     * StringUtils.lastIndexOf("aabaabaa", 'b', 9)  = 5
4862     * StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
4863     * StringUtils.lastIndexOf("aabaabaa", 'a', 0)  = 0
4864     * </pre>
4865     *
4866     * @param seq  the CharSequence to check, may be null
4867     * @param searchChar  the character to find
4868     * @param startPos  the start position
4869     * @return the last index of the search character (always &le; startPos),
4870     *  -1 if no match or {@code null} string input
4871     * @since 2.0
4872     * @since 3.0 Changed signature from lastIndexOf(String, int, int) to lastIndexOf(CharSequence, int, int)
4873     */
4874    public static int lastIndexOf(final CharSequence seq, final int searchChar, final int startPos) {
4875        if (isEmpty(seq)) {
4876            return INDEX_NOT_FOUND;
4877        }
4878        return CharSequenceUtils.lastIndexOf(seq, searchChar, startPos);
4879    }
4880
4881    /**
4882     * Find the latest index of any substring in a set of potential substrings.
4883     *
4884     * <p>A {@code null} CharSequence will return {@code -1}.
4885     * A {@code null} search array will return {@code -1}.
4886     * A {@code null} or zero length search array entry will be ignored,
4887     * but a search array containing "" will return the length of {@code str}
4888     * if {@code str} is not null. This method uses {@link String#indexOf(String)} if possible</p>
4889     *
4890     * <pre>
4891     * StringUtils.lastIndexOfAny(null, *)                    = -1
4892     * StringUtils.lastIndexOfAny(*, null)                    = -1
4893     * StringUtils.lastIndexOfAny(*, [])                      = -1
4894     * StringUtils.lastIndexOfAny(*, [null])                  = -1
4895     * StringUtils.lastIndexOfAny("zzabyycdxx", ["ab", "cd"]) = 6
4896     * StringUtils.lastIndexOfAny("zzabyycdxx", ["cd", "ab"]) = 6
4897     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", "op"]) = -1
4898     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", "op"]) = -1
4899     * StringUtils.lastIndexOfAny("zzabyycdxx", ["mn", ""])   = 10
4900     * </pre>
4901     *
4902     * @param str  the CharSequence to check, may be null
4903     * @param searchStrs  the CharSequences to search for, may be null
4904     * @return the last index of any of the CharSequences, -1 if no match
4905     * @since 3.0 Changed signature from lastIndexOfAny(String, String[]) to lastIndexOfAny(CharSequence, CharSequence)
4906     */
4907    public static int lastIndexOfAny(final CharSequence str, final CharSequence... searchStrs) {
4908        if (str == null || searchStrs == null) {
4909            return INDEX_NOT_FOUND;
4910        }
4911        int ret = INDEX_NOT_FOUND;
4912        int tmp;
4913        for (final CharSequence search : searchStrs) {
4914            if (search == null) {
4915                continue;
4916            }
4917            tmp = CharSequenceUtils.lastIndexOf(str, search, str.length());
4918            if (tmp > ret) {
4919                ret = tmp;
4920            }
4921        }
4922        return ret;
4923    }
4924
4925    /**
4926     * Case in-sensitive find of the last index within a CharSequence.
4927     *
4928     * <p>A {@code null} CharSequence will return {@code -1}.
4929     * A negative start position returns {@code -1}.
4930     * An empty ("") search CharSequence always matches unless the start position is negative.
4931     * A start position greater than the string length searches the whole string.</p>
4932     *
4933     * <pre>
4934     * StringUtils.lastIndexOfIgnoreCase(null, *)          = -1
4935     * StringUtils.lastIndexOfIgnoreCase(*, null)          = -1
4936     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A")  = 7
4937     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B")  = 5
4938     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB") = 4
4939     * </pre>
4940     *
4941     * @param str  the CharSequence to check, may be null
4942     * @param searchStr  the CharSequence to find, may be null
4943     * @return the first index of the search CharSequence,
4944     *  -1 if no match or {@code null} string input
4945     * @since 2.5
4946     * @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String) to lastIndexOfIgnoreCase(CharSequence, CharSequence)
4947     * @deprecated Use {@link Strings#lastIndexOf(CharSequence, CharSequence) Strings.CI.lastIndexOf(CharSequence, CharSequence)}
4948     */
4949    @Deprecated
4950    public static int lastIndexOfIgnoreCase(final CharSequence str, final CharSequence searchStr) {
4951        return Strings.CI.lastIndexOf(str, searchStr);
4952    }
4953
4954    /**
4955     * Case in-sensitive find of the last index within a CharSequence
4956     * from the specified position.
4957     *
4958     * <p>A {@code null} CharSequence will return {@code -1}.
4959     * A negative start position returns {@code -1}.
4960     * An empty ("") search CharSequence always matches unless the start position is negative.
4961     * A start position greater than the string length searches the whole string.
4962     * The search starts at the startPos and works backwards; matches starting after the start
4963     * position are ignored.
4964     * </p>
4965     *
4966     * <pre>
4967     * StringUtils.lastIndexOfIgnoreCase(null, *, *)          = -1
4968     * StringUtils.lastIndexOfIgnoreCase(*, null, *)          = -1
4969     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 8)  = 7
4970     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 8)  = 5
4971     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB", 8) = 4
4972     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 9)  = 5
4973     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", -1) = -1
4974     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 0)  = 0
4975     * StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 0)  = -1
4976     * </pre>
4977     *
4978     * @param str  the CharSequence to check, may be null
4979     * @param searchStr  the CharSequence to find, may be null
4980     * @param startPos  the start position
4981     * @return the last index of the search CharSequence (always &le; startPos),
4982     *  -1 if no match or {@code null} input
4983     * @since 2.5
4984     * @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String, int) to lastIndexOfIgnoreCase(CharSequence, CharSequence, int)
4985     * @deprecated Use {@link Strings#lastIndexOf(CharSequence, CharSequence, int) Strings.CI.lastIndexOf(CharSequence, CharSequence, int)}
4986     */
4987    @Deprecated
4988    public static int lastIndexOfIgnoreCase(final CharSequence str, final CharSequence searchStr, final int startPos) {
4989        return Strings.CI.lastIndexOf(str, searchStr, startPos);
4990    }
4991
4992    /**
4993     * Finds the n-th last index within a String, handling {@code null}.
4994     * This method uses {@link String#lastIndexOf(String)}.
4995     *
4996     * <p>A {@code null} String will return {@code -1}.</p>
4997     *
4998     * <pre>
4999     * StringUtils.lastOrdinalIndexOf(null, *, *)          = -1
5000     * StringUtils.lastOrdinalIndexOf(*, null, *)          = -1
5001     * StringUtils.lastOrdinalIndexOf("", "", *)           = 0
5002     * StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1)  = 7
5003     * StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2)  = 6
5004     * StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1)  = 5
5005     * StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2)  = 2
5006     * StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
5007     * StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
5008     * StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1)   = 8
5009     * StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2)   = 8
5010     * </pre>
5011     *
5012     * <p>Note that 'tail(CharSequence str, int n)' may be implemented as: </p>
5013     *
5014     * <pre>
5015     *   str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
5016     * </pre>
5017     *
5018     * @param str  the CharSequence to check, may be null
5019     * @param searchStr  the CharSequence to find, may be null
5020     * @param ordinal  the n-th last {@code searchStr} to find
5021     * @return the n-th last index of the search CharSequence,
5022     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5023     * @since 2.5
5024     * @since 3.0 Changed signature from lastOrdinalIndexOf(String, String, int) to lastOrdinalIndexOf(CharSequence, CharSequence, int)
5025     */
5026    public static int lastOrdinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal) {
5027        return ordinalIndexOf(str, searchStr, ordinal, true);
5028    }
5029
5030    /**
5031     * Gets the leftmost {@code len} characters of a String.
5032     *
5033     * <p>If {@code len} characters are not available, or the
5034     * String is {@code null}, the String will be returned without
5035     * an exception. An empty String is returned if len is negative.</p>
5036     *
5037     * <pre>
5038     * StringUtils.left(null, *)    = null
5039     * StringUtils.left(*, -ve)     = ""
5040     * StringUtils.left("", *)      = ""
5041     * StringUtils.left("abc", 0)   = ""
5042     * StringUtils.left("abc", 2)   = "ab"
5043     * StringUtils.left("abc", 4)   = "abc"
5044     * </pre>
5045     *
5046     * @param str  the String to get the leftmost characters from, may be null
5047     * @param len  the length of the required String
5048     * @return the leftmost characters, {@code null} if null String input
5049     */
5050    public static String left(final String str, final int len) {
5051        if (str == null) {
5052            return null;
5053        }
5054        if (len < 0) {
5055            return EMPTY;
5056        }
5057        if (str.length() <= len) {
5058            return str;
5059        }
5060        return str.substring(0, len);
5061    }
5062
5063    /**
5064     * Left pad a String with spaces (' ').
5065     *
5066     * <p>The String is padded to the size of {@code size}.</p>
5067     *
5068     * <pre>
5069     * StringUtils.leftPad(null, *)   = null
5070     * StringUtils.leftPad("", 3)     = "   "
5071     * StringUtils.leftPad("bat", 3)  = "bat"
5072     * StringUtils.leftPad("bat", 5)  = "  bat"
5073     * StringUtils.leftPad("bat", 1)  = "bat"
5074     * StringUtils.leftPad("bat", -1) = "bat"
5075     * </pre>
5076     *
5077     * @param str  the String to pad out, may be null
5078     * @param size  the size to pad to
5079     * @return left padded String or original String if no padding is necessary,
5080     *  {@code null} if null String input
5081     */
5082    public static String leftPad(final String str, final int size) {
5083        return leftPad(str, size, ' ');
5084    }
5085
5086    /**
5087     * Left pad a String with a specified character.
5088     *
5089     * <p>Pad to a size of {@code size}.</p>
5090     *
5091     * <pre>
5092     * StringUtils.leftPad(null, *, *)     = null
5093     * StringUtils.leftPad("", 3, 'z')     = "zzz"
5094     * StringUtils.leftPad("bat", 3, 'z')  = "bat"
5095     * StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
5096     * StringUtils.leftPad("bat", 1, 'z')  = "bat"
5097     * StringUtils.leftPad("bat", -1, 'z') = "bat"
5098     * </pre>
5099     *
5100     * @param str  the String to pad out, may be null
5101     * @param size  the size to pad to
5102     * @param padChar  the character to pad with
5103     * @return left padded String or original String if no padding is necessary,
5104     *  {@code null} if null String input
5105     * @since 2.0
5106     */
5107    public static String leftPad(final String str, final int size, final char padChar) {
5108        if (str == null) {
5109            return null;
5110        }
5111        final int pads = size - str.length();
5112        if (pads <= 0) {
5113            return str; // returns original String when possible
5114        }
5115        if (pads > PAD_LIMIT) {
5116            return leftPad(str, size, String.valueOf(padChar));
5117        }
5118        return repeat(padChar, pads).concat(str);
5119    }
5120
5121    /**
5122     * Left pad a String with a specified String.
5123     *
5124     * <p>Pad to a size of {@code size}.</p>
5125     *
5126     * <pre>
5127     * StringUtils.leftPad(null, *, *)      = null
5128     * StringUtils.leftPad("", 3, "z")      = "zzz"
5129     * StringUtils.leftPad("bat", 3, "yz")  = "bat"
5130     * StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
5131     * StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
5132     * StringUtils.leftPad("bat", 1, "yz")  = "bat"
5133     * StringUtils.leftPad("bat", -1, "yz") = "bat"
5134     * StringUtils.leftPad("bat", 5, null)  = "  bat"
5135     * StringUtils.leftPad("bat", 5, "")    = "  bat"
5136     * </pre>
5137     *
5138     * @param str  the String to pad out, may be null
5139     * @param size  the size to pad to
5140     * @param padStr  the String to pad with, null or empty treated as single space
5141     * @return left padded String or original String if no padding is necessary,
5142     *  {@code null} if null String input
5143     */
5144    public static String leftPad(final String str, final int size, String padStr) {
5145        if (str == null) {
5146            return null;
5147        }
5148        if (isEmpty(padStr)) {
5149            padStr = SPACE;
5150        }
5151        final int padLen = padStr.length();
5152        final int strLen = str.length();
5153        final int pads = size - strLen;
5154        if (pads <= 0) {
5155            return str; // returns original String when possible
5156        }
5157        if (padLen == 1 && pads <= PAD_LIMIT) {
5158            return leftPad(str, size, padStr.charAt(0));
5159        }
5160
5161        if (pads == padLen) {
5162            return padStr.concat(str);
5163        }
5164        if (pads < padLen) {
5165            return padStr.substring(0, pads).concat(str);
5166        }
5167        final char[] padding = new char[pads];
5168        final char[] padChars = padStr.toCharArray();
5169        for (int i = 0; i < pads; i++) {
5170            padding[i] = padChars[i % padLen];
5171        }
5172        return new String(padding).concat(str);
5173    }
5174
5175    /**
5176     * Gets a CharSequence length or {@code 0} if the CharSequence is
5177     * {@code null}.
5178     *
5179     * @param cs
5180     *            a CharSequence or {@code null}
5181     * @return CharSequence length or {@code 0} if the CharSequence is
5182     *         {@code null}.
5183     * @since 2.4
5184     * @since 3.0 Changed signature from length(String) to length(CharSequence)
5185     */
5186    public static int length(final CharSequence cs) {
5187        return cs == null ? 0 : cs.length();
5188    }
5189
5190    /**
5191     * Converts a String to lower case as per {@link String#toLowerCase()}.
5192     *
5193     * <p>A {@code null} input String returns {@code null}.</p>
5194     *
5195     * <pre>
5196     * StringUtils.lowerCase(null)  = null
5197     * StringUtils.lowerCase("")    = ""
5198     * StringUtils.lowerCase("aBc") = "abc"
5199     * </pre>
5200     *
5201     * <p><strong>Note:</strong> As described in the documentation for {@link String#toLowerCase()},
5202     * the result of this method is affected by the current locale.
5203     * For platform-independent case transformations, the method {@link #lowerCase(String, Locale)}
5204     * should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
5205     *
5206     * @param str  the String to lower case, may be null
5207     * @return the lower cased String, {@code null} if null String input
5208     */
5209    public static String lowerCase(final String str) {
5210        if (str == null) {
5211            return null;
5212        }
5213        return str.toLowerCase();
5214    }
5215
5216    /**
5217     * Converts a String to lower case as per {@link String#toLowerCase(Locale)}.
5218     *
5219     * <p>A {@code null} input String returns {@code null}.</p>
5220     *
5221     * <pre>
5222     * StringUtils.lowerCase(null, Locale.ENGLISH)  = null
5223     * StringUtils.lowerCase("", Locale.ENGLISH)    = ""
5224     * StringUtils.lowerCase("aBc", Locale.ENGLISH) = "abc"
5225     * </pre>
5226     *
5227     * @param str  the String to lower case, may be null
5228     * @param locale  the locale that defines the case transformation rules, must not be null
5229     * @return the lower cased String, {@code null} if null String input
5230     * @since 2.5
5231     */
5232    public static String lowerCase(final String str, final Locale locale) {
5233        if (str == null) {
5234            return null;
5235        }
5236        return str.toLowerCase(LocaleUtils.toLocale(locale));
5237    }
5238
5239    private static int[] matches(final CharSequence first, final CharSequence second) {
5240        final CharSequence max;
5241        final CharSequence min;
5242        if (first.length() > second.length()) {
5243            max = first;
5244            min = second;
5245        } else {
5246            max = second;
5247            min = first;
5248        }
5249        final int range = Math.max(max.length() / 2 - 1, 0);
5250        final int[] matchIndexes = ArrayFill.fill(new int[min.length()], -1);
5251        final boolean[] matchFlags = new boolean[max.length()];
5252        int matches = 0;
5253        for (int mi = 0; mi < min.length(); mi++) {
5254            final char c1 = min.charAt(mi);
5255            for (int xi = Math.max(mi - range, 0), xn = Math.min(mi + range + 1, max.length()); xi < xn; xi++) {
5256                if (!matchFlags[xi] && c1 == max.charAt(xi)) {
5257                    matchIndexes[mi] = xi;
5258                    matchFlags[xi] = true;
5259                    matches++;
5260                    break;
5261                }
5262            }
5263        }
5264        final char[] ms1 = new char[matches];
5265        final char[] ms2 = new char[matches];
5266        for (int i = 0, si = 0; i < min.length(); i++) {
5267            if (matchIndexes[i] != -1) {
5268                ms1[si] = min.charAt(i);
5269                si++;
5270            }
5271        }
5272        for (int i = 0, si = 0; i < max.length(); i++) {
5273            if (matchFlags[i]) {
5274                ms2[si] = max.charAt(i);
5275                si++;
5276            }
5277        }
5278        int transpositions = 0;
5279        for (int mi = 0; mi < ms1.length; mi++) {
5280            if (ms1[mi] != ms2[mi]) {
5281                transpositions++;
5282            }
5283        }
5284        int prefix = 0;
5285        for (int mi = 0; mi < min.length(); mi++) {
5286            if (first.charAt(mi) != second.charAt(mi)) {
5287                break;
5288            }
5289            prefix++;
5290        }
5291        return new int[] { matches, transpositions / 2, prefix, max.length() };
5292    }
5293
5294    /**
5295     * Gets {@code len} characters from the middle of a String.
5296     *
5297     * <p>If {@code len} characters are not available, the remainder
5298     * of the String will be returned without an exception. If the
5299     * String is {@code null}, {@code null} will be returned.
5300     * An empty String is returned if len is negative or exceeds the
5301     * length of {@code str}.</p>
5302     *
5303     * <pre>
5304     * StringUtils.mid(null, *, *)    = null
5305     * StringUtils.mid(*, *, -ve)     = ""
5306     * StringUtils.mid("", 0, *)      = ""
5307     * StringUtils.mid("abc", 0, 2)   = "ab"
5308     * StringUtils.mid("abc", 0, 4)   = "abc"
5309     * StringUtils.mid("abc", 2, 4)   = "c"
5310     * StringUtils.mid("abc", 4, 2)   = ""
5311     * StringUtils.mid("abc", -2, 2)  = "ab"
5312     * </pre>
5313     *
5314     * @param str  the String to get the characters from, may be null
5315     * @param pos  the position to start from, negative treated as zero
5316     * @param len  the length of the required String
5317     * @return the middle characters, {@code null} if null String input
5318     */
5319    public static String mid(final String str, int pos, final int len) {
5320        if (str == null) {
5321            return null;
5322        }
5323        if (len < 0 || pos > str.length()) {
5324            return EMPTY;
5325        }
5326        if (pos < 0) {
5327            pos = 0;
5328        }
5329        if (str.length() <= pos + len) {
5330            return str.substring(pos);
5331        }
5332        return str.substring(pos, pos + len);
5333    }
5334
5335    /**
5336     * Similar to <a
5337     * href="https://www.w3.org/TR/xpath/#function-normalize-space">https://www.w3.org/TR/xpath/#function-normalize
5338     * -space</a>
5339     *
5340     * <p>
5341     * The function returns the argument string with whitespace normalized by using
5342     * {@code {@link #trim(String)}} to remove leading and trailing whitespace
5343     * and then replacing sequences of whitespace characters by a single space.
5344     * </p>
5345     * In XML Whitespace characters are the same as those allowed by the <a
5346     * href="https://www.w3.org/TR/REC-xml/#NT-S">S</a> production, which is S ::= (#x20 | #x9 | #xD | #xA)+
5347     * <p>
5348     * Java's regexp pattern \s defines whitespace as [ \t\n\x0B\f\r]
5349     *
5350     * <p>For reference:</p>
5351     * <ul>
5352     * <li>\x0B = vertical tab</li>
5353     * <li>\f = #xC = form feed</li>
5354     * <li>#x20 = space</li>
5355     * <li>#x9 = \t</li>
5356     * <li>#xA = \n</li>
5357     * <li>#xD = \r</li>
5358     * </ul>
5359     *
5360     * <p>
5361     * The difference is that Java's whitespace includes vertical tab and form feed, which this functional will also
5362     * normalize. Additionally {@code {@link #trim(String)}} removes control characters (char &lt;= 32) from both
5363     * ends of this String.
5364     * </p>
5365     *
5366     * @see Pattern
5367     * @see #trim(String)
5368     * @see <a
5369     *      href="https://www.w3.org/TR/xpath/#function-normalize-space">https://www.w3.org/TR/xpath/#function-normalize-space</a>
5370     * @param str the source String to normalize whitespaces from, may be null
5371     * @return the modified string with whitespace normalized, {@code null} if null String input
5372     * @since 3.0
5373     */
5374    public static String normalizeSpace(final String str) {
5375        // LANG-1020: Improved performance significantly by normalizing manually instead of using regex
5376        // See https://github.com/librucha/commons-lang-normalizespaces-benchmark for performance test
5377        if (isEmpty(str)) {
5378            return str;
5379        }
5380        final int size = str.length();
5381        final char[] newChars = new char[size];
5382        int count = 0;
5383        int whitespacesCount = 0;
5384        boolean startWhitespaces = true;
5385        for (int i = 0; i < size; i++) {
5386            final char actualChar = str.charAt(i);
5387            final boolean isWhitespace = Character.isWhitespace(actualChar);
5388            if (isWhitespace) {
5389                if (whitespacesCount == 0 && !startWhitespaces) {
5390                    newChars[count++] = SPACE.charAt(0);
5391                }
5392                whitespacesCount++;
5393            } else {
5394                startWhitespaces = false;
5395                newChars[count++] = actualChar == 160 ? 32 : actualChar;
5396                whitespacesCount = 0;
5397            }
5398        }
5399        if (startWhitespaces) {
5400            return EMPTY;
5401        }
5402        return new String(newChars, 0, count - (whitespacesCount > 0 ? 1 : 0)).trim();
5403    }
5404
5405    /**
5406     * Finds the n-th index within a CharSequence, handling {@code null}.
5407     * This method uses {@link String#indexOf(String)} if possible.
5408     * <p><strong>Note:</strong> The code starts looking for a match at the start of the target,
5409     * incrementing the starting index by one after each successful match
5410     * (unless {@code searchStr} is an empty string in which case the position
5411     * is never incremented and {@code 0} is returned immediately).
5412     * This means that matches may overlap.</p>
5413     * <p>A {@code null} CharSequence will return {@code -1}.</p>
5414     *
5415     * <pre>
5416     * StringUtils.ordinalIndexOf(null, *, *)          = -1
5417     * StringUtils.ordinalIndexOf(*, null, *)          = -1
5418     * StringUtils.ordinalIndexOf("", "", *)           = 0
5419     * StringUtils.ordinalIndexOf("aabaabaa", "a", 1)  = 0
5420     * StringUtils.ordinalIndexOf("aabaabaa", "a", 2)  = 1
5421     * StringUtils.ordinalIndexOf("aabaabaa", "b", 1)  = 2
5422     * StringUtils.ordinalIndexOf("aabaabaa", "b", 2)  = 5
5423     * StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
5424     * StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
5425     * StringUtils.ordinalIndexOf("aabaabaa", "", 1)   = 0
5426     * StringUtils.ordinalIndexOf("aabaabaa", "", 2)   = 0
5427     * </pre>
5428     *
5429     * <p>Matches may overlap:</p>
5430     * <pre>
5431     * StringUtils.ordinalIndexOf("ababab", "aba", 1)   = 0
5432     * StringUtils.ordinalIndexOf("ababab", "aba", 2)   = 2
5433     * StringUtils.ordinalIndexOf("ababab", "aba", 3)   = -1
5434     *
5435     * StringUtils.ordinalIndexOf("abababab", "abab", 1) = 0
5436     * StringUtils.ordinalIndexOf("abababab", "abab", 2) = 2
5437     * StringUtils.ordinalIndexOf("abababab", "abab", 3) = 4
5438     * StringUtils.ordinalIndexOf("abababab", "abab", 4) = -1
5439     * </pre>
5440     *
5441     * <p>Note that 'head(CharSequence str, int n)' may be implemented as: </p>
5442     *
5443     * <pre>
5444     *   str.substring(0, lastOrdinalIndexOf(str, "\n", n))
5445     * </pre>
5446     *
5447     * @param str  the CharSequence to check, may be null
5448     * @param searchStr  the CharSequence to find, may be null
5449     * @param ordinal  the n-th {@code searchStr} to find
5450     * @return the n-th index of the search CharSequence,
5451     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5452     * @since 2.1
5453     * @since 3.0 Changed signature from ordinalIndexOf(String, String, int) to ordinalIndexOf(CharSequence, CharSequence, int)
5454     */
5455    public static int ordinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal) {
5456        return ordinalIndexOf(str, searchStr, ordinal, false);
5457    }
5458
5459    /**
5460     * Finds the n-th index within a String, handling {@code null}.
5461     * This method uses {@link String#indexOf(String)} if possible.
5462     * <p>Note that matches may overlap<p>
5463     *
5464     * <p>A {@code null} CharSequence will return {@code -1}.</p>
5465     *
5466     * @param str  the CharSequence to check, may be null
5467     * @param searchStr  the CharSequence to find, may be null
5468     * @param ordinal  the n-th {@code searchStr} to find, overlapping matches are allowed.
5469     * @param lastIndex true if lastOrdinalIndexOf() otherwise false if ordinalIndexOf()
5470     * @return the n-th index of the search CharSequence,
5471     *  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
5472     */
5473    // Shared code between ordinalIndexOf(String, String, int) and lastOrdinalIndexOf(String, String, int)
5474    private static int ordinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal, final boolean lastIndex) {
5475        if (str == null || searchStr == null || ordinal <= 0) {
5476            return INDEX_NOT_FOUND;
5477        }
5478        if (searchStr.length() == 0) {
5479            return lastIndex ? str.length() : 0;
5480        }
5481        int found = 0;
5482        // set the initial index beyond the end of the string
5483        // this is to allow for the initial index decrement/increment
5484        int index = lastIndex ? str.length() : INDEX_NOT_FOUND;
5485        do {
5486            if (lastIndex) {
5487                index = CharSequenceUtils.lastIndexOf(str, searchStr, index - 1); // step backwards through string
5488            } else {
5489                index = CharSequenceUtils.indexOf(str, searchStr, index + 1); // step forwards through string
5490            }
5491            if (index < 0) {
5492                return index;
5493            }
5494            found++;
5495        } while (found < ordinal);
5496        return index;
5497    }
5498
5499    /**
5500     * Overlays part of a String with another String.
5501     *
5502     * <p>A {@code null} string input returns {@code null}.
5503     * A negative index is treated as zero.
5504     * An index greater than the string length is treated as the string length.
5505     * The start index is always the smaller of the two indices.</p>
5506     *
5507     * <pre>
5508     * StringUtils.overlay(null, *, *, *)            = null
5509     * StringUtils.overlay("", "abc", 0, 0)          = "abc"
5510     * StringUtils.overlay("abcdef", null, 2, 4)     = "abef"
5511     * StringUtils.overlay("abcdef", "", 2, 4)       = "abef"
5512     * StringUtils.overlay("abcdef", "", 4, 2)       = "abef"
5513     * StringUtils.overlay("abcdef", "zzzz", 2, 4)   = "abzzzzef"
5514     * StringUtils.overlay("abcdef", "zzzz", 4, 2)   = "abzzzzef"
5515     * StringUtils.overlay("abcdef", "zzzz", -1, 4)  = "zzzzef"
5516     * StringUtils.overlay("abcdef", "zzzz", 2, 8)   = "abzzzz"
5517     * StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
5518     * StringUtils.overlay("abcdef", "zzzz", 8, 10)  = "abcdefzzzz"
5519     * </pre>
5520     *
5521     * @param str  the String to do overlaying in, may be null
5522     * @param overlay  the String to overlay, may be null
5523     * @param start  the position to start overlaying at
5524     * @param end  the position to stop overlaying before
5525     * @return overlayed String, {@code null} if null String input
5526     * @since 2.0
5527     */
5528    public static String overlay(final String str, String overlay, int start, int end) {
5529        if (str == null) {
5530            return null;
5531        }
5532        if (overlay == null) {
5533            overlay = EMPTY;
5534        }
5535        final int len = str.length();
5536        if (start < 0) {
5537            start = 0;
5538        }
5539        if (start > len) {
5540            start = len;
5541        }
5542        if (end < 0) {
5543            end = 0;
5544        }
5545        if (end > len) {
5546            end = len;
5547        }
5548        if (start > end) {
5549            final int temp = start;
5550            start = end;
5551            end = temp;
5552        }
5553        return str.substring(0, start) +
5554            overlay +
5555            str.substring(end);
5556    }
5557
5558    /**
5559     * Prepends the prefix to the start of the string if the string does not already start with any of the prefixes.
5560     *
5561     * <pre>
5562     * StringUtils.prependIfMissing(null, null) = null
5563     * StringUtils.prependIfMissing("abc", null) = "abc"
5564     * StringUtils.prependIfMissing("", "xyz") = "xyz"
5565     * StringUtils.prependIfMissing("abc", "xyz") = "xyzabc"
5566     * StringUtils.prependIfMissing("xyzabc", "xyz") = "xyzabc"
5567     * StringUtils.prependIfMissing("XYZabc", "xyz") = "xyzXYZabc"
5568     * </pre>
5569     * <p>
5570     * With additional prefixes,
5571     * </p>
5572     *
5573     * <pre>
5574     * StringUtils.prependIfMissing(null, null, null) = null
5575     * StringUtils.prependIfMissing("abc", null, null) = "abc"
5576     * StringUtils.prependIfMissing("", "xyz", null) = "xyz"
5577     * StringUtils.prependIfMissing("abc", "xyz", new CharSequence[]{null}) = "xyzabc"
5578     * StringUtils.prependIfMissing("abc", "xyz", "") = "abc"
5579     * StringUtils.prependIfMissing("abc", "xyz", "mno") = "xyzabc"
5580     * StringUtils.prependIfMissing("xyzabc", "xyz", "mno") = "xyzabc"
5581     * StringUtils.prependIfMissing("mnoabc", "xyz", "mno") = "mnoabc"
5582     * StringUtils.prependIfMissing("XYZabc", "xyz", "mno") = "xyzXYZabc"
5583     * StringUtils.prependIfMissing("MNOabc", "xyz", "mno") = "xyzMNOabc"
5584     * </pre>
5585     *
5586     * @param str      The string.
5587     * @param prefix   The prefix to prepend to the start of the string.
5588     * @param prefixes Additional prefixes that are valid.
5589     * @return A new String if prefix was prepended, the same string otherwise.
5590     * @since 3.2
5591     * @deprecated Use {@link Strings#prependIfMissing(String, CharSequence, CharSequence...) Strings.CS.prependIfMissing(String, CharSequence,
5592     *             CharSequence...)}
5593     */
5594    @Deprecated
5595    public static String prependIfMissing(final String str, final CharSequence prefix, final CharSequence... prefixes) {
5596        return Strings.CS.prependIfMissing(str, prefix, prefixes);
5597    }
5598
5599    /**
5600     * Prepends the prefix to the start of the string if the string does not
5601     * already start, case-insensitive, with any of the prefixes.
5602     *
5603     * <pre>
5604     * StringUtils.prependIfMissingIgnoreCase(null, null) = null
5605     * StringUtils.prependIfMissingIgnoreCase("abc", null) = "abc"
5606     * StringUtils.prependIfMissingIgnoreCase("", "xyz") = "xyz"
5607     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz") = "xyzabc"
5608     * StringUtils.prependIfMissingIgnoreCase("xyzabc", "xyz") = "xyzabc"
5609     * StringUtils.prependIfMissingIgnoreCase("XYZabc", "xyz") = "XYZabc"
5610     * </pre>
5611     * <p>With additional prefixes,</p>
5612     * <pre>
5613     * StringUtils.prependIfMissingIgnoreCase(null, null, null) = null
5614     * StringUtils.prependIfMissingIgnoreCase("abc", null, null) = "abc"
5615     * StringUtils.prependIfMissingIgnoreCase("", "xyz", null) = "xyz"
5616     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", new CharSequence[]{null}) = "xyzabc"
5617     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", "") = "abc"
5618     * StringUtils.prependIfMissingIgnoreCase("abc", "xyz", "mno") = "xyzabc"
5619     * StringUtils.prependIfMissingIgnoreCase("xyzabc", "xyz", "mno") = "xyzabc"
5620     * StringUtils.prependIfMissingIgnoreCase("mnoabc", "xyz", "mno") = "mnoabc"
5621     * StringUtils.prependIfMissingIgnoreCase("XYZabc", "xyz", "mno") = "XYZabc"
5622     * StringUtils.prependIfMissingIgnoreCase("MNOabc", "xyz", "mno") = "MNOabc"
5623     * </pre>
5624     *
5625     * @param str The string.
5626     * @param prefix The prefix to prepend to the start of the string.
5627     * @param prefixes Additional prefixes that are valid (optional).
5628     * @return A new String if prefix was prepended, the same string otherwise.
5629     * @since 3.2
5630     * @deprecated Use {@link Strings#prependIfMissing(String, CharSequence, CharSequence...) Strings.CI.prependIfMissing(String, CharSequence,
5631     *             CharSequence...)}
5632     */
5633    @Deprecated
5634    public static String prependIfMissingIgnoreCase(final String str, final CharSequence prefix, final CharSequence... prefixes) {
5635        return Strings.CI.prependIfMissing(str, prefix, prefixes);
5636    }
5637
5638    /**
5639     * Removes all occurrences of a character from within the source string.
5640     *
5641     * <p>A {@code null} source string will return {@code null}.
5642     * An empty ("") source string will return the empty string.</p>
5643     *
5644     * <pre>
5645     * StringUtils.remove(null, *)       = null
5646     * StringUtils.remove("", *)         = ""
5647     * StringUtils.remove("queued", 'u') = "qeed"
5648     * StringUtils.remove("queued", 'z') = "queued"
5649     * </pre>
5650     *
5651     * @param str  the source String to search, may be null
5652     * @param remove  the char to search for and remove, may be null
5653     * @return the substring with the char removed if found,
5654     *  {@code null} if null String input
5655     * @since 2.1
5656     */
5657    public static String remove(final String str, final char remove) {
5658        if (isEmpty(str) || str.indexOf(remove) == INDEX_NOT_FOUND) {
5659            return str;
5660        }
5661        final char[] chars = str.toCharArray();
5662        int pos = 0;
5663        for (int i = 0; i < chars.length; i++) {
5664            if (chars[i] != remove) {
5665                chars[pos++] = chars[i];
5666            }
5667        }
5668        return new String(chars, 0, pos);
5669    }
5670
5671    /**
5672     * Removes all occurrences of a substring from within the source string.
5673     *
5674     * <p>A {@code null} source string will return {@code null}.
5675     * An empty ("") source string will return the empty string.
5676     * A {@code null} remove string will return the source string.
5677     * An empty ("") remove string will return the source string.</p>
5678     *
5679     * <pre>
5680     * StringUtils.remove(null, *)        = null
5681     * StringUtils.remove("", *)          = ""
5682     * StringUtils.remove(*, null)        = *
5683     * StringUtils.remove(*, "")          = *
5684     * StringUtils.remove("queued", "ue") = "qd"
5685     * StringUtils.remove("queued", "zz") = "queued"
5686     * </pre>
5687     *
5688     * @param str  the source String to search, may be null
5689     * @param remove  the String to search for and remove, may be null
5690     * @return the substring with the string removed if found,
5691     *  {@code null} if null String input
5692     * @since 2.1
5693     * @deprecated Use {@link Strings#remove(String, String) Strings.CS.remove(String, String)}
5694     */
5695    @Deprecated
5696    public static String remove(final String str, final String remove) {
5697        return Strings.CS.remove(str, remove);
5698    }
5699
5700    /**
5701     * Removes each substring of the text String that matches the given regular expression.
5702     *
5703     * This method is a {@code null} safe equivalent to:
5704     * <ul>
5705     *  <li>{@code text.replaceAll(regex, StringUtils.EMPTY)}</li>
5706     *  <li>{@code Pattern.compile(regex).matcher(text).replaceAll(StringUtils.EMPTY)}</li>
5707     * </ul>
5708     *
5709     * <p>A {@code null} reference passed to this method is a no-op.</p>
5710     *
5711     * <p>Unlike in the {@link #removePattern(String, String)} method, the {@link Pattern#DOTALL} option
5712     * is NOT automatically added.
5713     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
5714     * DOTALL is also known as single-line mode in Perl.</p>
5715     *
5716     * <pre>{@code
5717     * StringUtils.removeAll(null, *)      = null
5718     * StringUtils.removeAll("any", (String) null)  = "any"
5719     * StringUtils.removeAll("any", "")    = "any"
5720     * StringUtils.removeAll("any", ".*")  = ""
5721     * StringUtils.removeAll("any", ".+")  = ""
5722     * StringUtils.removeAll("abc", ".?")  = ""
5723     * StringUtils.removeAll("A<__>\n<__>B", "<.*>")      = "A\nB"
5724     * StringUtils.removeAll("A<__>\n<__>B", "(?s)<.*>")  = "AB"
5725     * StringUtils.removeAll("ABCabc123abc", "[a-z]")     = "ABC123"
5726     * }</pre>
5727     *
5728     * @param text  text to remove from, may be null
5729     * @param regex  the regular expression to which this string is to be matched
5730     * @return  the text with any removes processed,
5731     *              {@code null} if null String input
5732     *
5733     * @throws  java.util.regex.PatternSyntaxException
5734     *              if the regular expression's syntax is invalid
5735     *
5736     * @see #replaceAll(String, String, String)
5737     * @see #removePattern(String, String)
5738     * @see String#replaceAll(String, String)
5739     * @see java.util.regex.Pattern
5740     * @see java.util.regex.Pattern#DOTALL
5741     * @since 3.5
5742     * @deprecated Moved to RegExUtils.
5743     */
5744    @Deprecated
5745    public static String removeAll(final String text, final String regex) {
5746        return RegExUtils.removeAll(text, regex);
5747    }
5748
5749    /**
5750     * Removes a substring only if it is at the end of a source string,
5751     * otherwise returns the source string.
5752     *
5753     * <p>A {@code null} source string will return {@code null}.
5754     * An empty ("") source string will return the empty string.
5755     * A {@code null} search string will return the source string.</p>
5756     *
5757     * <pre>
5758     * StringUtils.removeEnd(null, *)      = null
5759     * StringUtils.removeEnd("", *)        = ""
5760     * StringUtils.removeEnd(*, null)      = *
5761     * StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
5762     * StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
5763     * StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
5764     * StringUtils.removeEnd("abc", "")    = "abc"
5765     * </pre>
5766     *
5767     * @param str  the source String to search, may be null
5768     * @param remove  the String to search for and remove, may be null
5769     * @return the substring with the string removed if found,
5770     *  {@code null} if null String input
5771     * @since 2.1
5772     * @deprecated Use {@link Strings#removeEnd(String, CharSequence) Strings.CS.removeEnd(String, CharSequence)}
5773     */
5774    @Deprecated
5775    public static String removeEnd(final String str, final String remove) {
5776        return Strings.CS.removeEnd(str, remove);
5777    }
5778
5779    /**
5780     * Case-insensitive removal of a substring if it is at the end of a source string,
5781     * otherwise returns the source string.
5782     *
5783     * <p>A {@code null} source string will return {@code null}.
5784     * An empty ("") source string will return the empty string.
5785     * A {@code null} search string will return the source string.</p>
5786     *
5787     * <pre>
5788     * StringUtils.removeEndIgnoreCase(null, *)      = null
5789     * StringUtils.removeEndIgnoreCase("", *)        = ""
5790     * StringUtils.removeEndIgnoreCase(*, null)      = *
5791     * StringUtils.removeEndIgnoreCase("www.domain.com", ".com.")  = "www.domain.com"
5792     * StringUtils.removeEndIgnoreCase("www.domain.com", ".com")   = "www.domain"
5793     * StringUtils.removeEndIgnoreCase("www.domain.com", "domain") = "www.domain.com"
5794     * StringUtils.removeEndIgnoreCase("abc", "")    = "abc"
5795     * StringUtils.removeEndIgnoreCase("www.domain.com", ".COM") = "www.domain")
5796     * StringUtils.removeEndIgnoreCase("www.domain.COM", ".com") = "www.domain")
5797     * </pre>
5798     *
5799     * @param str  the source String to search, may be null
5800     * @param remove  the String to search for (case-insensitive) and remove, may be null
5801     * @return the substring with the string removed if found,
5802     *  {@code null} if null String input
5803     * @since 2.4
5804     * @deprecated Use {@link Strings#removeEnd(String, CharSequence) Strings.CI.removeEnd(String, CharSequence)}
5805     */
5806    @Deprecated
5807    public static String removeEndIgnoreCase(final String str, final String remove) {
5808        return Strings.CI.removeEnd(str, remove);
5809    }
5810
5811    /**
5812     * Removes the first substring of the text string that matches the given regular expression.
5813     *
5814     * This method is a {@code null} safe equivalent to:
5815     * <ul>
5816     *  <li>{@code text.replaceFirst(regex, StringUtils.EMPTY)}</li>
5817     *  <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(StringUtils.EMPTY)}</li>
5818     * </ul>
5819     *
5820     * <p>A {@code null} reference passed to this method is a no-op.</p>
5821     *
5822     * <p>The {@link Pattern#DOTALL} option is NOT automatically added.
5823     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
5824     * DOTALL is also known as single-line mode in Perl.</p>
5825     *
5826     * <pre>{@code
5827     * StringUtils.removeFirst(null, *)      = null
5828     * StringUtils.removeFirst("any", (String) null)  = "any"
5829     * StringUtils.removeFirst("any", "")    = "any"
5830     * StringUtils.removeFirst("any", ".*")  = ""
5831     * StringUtils.removeFirst("any", ".+")  = ""
5832     * StringUtils.removeFirst("abc", ".?")  = "bc"
5833     * StringUtils.removeFirst("A<__>\n<__>B", "<.*>")      = "A\n<__>B"
5834     * StringUtils.removeFirst("A<__>\n<__>B", "(?s)<.*>")  = "AB"
5835     * StringUtils.removeFirst("ABCabc123", "[a-z]")          = "ABCbc123"
5836     * StringUtils.removeFirst("ABCabc123abc", "[a-z]+")      = "ABC123abc"
5837     * }</pre>
5838     *
5839     * @param text  text to remove from, may be null
5840     * @param regex  the regular expression to which this string is to be matched
5841     * @return  the text with the first replacement processed,
5842     *              {@code null} if null String input
5843     *
5844     * @throws  java.util.regex.PatternSyntaxException
5845     *              if the regular expression's syntax is invalid
5846     *
5847     * @see #replaceFirst(String, String, String)
5848     * @see String#replaceFirst(String, String)
5849     * @see java.util.regex.Pattern
5850     * @see java.util.regex.Pattern#DOTALL
5851     * @since 3.5
5852     * @deprecated Moved to RegExUtils.
5853     */
5854    @Deprecated
5855    public static String removeFirst(final String text, final String regex) {
5856        return replaceFirst(text, regex, EMPTY);
5857    }
5858
5859    /**
5860     * Case-insensitive removal of all occurrences of a substring from within
5861     * the source string.
5862     *
5863     * <p>
5864     * A {@code null} source string will return {@code null}. An empty ("")
5865     * source string will return the empty string. A {@code null} remove string
5866     * will return the source string. An empty ("") remove string will return
5867     * the source string.
5868     * </p>
5869     *
5870     * <pre>
5871     * StringUtils.removeIgnoreCase(null, *)        = null
5872     * StringUtils.removeIgnoreCase("", *)          = ""
5873     * StringUtils.removeIgnoreCase(*, null)        = *
5874     * StringUtils.removeIgnoreCase(*, "")          = *
5875     * StringUtils.removeIgnoreCase("queued", "ue") = "qd"
5876     * StringUtils.removeIgnoreCase("queued", "zz") = "queued"
5877     * StringUtils.removeIgnoreCase("quEUed", "UE") = "qd"
5878     * StringUtils.removeIgnoreCase("queued", "zZ") = "queued"
5879     * </pre>
5880     *
5881     * @param str
5882     *            the source String to search, may be null
5883     * @param remove
5884     *            the String to search for (case-insensitive) and remove, may be
5885     *            null
5886     * @return the substring with the string removed if found, {@code null} if
5887     *         null String input
5888     * @since 3.5
5889     * @deprecated Use {@link Strings#remove(String, String) Strings.CI.remove(String, String)}
5890     */
5891    @Deprecated
5892    public static String removeIgnoreCase(final String str, final String remove) {
5893        return Strings.CI.remove(str, remove);
5894    }
5895
5896    /**
5897     * Removes each substring of the source String that matches the given regular expression using the DOTALL option.
5898     *
5899     * This call is a {@code null} safe equivalent to:
5900     * <ul>
5901     * <li>{@code source.replaceAll(&quot;(?s)&quot; + regex, StringUtils.EMPTY)}</li>
5902     * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(source).replaceAll(StringUtils.EMPTY)}</li>
5903     * </ul>
5904     *
5905     * <p>A {@code null} reference passed to this method is a no-op.</p>
5906     *
5907     * <pre>{@code
5908     * StringUtils.removePattern(null, *)       = null
5909     * StringUtils.removePattern("any", (String) null)   = "any"
5910     * StringUtils.removePattern("A<__>\n<__>B", "<.*>")  = "AB"
5911     * StringUtils.removePattern("ABCabc123", "[a-z]")    = "ABC123"
5912     * }</pre>
5913     *
5914     * @param source
5915     *            the source string
5916     * @param regex
5917     *            the regular expression to which this string is to be matched
5918     * @return The resulting {@link String}
5919     * @see #replacePattern(String, String, String)
5920     * @see String#replaceAll(String, String)
5921     * @see Pattern#DOTALL
5922     * @since 3.2
5923     * @since 3.5 Changed {@code null} reference passed to this method is a no-op.
5924     * @deprecated Moved to RegExUtils.
5925     */
5926    @Deprecated
5927    public static String removePattern(final String source, final String regex) {
5928        return RegExUtils.removePattern(source, regex);
5929    }
5930
5931    /**
5932     * Removes a char only if it is at the beginning of a source string,
5933     * otherwise returns the source string.
5934     *
5935     * <p>A {@code null} source string will return {@code null}.
5936     * An empty ("") source string will return the empty string.
5937     * A {@code null} search char will return the source string.</p>
5938     *
5939     * <pre>
5940     * StringUtils.removeStart(null, *)      = null
5941     * StringUtils.removeStart("", *)        = ""
5942     * StringUtils.removeStart(*, null)      = *
5943     * StringUtils.removeStart("/path", '/') = "path"
5944     * StringUtils.removeStart("path", '/')  = "path"
5945     * StringUtils.removeStart("path", 0)    = "path"
5946     * </pre>
5947     *
5948     * @param str  the source String to search, may be null.
5949     * @param remove  the char to search for and remove.
5950     * @return the substring with the char removed if found,
5951     *  {@code null} if null String input.
5952     * @since 3.13.0
5953     */
5954    public static String removeStart(final String str, final char remove) {
5955        if (isEmpty(str)) {
5956            return str;
5957        }
5958        return str.charAt(0) == remove ? str.substring(1) : str;
5959    }
5960
5961    /**
5962     * Removes a substring only if it is at the beginning of a source string,
5963     * otherwise returns the source string.
5964     *
5965     * <p>A {@code null} source string will return {@code null}.
5966     * An empty ("") source string will return the empty string.
5967     * A {@code null} search string will return the source string.</p>
5968     *
5969     * <pre>
5970     * StringUtils.removeStart(null, *)      = null
5971     * StringUtils.removeStart("", *)        = ""
5972     * StringUtils.removeStart(*, null)      = *
5973     * StringUtils.removeStart("www.domain.com", "www.")   = "domain.com"
5974     * StringUtils.removeStart("domain.com", "www.")       = "domain.com"
5975     * StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
5976     * StringUtils.removeStart("abc", "")    = "abc"
5977     * </pre>
5978     *
5979     * @param str  the source String to search, may be null
5980     * @param remove  the String to search for and remove, may be null
5981     * @return the substring with the string removed if found,
5982     *  {@code null} if null String input
5983     * @since 2.1
5984     * @deprecated Use {@link Strings#removeStart(String, CharSequence) Strings.CS.removeStart(String, CharSequence)}
5985     */
5986    @Deprecated
5987    public static String removeStart(final String str, final String remove) {
5988        return Strings.CS.removeStart(str, remove);
5989    }
5990
5991    /**
5992     * Case-insensitive removal of a substring if it is at the beginning of a source string,
5993     * otherwise returns the source string.
5994     *
5995     * <p>A {@code null} source string will return {@code null}.
5996     * An empty ("") source string will return the empty string.
5997     * A {@code null} search string will return the source string.</p>
5998     *
5999     * <pre>
6000     * StringUtils.removeStartIgnoreCase(null, *)      = null
6001     * StringUtils.removeStartIgnoreCase("", *)        = ""
6002     * StringUtils.removeStartIgnoreCase(*, null)      = *
6003     * StringUtils.removeStartIgnoreCase("www.domain.com", "www.")   = "domain.com"
6004     * StringUtils.removeStartIgnoreCase("www.domain.com", "WWW.")   = "domain.com"
6005     * StringUtils.removeStartIgnoreCase("domain.com", "www.")       = "domain.com"
6006     * StringUtils.removeStartIgnoreCase("www.domain.com", "domain") = "www.domain.com"
6007     * StringUtils.removeStartIgnoreCase("abc", "")    = "abc"
6008     * </pre>
6009     *
6010     * @param str  the source String to search, may be null
6011     * @param remove  the String to search for (case-insensitive) and remove, may be null
6012     * @return the substring with the string removed if found,
6013     *  {@code null} if null String input
6014     * @since 2.4
6015     * @deprecated Use {@link Strings#removeStart(String, CharSequence) Strings.CI.removeStart(String, CharSequence)}
6016     */
6017    @Deprecated
6018    public static String removeStartIgnoreCase(final String str, final String remove) {
6019        return Strings.CI.removeStart(str, remove);
6020    }
6021
6022    /**
6023     * Returns padding using the specified delimiter repeated
6024     * to a given length.
6025     *
6026     * <pre>
6027     * StringUtils.repeat('e', 0)  = ""
6028     * StringUtils.repeat('e', 3)  = "eee"
6029     * StringUtils.repeat('e', -2) = ""
6030     * </pre>
6031     *
6032     * <p>Note: this method does not support padding with
6033     * <a href="https://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
6034     * as they require a pair of {@code char}s to be represented.
6035     * If you are needing to support full I18N of your applications
6036     * consider using {@link #repeat(String, int)} instead.
6037     * </p>
6038     *
6039     * @param repeat  character to repeat
6040     * @param count  number of times to repeat char, negative treated as zero
6041     * @return String with repeated character
6042     * @see #repeat(String, int)
6043     */
6044    public static String repeat(final char repeat, final int count) {
6045        if (count <= 0) {
6046            return EMPTY;
6047        }
6048        return new String(ArrayFill.fill(new char[count], repeat));
6049    }
6050
6051    /**
6052     * Repeats a String {@code repeat} times to form a
6053     * new String.
6054     *
6055     * <pre>
6056     * StringUtils.repeat(null, 2) = null
6057     * StringUtils.repeat("", 0)   = ""
6058     * StringUtils.repeat("", 2)   = ""
6059     * StringUtils.repeat("a", 3)  = "aaa"
6060     * StringUtils.repeat("ab", 2) = "abab"
6061     * StringUtils.repeat("a", -2) = ""
6062     * </pre>
6063     *
6064     * @param repeat  the String to repeat, may be null
6065     * @param count  number of times to repeat str, negative treated as zero
6066     * @return a new String consisting of the original String repeated,
6067     *  {@code null} if null String input
6068     */
6069    public static String repeat(final String repeat, final int count) {
6070        // Performance tuned for 2.0 (JDK1.4)
6071        if (repeat == null) {
6072            return null;
6073        }
6074        if (count <= 0) {
6075            return EMPTY;
6076        }
6077        final int inputLength = repeat.length();
6078        if (count == 1 || inputLength == 0) {
6079            return repeat;
6080        }
6081        if (inputLength == 1 && count <= PAD_LIMIT) {
6082            return repeat(repeat.charAt(0), count);
6083        }
6084
6085        final int outputLength = inputLength * count;
6086        switch (inputLength) {
6087            case 1 :
6088                return repeat(repeat.charAt(0), count);
6089            case 2 :
6090                final char ch0 = repeat.charAt(0);
6091                final char ch1 = repeat.charAt(1);
6092                final char[] output2 = new char[outputLength];
6093                for (int i = count * 2 - 2; i >= 0; i--, i--) {
6094                    output2[i] = ch0;
6095                    output2[i + 1] = ch1;
6096                }
6097                return new String(output2);
6098            default :
6099                final StringBuilder buf = new StringBuilder(outputLength);
6100                for (int i = 0; i < count; i++) {
6101                    buf.append(repeat);
6102                }
6103                return buf.toString();
6104        }
6105    }
6106
6107    /**
6108     * Repeats a String {@code repeat} times to form a
6109     * new String, with a String separator injected each time.
6110     *
6111     * <pre>
6112     * StringUtils.repeat(null, null, 2) = null
6113     * StringUtils.repeat(null, "x", 2)  = null
6114     * StringUtils.repeat("", null, 0)   = ""
6115     * StringUtils.repeat("", "", 2)     = ""
6116     * StringUtils.repeat("", "x", 3)    = "xx"
6117     * StringUtils.repeat("?", ", ", 3)  = "?, ?, ?"
6118     * </pre>
6119     *
6120     * @param repeat        the String to repeat, may be null
6121     * @param separator  the String to inject, may be null
6122     * @param count     number of times to repeat str, negative treated as zero
6123     * @return a new String consisting of the original String repeated,
6124     *  {@code null} if null String input
6125     * @since 2.5
6126     */
6127    public static String repeat(final String repeat, final String separator, final int count) {
6128        if (repeat == null || separator == null) {
6129            return repeat(repeat, count);
6130        }
6131        // given that repeat(String, int) is quite optimized, better to rely on it than try and splice this into it
6132        final String result = repeat(repeat + separator, count);
6133        return Strings.CS.removeEnd(result, separator);
6134    }
6135
6136    /**
6137     * Replaces all occurrences of a String within another String.
6138     *
6139     * <p>A {@code null} reference passed to this method is a no-op.</p>
6140     *
6141     * <pre>
6142     * StringUtils.replace(null, *, *)        = null
6143     * StringUtils.replace("", *, *)          = ""
6144     * StringUtils.replace("any", null, *)    = "any"
6145     * StringUtils.replace("any", *, null)    = "any"
6146     * StringUtils.replace("any", "", *)      = "any"
6147     * StringUtils.replace("aba", "a", null)  = "aba"
6148     * StringUtils.replace("aba", "a", "")    = "b"
6149     * StringUtils.replace("aba", "a", "z")   = "zbz"
6150     * </pre>
6151     *
6152     * @see #replace(String text, String searchString, String replacement, int max)
6153     * @param text  text to search and replace in, may be null
6154     * @param searchString  the String to search for, may be null
6155     * @param replacement  the String to replace it with, may be null
6156     * @return the text with any replacements processed,
6157     *  {@code null} if null String input
6158     * @deprecated Use {@link Strings#replace(String, String, String) Strings.CS.replace(String, String, String)}
6159     */
6160    @Deprecated
6161    public static String replace(final String text, final String searchString, final String replacement) {
6162        return Strings.CS.replace(text, searchString, replacement);
6163    }
6164
6165    /**
6166     * Replaces a String with another String inside a larger String,
6167     * for the first {@code max} values of the search String.
6168     *
6169     * <p>A {@code null} reference passed to this method is a no-op.</p>
6170     *
6171     * <pre>
6172     * StringUtils.replace(null, *, *, *)         = null
6173     * StringUtils.replace("", *, *, *)           = ""
6174     * StringUtils.replace("any", null, *, *)     = "any"
6175     * StringUtils.replace("any", *, null, *)     = "any"
6176     * StringUtils.replace("any", "", *, *)       = "any"
6177     * StringUtils.replace("any", *, *, 0)        = "any"
6178     * StringUtils.replace("abaa", "a", null, -1) = "abaa"
6179     * StringUtils.replace("abaa", "a", "", -1)   = "b"
6180     * StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
6181     * StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
6182     * StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
6183     * StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
6184     * </pre>
6185     *
6186     * @param text  text to search and replace in, may be null
6187     * @param searchString  the String to search for, may be null
6188     * @param replacement  the String to replace it with, may be null
6189     * @param max  maximum number of values to replace, or {@code -1} if no maximum
6190     * @return the text with any replacements processed,
6191     *  {@code null} if null String input
6192     * @deprecated Use {@link Strings#replace(String, String, String, int) Strings.CS.replace(String, String, String, int)}
6193     */
6194    @Deprecated
6195    public static String replace(final String text, final String searchString, final String replacement, final int max) {
6196        return Strings.CS.replace(text, searchString, replacement, max);
6197    }
6198
6199    /**
6200     * Replaces each substring of the text String that matches the given regular expression
6201     * with the given replacement.
6202     *
6203     * This method is a {@code null} safe equivalent to:
6204     * <ul>
6205     *  <li>{@code text.replaceAll(regex, replacement)}</li>
6206     *  <li>{@code Pattern.compile(regex).matcher(text).replaceAll(replacement)}</li>
6207     * </ul>
6208     *
6209     * <p>A {@code null} reference passed to this method is a no-op.</p>
6210     *
6211     * <p>Unlike in the {@link #replacePattern(String, String, String)} method, the {@link Pattern#DOTALL} option
6212     * is NOT automatically added.
6213     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
6214     * DOTALL is also known as single-line mode in Perl.</p>
6215     *
6216     * <pre>{@code
6217     * StringUtils.replaceAll(null, *, *)       = null
6218     * StringUtils.replaceAll("any", (String) null, *)   = "any"
6219     * StringUtils.replaceAll("any", *, null)   = "any"
6220     * StringUtils.replaceAll("", "", "zzz")    = "zzz"
6221     * StringUtils.replaceAll("", ".*", "zzz")  = "zzz"
6222     * StringUtils.replaceAll("", ".+", "zzz")  = ""
6223     * StringUtils.replaceAll("abc", "", "ZZ")  = "ZZaZZbZZcZZ"
6224     * StringUtils.replaceAll("<__>\n<__>", "<.*>", "z")      = "z\nz"
6225     * StringUtils.replaceAll("<__>\n<__>", "(?s)<.*>", "z")  = "z"
6226     * StringUtils.replaceAll("ABCabc123", "[a-z]", "_")       = "ABC___123"
6227     * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
6228     * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
6229     * StringUtils.replaceAll("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
6230     * }</pre>
6231     *
6232     * @param text  text to search and replace in, may be null
6233     * @param regex  the regular expression to which this string is to be matched
6234     * @param replacement  the string to be substituted for each match
6235     * @return  the text with any replacements processed,
6236     *              {@code null} if null String input
6237     *
6238     * @throws  java.util.regex.PatternSyntaxException
6239     *              if the regular expression's syntax is invalid
6240     *
6241     * @see #replacePattern(String, String, String)
6242     * @see String#replaceAll(String, String)
6243     * @see java.util.regex.Pattern
6244     * @see java.util.regex.Pattern#DOTALL
6245     * @since 3.5
6246     * @deprecated Moved to RegExUtils.
6247     */
6248    @Deprecated
6249    public static String replaceAll(final String text, final String regex, final String replacement) {
6250        return RegExUtils.replaceAll(text, regex, replacement);
6251    }
6252
6253    /**
6254     * Replaces all occurrences of a character in a String with another.
6255     * This is a null-safe version of {@link String#replace(char, char)}.
6256     *
6257     * <p>A {@code null} string input returns {@code null}.
6258     * An empty ("") string input returns an empty string.</p>
6259     *
6260     * <pre>
6261     * StringUtils.replaceChars(null, *, *)        = null
6262     * StringUtils.replaceChars("", *, *)          = ""
6263     * StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
6264     * StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
6265     * </pre>
6266     *
6267     * @param str  String to replace characters in, may be null
6268     * @param searchChar  the character to search for, may be null
6269     * @param replaceChar  the character to replace, may be null
6270     * @return modified String, {@code null} if null string input
6271     * @since 2.0
6272     */
6273    public static String replaceChars(final String str, final char searchChar, final char replaceChar) {
6274        if (str == null) {
6275            return null;
6276        }
6277        return str.replace(searchChar, replaceChar);
6278    }
6279
6280    /**
6281     * Replaces multiple characters in a String in one go.
6282     * This method can also be used to delete characters.
6283     *
6284     * <p>For example:<br>
6285     * {@code replaceChars(&quot;hello&quot;, &quot;ho&quot;, &quot;jy&quot;) = jelly}.</p>
6286     *
6287     * <p>A {@code null} string input returns {@code null}.
6288     * An empty ("") string input returns an empty string.
6289     * A null or empty set of search characters returns the input string.</p>
6290     *
6291     * <p>The length of the search characters should normally equal the length
6292     * of the replace characters.
6293     * If the search characters is longer, then the extra search characters
6294     * are deleted.
6295     * If the search characters is shorter, then the extra replace characters
6296     * are ignored.</p>
6297     *
6298     * <pre>
6299     * StringUtils.replaceChars(null, *, *)           = null
6300     * StringUtils.replaceChars("", *, *)             = ""
6301     * StringUtils.replaceChars("abc", null, *)       = "abc"
6302     * StringUtils.replaceChars("abc", "", *)         = "abc"
6303     * StringUtils.replaceChars("abc", "b", null)     = "ac"
6304     * StringUtils.replaceChars("abc", "b", "")       = "ac"
6305     * StringUtils.replaceChars("abcba", "bc", "yz")  = "ayzya"
6306     * StringUtils.replaceChars("abcba", "bc", "y")   = "ayya"
6307     * StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
6308     * </pre>
6309     *
6310     * @param str  String to replace characters in, may be null
6311     * @param searchChars  a set of characters to search for, may be null
6312     * @param replaceChars  a set of characters to replace, may be null
6313     * @return modified String, {@code null} if null string input
6314     * @since 2.0
6315     */
6316    public static String replaceChars(final String str, final String searchChars, String replaceChars) {
6317        if (isEmpty(str) || isEmpty(searchChars)) {
6318            return str;
6319        }
6320        replaceChars = ObjectUtils.toString(replaceChars);
6321        boolean modified = false;
6322        final int replaceCharsLength = replaceChars.length();
6323        final int strLength = str.length();
6324        final StringBuilder buf = new StringBuilder(strLength);
6325        for (int i = 0; i < strLength; i++) {
6326            final char ch = str.charAt(i);
6327            final int index = searchChars.indexOf(ch);
6328            if (index >= 0) {
6329                modified = true;
6330                if (index < replaceCharsLength) {
6331                    buf.append(replaceChars.charAt(index));
6332                }
6333            } else {
6334                buf.append(ch);
6335            }
6336        }
6337        if (modified) {
6338            return buf.toString();
6339        }
6340        return str;
6341    }
6342
6343    /**
6344     * Replaces all occurrences of Strings within another String.
6345     *
6346     * <p>
6347     * A {@code null} reference passed to this method is a no-op, or if
6348     * any "search string" or "string to replace" is null, that replace will be
6349     * ignored. This will not repeat. For repeating replaces, call the
6350     * overloaded method.
6351     * </p>
6352     *
6353     * <pre>
6354     *  StringUtils.replaceEach(null, *, *)        = null
6355     *  StringUtils.replaceEach("", *, *)          = ""
6356     *  StringUtils.replaceEach("aba", null, null) = "aba"
6357     *  StringUtils.replaceEach("aba", new String[0], null) = "aba"
6358     *  StringUtils.replaceEach("aba", null, new String[0]) = "aba"
6359     *  StringUtils.replaceEach("aba", new String[]{"a"}, null)  = "aba"
6360     *  StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""})  = "b"
6361     *  StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"})  = "aba"
6362     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"})  = "wcte"
6363     *  (example of how it does not repeat)
6364     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"})  = "dcte"
6365     * </pre>
6366     *
6367     * @param text
6368     *            text to search and replace in, no-op if null
6369     * @param searchList
6370     *            the Strings to search for, no-op if null
6371     * @param replacementList
6372     *            the Strings to replace them with, no-op if null
6373     * @return the text with any replacements processed, {@code null} if
6374     *         null String input
6375     * @throws IllegalArgumentException
6376     *             if the lengths of the arrays are not the same (null is ok,
6377     *             and/or size 0)
6378     * @since 2.4
6379     */
6380    public static String replaceEach(final String text, final String[] searchList, final String[] replacementList) {
6381        return replaceEach(text, searchList, replacementList, false, 0);
6382    }
6383
6384    /**
6385     * Replace all occurrences of Strings within another String.
6386     * This is a private recursive helper method for {@link #replaceEachRepeatedly(String, String[], String[])} and
6387     * {@link #replaceEach(String, String[], String[])}
6388     *
6389     * <p>
6390     * A {@code null} reference passed to this method is a no-op, or if
6391     * any "search string" or "string to replace" is null, that replace will be
6392     * ignored.
6393     * </p>
6394     *
6395     * <pre>
6396     *  StringUtils.replaceEach(null, *, *, *, *) = null
6397     *  StringUtils.replaceEach("", *, *, *, *) = ""
6398     *  StringUtils.replaceEach("aba", null, null, *, *) = "aba"
6399     *  StringUtils.replaceEach("aba", new String[0], null, *, *) = "aba"
6400     *  StringUtils.replaceEach("aba", null, new String[0], *, *) = "aba"
6401     *  StringUtils.replaceEach("aba", new String[]{"a"}, null, *, *) = "aba"
6402     *  StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}, *, >=0) = "b"
6403     *  StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}, *, >=0) = "aba"
6404     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}, *, >=0) = "wcte"
6405     *  (example of how it repeats)
6406     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, false, >=0) = "dcte"
6407     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, true, >=2) = "tcte"
6408     *  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, *, *) = IllegalStateException
6409     * </pre>
6410     *
6411     * @param text
6412     *            text to search and replace in, no-op if null
6413     * @param searchList
6414     *            the Strings to search for, no-op if null
6415     * @param replacementList
6416     *            the Strings to replace them with, no-op if null
6417     * @param repeat if true, then replace repeatedly
6418     *       until there are no more possible replacements or timeToLive < 0
6419     * @param timeToLive
6420     *            if less than 0 then there is a circular reference and endless
6421     *            loop
6422     * @return the text with any replacements processed, {@code null} if
6423     *         null String input
6424     * @throws IllegalStateException
6425     *             if the search is repeating and there is an endless loop due
6426     *             to outputs of one being inputs to another
6427     * @throws IllegalArgumentException
6428     *             if the lengths of the arrays are not the same (null is ok,
6429     *             and/or size 0)
6430     * @since 2.4
6431     */
6432    private static String replaceEach(
6433            final String text, final String[] searchList, final String[] replacementList, final boolean repeat, final int timeToLive) {
6434
6435        // mchyzer Performance note: This creates very few new objects (one major goal)
6436        // let me know if there are performance requests, we can create a harness to measure
6437        if (isEmpty(text) || ArrayUtils.isEmpty(searchList) || ArrayUtils.isEmpty(replacementList)) {
6438            return text;
6439        }
6440
6441        // if recursing, this shouldn't be less than 0
6442        if (timeToLive < 0) {
6443            throw new IllegalStateException("Aborting to protect against StackOverflowError - " +
6444                "output of one loop is the input of another");
6445        }
6446
6447        final int searchLength = searchList.length;
6448        final int replacementLength = replacementList.length;
6449
6450        // make sure lengths are ok, these need to be equal
6451        if (searchLength != replacementLength) {
6452            throw new IllegalArgumentException("Search and Replace array lengths don't match: "
6453                + searchLength
6454                + " vs "
6455                + replacementLength);
6456        }
6457
6458        // keep track of which still have matches
6459        final boolean[] noMoreMatchesForReplIndex = new boolean[searchLength];
6460
6461        // index on index that the match was found
6462        int textIndex = -1;
6463        int replaceIndex = -1;
6464        int tempIndex;
6465
6466        // index of replace array that will replace the search string found
6467        // NOTE: logic duplicated below START
6468        for (int i = 0; i < searchLength; i++) {
6469            if (noMoreMatchesForReplIndex[i] || isEmpty(searchList[i]) || replacementList[i] == null) {
6470                continue;
6471            }
6472            tempIndex = text.indexOf(searchList[i]);
6473
6474            // see if we need to keep searching for this
6475            if (tempIndex == -1) {
6476                noMoreMatchesForReplIndex[i] = true;
6477            } else if (textIndex == -1 || tempIndex < textIndex) {
6478                textIndex = tempIndex;
6479                replaceIndex = i;
6480            }
6481        }
6482        // NOTE: logic mostly below END
6483
6484        // no search strings found, we are done
6485        if (textIndex == -1) {
6486            return text;
6487        }
6488
6489        int start = 0;
6490
6491        // get a good guess on the size of the result buffer so it doesn't have to double if it goes over a bit
6492        int increase = 0;
6493
6494        // count the replacement text elements that are larger than their corresponding text being replaced
6495        for (int i = 0; i < searchList.length; i++) {
6496            if (searchList[i] == null || replacementList[i] == null) {
6497                continue;
6498            }
6499            final int greater = replacementList[i].length() - searchList[i].length();
6500            if (greater > 0) {
6501                increase += 3 * greater; // assume 3 matches
6502            }
6503        }
6504        // have upper-bound at 20% increase, then let Java take over
6505        increase = Math.min(increase, text.length() / 5);
6506
6507        final StringBuilder buf = new StringBuilder(text.length() + increase);
6508
6509        while (textIndex != -1) {
6510
6511            for (int i = start; i < textIndex; i++) {
6512                buf.append(text.charAt(i));
6513            }
6514            buf.append(replacementList[replaceIndex]);
6515
6516            start = textIndex + searchList[replaceIndex].length();
6517
6518            textIndex = -1;
6519            replaceIndex = -1;
6520            // find the next earliest match
6521            // NOTE: logic mostly duplicated above START
6522            for (int i = 0; i < searchLength; i++) {
6523                if (noMoreMatchesForReplIndex[i] || isEmpty(searchList[i]) || replacementList[i] == null) {
6524                    continue;
6525                }
6526                tempIndex = text.indexOf(searchList[i], start);
6527
6528                // see if we need to keep searching for this
6529                if (tempIndex == -1) {
6530                    noMoreMatchesForReplIndex[i] = true;
6531                } else if (textIndex == -1 || tempIndex < textIndex) {
6532                    textIndex = tempIndex;
6533                    replaceIndex = i;
6534                }
6535            }
6536            // NOTE: logic duplicated above END
6537
6538        }
6539        final int textLength = text.length();
6540        for (int i = start; i < textLength; i++) {
6541            buf.append(text.charAt(i));
6542        }
6543        final String result = buf.toString();
6544        if (!repeat) {
6545            return result;
6546        }
6547
6548        return replaceEach(result, searchList, replacementList, repeat, timeToLive - 1);
6549    }
6550
6551    /**
6552     * Replaces all occurrences of Strings within another String.
6553     *
6554     * <p>
6555     * A {@code null} reference passed to this method is a no-op, or if
6556     * any "search string" or "string to replace" is null, that replace will be
6557     * ignored.
6558     * </p>
6559     *
6560     * <pre>
6561     *  StringUtils.replaceEachRepeatedly(null, *, *) = null
6562     *  StringUtils.replaceEachRepeatedly("", *, *) = ""
6563     *  StringUtils.replaceEachRepeatedly("aba", null, null) = "aba"
6564     *  StringUtils.replaceEachRepeatedly("aba", new String[0], null) = "aba"
6565     *  StringUtils.replaceEachRepeatedly("aba", null, new String[0]) = "aba"
6566     *  StringUtils.replaceEachRepeatedly("aba", new String[]{"a"}, null) = "aba"
6567     *  StringUtils.replaceEachRepeatedly("aba", new String[]{"a"}, new String[]{""}) = "b"
6568     *  StringUtils.replaceEachRepeatedly("aba", new String[]{null}, new String[]{"a"}) = "aba"
6569     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}) = "wcte"
6570     *  (example of how it repeats)
6571     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}) = "tcte"
6572     *  StringUtils.replaceEachRepeatedly("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}) = IllegalStateException
6573     * </pre>
6574     *
6575     * @param text
6576     *            text to search and replace in, no-op if null
6577     * @param searchList
6578     *            the Strings to search for, no-op if null
6579     * @param replacementList
6580     *            the Strings to replace them with, no-op if null
6581     * @return the text with any replacements processed, {@code null} if
6582     *         null String input
6583     * @throws IllegalStateException
6584     *             if the search is repeating and there is an endless loop due
6585     *             to outputs of one being inputs to another
6586     * @throws IllegalArgumentException
6587     *             if the lengths of the arrays are not the same (null is ok,
6588     *             and/or size 0)
6589     * @since 2.4
6590     */
6591    public static String replaceEachRepeatedly(final String text, final String[] searchList, final String[] replacementList) {
6592        final int timeToLive = Math.max(ArrayUtils.getLength(searchList), DEFAULT_TTL);
6593        return replaceEach(text, searchList, replacementList, true, timeToLive);
6594    }
6595
6596    /**
6597     * Replaces the first substring of the text string that matches the given regular expression
6598     * with the given replacement.
6599     *
6600     * This method is a {@code null} safe equivalent to:
6601     * <ul>
6602     *  <li>{@code text.replaceFirst(regex, replacement)}</li>
6603     *  <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(replacement)}</li>
6604     * </ul>
6605     *
6606     * <p>A {@code null} reference passed to this method is a no-op.</p>
6607     *
6608     * <p>The {@link Pattern#DOTALL} option is NOT automatically added.
6609     * To use the DOTALL option prepend {@code "(?s)"} to the regex.
6610     * DOTALL is also known as single-line mode in Perl.</p>
6611     *
6612     * <pre>{@code
6613     * StringUtils.replaceFirst(null, *, *)       = null
6614     * StringUtils.replaceFirst("any", (String) null, *)   = "any"
6615     * StringUtils.replaceFirst("any", *, null)   = "any"
6616     * StringUtils.replaceFirst("", "", "zzz")    = "zzz"
6617     * StringUtils.replaceFirst("", ".*", "zzz")  = "zzz"
6618     * StringUtils.replaceFirst("", ".+", "zzz")  = ""
6619     * StringUtils.replaceFirst("abc", "", "ZZ")  = "ZZabc"
6620     * StringUtils.replaceFirst("<__>\n<__>", "<.*>", "z")      = "z\n<__>"
6621     * StringUtils.replaceFirst("<__>\n<__>", "(?s)<.*>", "z")  = "z"
6622     * StringUtils.replaceFirst("ABCabc123", "[a-z]", "_")          = "ABC_bc123"
6623     * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "_")  = "ABC_123abc"
6624     * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "")   = "ABC123abc"
6625     * StringUtils.replaceFirst("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum  dolor   sit"
6626     * }</pre>
6627     *
6628     * @param text  text to search and replace in, may be null
6629     * @param regex  the regular expression to which this string is to be matched
6630     * @param replacement  the string to be substituted for the first match
6631     * @return  the text with the first replacement processed,
6632     *              {@code null} if null String input
6633     *
6634     * @throws  java.util.regex.PatternSyntaxException
6635     *              if the regular expression's syntax is invalid
6636     *
6637     * @see String#replaceFirst(String, String)
6638     * @see java.util.regex.Pattern
6639     * @see java.util.regex.Pattern#DOTALL
6640     * @since 3.5
6641     * @deprecated Moved to RegExUtils.
6642     */
6643    @Deprecated
6644    public static String replaceFirst(final String text, final String regex, final String replacement) {
6645        return RegExUtils.replaceFirst(text, regex, replacement);
6646    }
6647
6648    /**
6649     * Case insensitively replaces all occurrences of a String within another String.
6650     *
6651     * <p>A {@code null} reference passed to this method is a no-op.</p>
6652     *
6653     * <pre>
6654     * StringUtils.replaceIgnoreCase(null, *, *)        = null
6655     * StringUtils.replaceIgnoreCase("", *, *)          = ""
6656     * StringUtils.replaceIgnoreCase("any", null, *)    = "any"
6657     * StringUtils.replaceIgnoreCase("any", *, null)    = "any"
6658     * StringUtils.replaceIgnoreCase("any", "", *)      = "any"
6659     * StringUtils.replaceIgnoreCase("aba", "a", null)  = "aba"
6660     * StringUtils.replaceIgnoreCase("abA", "A", "")    = "b"
6661     * StringUtils.replaceIgnoreCase("aba", "A", "z")   = "zbz"
6662     * </pre>
6663     *
6664     * @see #replaceIgnoreCase(String text, String searchString, String replacement, int max)
6665     * @param text  text to search and replace in, may be null
6666     * @param searchString  the String to search for (case-insensitive), may be null
6667     * @param replacement  the String to replace it with, may be null
6668     * @return the text with any replacements processed,
6669     *  {@code null} if null String input
6670     * @since 3.5
6671     * @deprecated Use {@link Strings#replace(String, String, String) Strings.CI.replace(String, String, String)}
6672     */
6673    @Deprecated
6674     public static String replaceIgnoreCase(final String text, final String searchString, final String replacement) {
6675         return Strings.CI.replace(text, searchString, replacement);
6676     }
6677
6678    /**
6679     * Case insensitively replaces a String with another String inside a larger String,
6680     * for the first {@code max} values of the search String.
6681     *
6682     * <p>A {@code null} reference passed to this method is a no-op.</p>
6683     *
6684     * <pre>
6685     * StringUtils.replaceIgnoreCase(null, *, *, *)         = null
6686     * StringUtils.replaceIgnoreCase("", *, *, *)           = ""
6687     * StringUtils.replaceIgnoreCase("any", null, *, *)     = "any"
6688     * StringUtils.replaceIgnoreCase("any", *, null, *)     = "any"
6689     * StringUtils.replaceIgnoreCase("any", "", *, *)       = "any"
6690     * StringUtils.replaceIgnoreCase("any", *, *, 0)        = "any"
6691     * StringUtils.replaceIgnoreCase("abaa", "a", null, -1) = "abaa"
6692     * StringUtils.replaceIgnoreCase("abaa", "a", "", -1)   = "b"
6693     * StringUtils.replaceIgnoreCase("abaa", "a", "z", 0)   = "abaa"
6694     * StringUtils.replaceIgnoreCase("abaa", "A", "z", 1)   = "zbaa"
6695     * StringUtils.replaceIgnoreCase("abAa", "a", "z", 2)   = "zbza"
6696     * StringUtils.replaceIgnoreCase("abAa", "a", "z", -1)  = "zbzz"
6697     * </pre>
6698     *
6699     * @param text  text to search and replace in, may be null
6700     * @param searchString  the String to search for (case-insensitive), may be null
6701     * @param replacement  the String to replace it with, may be null
6702     * @param max  maximum number of values to replace, or {@code -1} if no maximum
6703     * @return the text with any replacements processed,
6704     *  {@code null} if null String input
6705     * @since 3.5
6706     * @deprecated Use {@link Strings#replace(String, String, String, int) Strings.CI.replace(String, String, String, int)}
6707     */
6708    @Deprecated
6709    public static String replaceIgnoreCase(final String text, final String searchString, final String replacement, final int max) {
6710        return Strings.CI.replace(text, searchString, replacement, max);
6711    }
6712
6713    /**
6714     * Replaces a String with another String inside a larger String, once.
6715     *
6716     * <p>A {@code null} reference passed to this method is a no-op.</p>
6717     *
6718     * <pre>
6719     * StringUtils.replaceOnce(null, *, *)        = null
6720     * StringUtils.replaceOnce("", *, *)          = ""
6721     * StringUtils.replaceOnce("any", null, *)    = "any"
6722     * StringUtils.replaceOnce("any", *, null)    = "any"
6723     * StringUtils.replaceOnce("any", "", *)      = "any"
6724     * StringUtils.replaceOnce("aba", "a", null)  = "aba"
6725     * StringUtils.replaceOnce("aba", "a", "")    = "ba"
6726     * StringUtils.replaceOnce("aba", "a", "z")   = "zba"
6727     * </pre>
6728     *
6729     * @see #replace(String text, String searchString, String replacement, int max)
6730     * @param text  text to search and replace in, may be null
6731     * @param searchString  the String to search for, may be null
6732     * @param replacement  the String to replace with, may be null
6733     * @return the text with any replacements processed,
6734     *  {@code null} if null String input
6735     * @deprecated Use {@link Strings#replaceOnce(String, String, String) Strings.CS.replaceOnce(String, String, String)}
6736     */
6737    @Deprecated
6738    public static String replaceOnce(final String text, final String searchString, final String replacement) {
6739        return Strings.CS.replaceOnce(text, searchString, replacement);
6740    }
6741
6742    /**
6743     * Case insensitively replaces a String with another String inside a larger String, once.
6744     *
6745     * <p>A {@code null} reference passed to this method is a no-op.</p>
6746     *
6747     * <pre>
6748     * StringUtils.replaceOnceIgnoreCase(null, *, *)        = null
6749     * StringUtils.replaceOnceIgnoreCase("", *, *)          = ""
6750     * StringUtils.replaceOnceIgnoreCase("any", null, *)    = "any"
6751     * StringUtils.replaceOnceIgnoreCase("any", *, null)    = "any"
6752     * StringUtils.replaceOnceIgnoreCase("any", "", *)      = "any"
6753     * StringUtils.replaceOnceIgnoreCase("aba", "a", null)  = "aba"
6754     * StringUtils.replaceOnceIgnoreCase("aba", "a", "")    = "ba"
6755     * StringUtils.replaceOnceIgnoreCase("aba", "a", "z")   = "zba"
6756     * StringUtils.replaceOnceIgnoreCase("FoOFoofoo", "foo", "") = "Foofoo"
6757     * </pre>
6758     *
6759     * @see #replaceIgnoreCase(String text, String searchString, String replacement, int max)
6760     * @param text  text to search and replace in, may be null
6761     * @param searchString  the String to search for (case-insensitive), may be null
6762     * @param replacement  the String to replace with, may be null
6763     * @return the text with any replacements processed,
6764     *  {@code null} if null String input
6765     * @since 3.5
6766     * @deprecated Use {@link Strings#replaceOnce(String, String, String) Strings.CI.replaceOnce(String, String, String)}
6767     */
6768    @Deprecated
6769    public static String replaceOnceIgnoreCase(final String text, final String searchString, final String replacement) {
6770        return Strings.CI.replaceOnce(text, searchString, replacement);
6771    }
6772
6773    /**
6774     * Replaces each substring of the source String that matches the given regular expression with the given
6775     * replacement using the {@link Pattern#DOTALL} option. DOTALL is also known as single-line mode in Perl.
6776     *
6777     * This call is a {@code null} safe equivalent to:
6778     * <ul>
6779     * <li>{@code source.replaceAll(&quot;(?s)&quot; + regex, replacement)}</li>
6780     * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(source).replaceAll(replacement)}</li>
6781     * </ul>
6782     *
6783     * <p>A {@code null} reference passed to this method is a no-op.</p>
6784     *
6785     * <pre>{@code
6786     * StringUtils.replacePattern(null, *, *)       = null
6787     * StringUtils.replacePattern("any", (String) null, *)   = "any"
6788     * StringUtils.replacePattern("any", *, null)   = "any"
6789     * StringUtils.replacePattern("", "", "zzz")    = "zzz"
6790     * StringUtils.replacePattern("", ".*", "zzz")  = "zzz"
6791     * StringUtils.replacePattern("", ".+", "zzz")  = ""
6792     * StringUtils.replacePattern("<__>\n<__>", "<.*>", "z")       = "z"
6793     * StringUtils.replacePattern("ABCabc123", "[a-z]", "_")       = "ABC___123"
6794     * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
6795     * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
6796     * StringUtils.replacePattern("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
6797     * }</pre>
6798     *
6799     * @param source
6800     *            the source string
6801     * @param regex
6802     *            the regular expression to which this string is to be matched
6803     * @param replacement
6804     *            the string to be substituted for each match
6805     * @return The resulting {@link String}
6806     * @see #replaceAll(String, String, String)
6807     * @see String#replaceAll(String, String)
6808     * @see Pattern#DOTALL
6809     * @since 3.2
6810     * @since 3.5 Changed {@code null} reference passed to this method is a no-op.
6811     * @deprecated Moved to RegExUtils.
6812     */
6813    @Deprecated
6814    public static String replacePattern(final String source, final String regex, final String replacement) {
6815        return RegExUtils.replacePattern(source, regex, replacement);
6816    }
6817
6818    /**
6819     * Reverses a String as per {@link StringBuilder#reverse()}.
6820     *
6821     * <p>A {@code null} String returns {@code null}.</p>
6822     *
6823     * <pre>
6824     * StringUtils.reverse(null)  = null
6825     * StringUtils.reverse("")    = ""
6826     * StringUtils.reverse("bat") = "tab"
6827     * </pre>
6828     *
6829     * @param str  the String to reverse, may be null
6830     * @return the reversed String, {@code null} if null String input
6831     */
6832    public static String reverse(final String str) {
6833        if (str == null) {
6834            return null;
6835        }
6836        return new StringBuilder(str).reverse().toString();
6837    }
6838
6839    /**
6840     * Reverses a String that is delimited by a specific character.
6841     *
6842     * <p>The Strings between the delimiters are not reversed.
6843     * Thus java.lang.String becomes String.lang.java (if the delimiter
6844     * is {@code '.'}).</p>
6845     *
6846     * <pre>
6847     * StringUtils.reverseDelimited(null, *)      = null
6848     * StringUtils.reverseDelimited("", *)        = ""
6849     * StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
6850     * StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"
6851     * </pre>
6852     *
6853     * @param str  the String to reverse, may be null
6854     * @param separatorChar  the separator character to use
6855     * @return the reversed String, {@code null} if null String input
6856     * @since 2.0
6857     */
6858    public static String reverseDelimited(final String str, final char separatorChar) {
6859        final String[] strs = split(str, separatorChar);
6860        ArrayUtils.reverse(strs);
6861        return join(strs, separatorChar);
6862    }
6863
6864    /**
6865     * Gets the rightmost {@code len} characters of a String.
6866     *
6867     * <p>If {@code len} characters are not available, or the String
6868     * is {@code null}, the String will be returned without an
6869     * an exception. An empty String is returned if len is negative.</p>
6870     *
6871     * <pre>
6872     * StringUtils.right(null, *)    = null
6873     * StringUtils.right(*, -ve)     = ""
6874     * StringUtils.right("", *)      = ""
6875     * StringUtils.right("abc", 0)   = ""
6876     * StringUtils.right("abc", 2)   = "bc"
6877     * StringUtils.right("abc", 4)   = "abc"
6878     * </pre>
6879     *
6880     * @param str  the String to get the rightmost characters from, may be null
6881     * @param len  the length of the required String
6882     * @return the rightmost characters, {@code null} if null String input
6883     */
6884    public static String right(final String str, final int len) {
6885        if (str == null) {
6886            return null;
6887        }
6888        if (len < 0) {
6889            return EMPTY;
6890        }
6891        if (str.length() <= len) {
6892            return str;
6893        }
6894        return str.substring(str.length() - len);
6895    }
6896
6897    /**
6898     * Right pad a String with spaces (' ').
6899     *
6900     * <p>The String is padded to the size of {@code size}.</p>
6901     *
6902     * <pre>
6903     * StringUtils.rightPad(null, *)   = null
6904     * StringUtils.rightPad("", 3)     = "   "
6905     * StringUtils.rightPad("bat", 3)  = "bat"
6906     * StringUtils.rightPad("bat", 5)  = "bat  "
6907     * StringUtils.rightPad("bat", 1)  = "bat"
6908     * StringUtils.rightPad("bat", -1) = "bat"
6909     * </pre>
6910     *
6911     * @param str  the String to pad out, may be null
6912     * @param size  the size to pad to
6913     * @return right padded String or original String if no padding is necessary,
6914     *  {@code null} if null String input
6915     */
6916    public static String rightPad(final String str, final int size) {
6917        return rightPad(str, size, ' ');
6918    }
6919
6920    /**
6921     * Right pad a String with a specified character.
6922     *
6923     * <p>The String is padded to the size of {@code size}.</p>
6924     *
6925     * <pre>
6926     * StringUtils.rightPad(null, *, *)     = null
6927     * StringUtils.rightPad("", 3, 'z')     = "zzz"
6928     * StringUtils.rightPad("bat", 3, 'z')  = "bat"
6929     * StringUtils.rightPad("bat", 5, 'z')  = "batzz"
6930     * StringUtils.rightPad("bat", 1, 'z')  = "bat"
6931     * StringUtils.rightPad("bat", -1, 'z') = "bat"
6932     * </pre>
6933     *
6934     * @param str  the String to pad out, may be null
6935     * @param size  the size to pad to
6936     * @param padChar  the character to pad with
6937     * @return right padded String or original String if no padding is necessary,
6938     *  {@code null} if null String input
6939     * @since 2.0
6940     */
6941    public static String rightPad(final String str, final int size, final char padChar) {
6942        if (str == null) {
6943            return null;
6944        }
6945        final int pads = size - str.length();
6946        if (pads <= 0) {
6947            return str; // returns original String when possible
6948        }
6949        if (pads > PAD_LIMIT) {
6950            return rightPad(str, size, String.valueOf(padChar));
6951        }
6952        return str.concat(repeat(padChar, pads));
6953    }
6954
6955    /**
6956     * Right pad a String with a specified String.
6957     *
6958     * <p>The String is padded to the size of {@code size}.</p>
6959     *
6960     * <pre>
6961     * StringUtils.rightPad(null, *, *)      = null
6962     * StringUtils.rightPad("", 3, "z")      = "zzz"
6963     * StringUtils.rightPad("bat", 3, "yz")  = "bat"
6964     * StringUtils.rightPad("bat", 5, "yz")  = "batyz"
6965     * StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
6966     * StringUtils.rightPad("bat", 1, "yz")  = "bat"
6967     * StringUtils.rightPad("bat", -1, "yz") = "bat"
6968     * StringUtils.rightPad("bat", 5, null)  = "bat  "
6969     * StringUtils.rightPad("bat", 5, "")    = "bat  "
6970     * </pre>
6971     *
6972     * @param str  the String to pad out, may be null
6973     * @param size  the size to pad to
6974     * @param padStr  the String to pad with, null or empty treated as single space
6975     * @return right padded String or original String if no padding is necessary,
6976     *  {@code null} if null String input
6977     */
6978    public static String rightPad(final String str, final int size, String padStr) {
6979        if (str == null) {
6980            return null;
6981        }
6982        if (isEmpty(padStr)) {
6983            padStr = SPACE;
6984        }
6985        final int padLen = padStr.length();
6986        final int strLen = str.length();
6987        final int pads = size - strLen;
6988        if (pads <= 0) {
6989            return str; // returns original String when possible
6990        }
6991        if (padLen == 1 && pads <= PAD_LIMIT) {
6992            return rightPad(str, size, padStr.charAt(0));
6993        }
6994
6995        if (pads == padLen) {
6996            return str.concat(padStr);
6997        }
6998        if (pads < padLen) {
6999            return str.concat(padStr.substring(0, pads));
7000        }
7001        final char[] padding = new char[pads];
7002        final char[] padChars = padStr.toCharArray();
7003        for (int i = 0; i < pads; i++) {
7004            padding[i] = padChars[i % padLen];
7005        }
7006        return str.concat(new String(padding));
7007    }
7008
7009    /**
7010     * Rotate (circular shift) a String of {@code shift} characters.
7011     * <ul>
7012     *  <li>If {@code shift > 0}, right circular shift (ex : ABCDEF =&gt; FABCDE)</li>
7013     *  <li>If {@code shift < 0}, left circular shift (ex : ABCDEF =&gt; BCDEFA)</li>
7014     * </ul>
7015     *
7016     * <pre>
7017     * StringUtils.rotate(null, *)        = null
7018     * StringUtils.rotate("", *)          = ""
7019     * StringUtils.rotate("abcdefg", 0)   = "abcdefg"
7020     * StringUtils.rotate("abcdefg", 2)   = "fgabcde"
7021     * StringUtils.rotate("abcdefg", -2)  = "cdefgab"
7022     * StringUtils.rotate("abcdefg", 7)   = "abcdefg"
7023     * StringUtils.rotate("abcdefg", -7)  = "abcdefg"
7024     * StringUtils.rotate("abcdefg", 9)   = "fgabcde"
7025     * StringUtils.rotate("abcdefg", -9)  = "cdefgab"
7026     * </pre>
7027     *
7028     * @param str  the String to rotate, may be null
7029     * @param shift  number of time to shift (positive : right shift, negative : left shift)
7030     * @return the rotated String,
7031     *          or the original String if {@code shift == 0},
7032     *          or {@code null} if null String input
7033     * @since 3.5
7034     */
7035    public static String rotate(final String str, final int shift) {
7036        if (str == null) {
7037            return null;
7038        }
7039
7040        final int strLen = str.length();
7041        if (shift == 0 || strLen == 0 || shift % strLen == 0) {
7042            return str;
7043        }
7044
7045        final StringBuilder builder = new StringBuilder(strLen);
7046        final int offset = - (shift % strLen);
7047        builder.append(substring(str, offset));
7048        builder.append(substring(str, 0, offset));
7049        return builder.toString();
7050    }
7051
7052    /**
7053     * Splits the provided text into an array, using whitespace as the
7054     * separator.
7055     * Whitespace is defined by {@link Character#isWhitespace(char)}.
7056     *
7057     * <p>The separator is not included in the returned String array.
7058     * Adjacent separators are treated as one separator.
7059     * For more control over the split use the StrTokenizer class.</p>
7060     *
7061     * <p>A {@code null} input String returns {@code null}.</p>
7062     *
7063     * <pre>
7064     * StringUtils.split(null)       = null
7065     * StringUtils.split("")         = []
7066     * StringUtils.split("abc def")  = ["abc", "def"]
7067     * StringUtils.split("abc  def") = ["abc", "def"]
7068     * StringUtils.split(" abc ")    = ["abc"]
7069     * </pre>
7070     *
7071     * @param str  the String to parse, may be null
7072     * @return an array of parsed Strings, {@code null} if null String input
7073     */
7074    public static String[] split(final String str) {
7075        return split(str, null, -1);
7076    }
7077
7078    /**
7079     * Splits the provided text into an array, separator specified.
7080     * This is an alternative to using StringTokenizer.
7081     *
7082     * <p>The separator is not included in the returned String array.
7083     * Adjacent separators are treated as one separator.
7084     * For more control over the split use the StrTokenizer class.</p>
7085     *
7086     * <p>A {@code null} input String returns {@code null}.</p>
7087     *
7088     * <pre>
7089     * StringUtils.split(null, *)         = null
7090     * StringUtils.split("", *)           = []
7091     * StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
7092     * StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
7093     * StringUtils.split("a:b:c", '.')    = ["a:b:c"]
7094     * StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
7095     * </pre>
7096     *
7097     * @param str  the String to parse, may be null
7098     * @param separatorChar  the character used as the delimiter
7099     * @return an array of parsed Strings, {@code null} if null String input
7100     * @since 2.0
7101     */
7102    public static String[] split(final String str, final char separatorChar) {
7103        return splitWorker(str, separatorChar, false);
7104    }
7105
7106    /**
7107     * Splits the provided text into an array, separators specified.
7108     * This is an alternative to using StringTokenizer.
7109     *
7110     * <p>The separator is not included in the returned String array.
7111     * Adjacent separators are treated as one separator.
7112     * For more control over the split use the StrTokenizer class.</p>
7113     *
7114     * <p>A {@code null} input String returns {@code null}.
7115     * A {@code null} separatorChars splits on whitespace.</p>
7116     *
7117     * <pre>
7118     * StringUtils.split(null, *)         = null
7119     * StringUtils.split("", *)           = []
7120     * StringUtils.split("abc def", null) = ["abc", "def"]
7121     * StringUtils.split("abc def", " ")  = ["abc", "def"]
7122     * StringUtils.split("abc  def", " ") = ["abc", "def"]
7123     * StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
7124     * </pre>
7125     *
7126     * @param str  the String to parse, may be null
7127     * @param separatorChars  the characters used as the delimiters,
7128     *  {@code null} splits on whitespace
7129     * @return an array of parsed Strings, {@code null} if null String input
7130     */
7131    public static String[] split(final String str, final String separatorChars) {
7132        return splitWorker(str, separatorChars, -1, false);
7133    }
7134
7135    /**
7136     * Splits the provided text into an array with a maximum length,
7137     * separators specified.
7138     *
7139     * <p>The separator is not included in the returned String array.
7140     * Adjacent separators are treated as one separator.</p>
7141     *
7142     * <p>A {@code null} input String returns {@code null}.
7143     * A {@code null} separatorChars splits on whitespace.</p>
7144     *
7145     * <p>If more than {@code max} delimited substrings are found, the last
7146     * returned string includes all characters after the first {@code max - 1}
7147     * returned strings (including separator characters).</p>
7148     *
7149     * <pre>
7150     * StringUtils.split(null, *, *)            = null
7151     * StringUtils.split("", *, *)              = []
7152     * StringUtils.split("ab cd ef", null, 0)   = ["ab", "cd", "ef"]
7153     * StringUtils.split("ab   cd ef", null, 0) = ["ab", "cd", "ef"]
7154     * StringUtils.split("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
7155     * StringUtils.split("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
7156     * </pre>
7157     *
7158     * @param str  the String to parse, may be null
7159     * @param separatorChars  the characters used as the delimiters,
7160     *  {@code null} splits on whitespace
7161     * @param max  the maximum number of elements to include in the
7162     *  array. A zero or negative value implies no limit
7163     * @return an array of parsed Strings, {@code null} if null String input
7164     */
7165    public static String[] split(final String str, final String separatorChars, final int max) {
7166        return splitWorker(str, separatorChars, max, false);
7167    }
7168
7169    /**
7170     * Splits a String by Character type as returned by
7171     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7172     * characters of the same type are returned as complete tokens.
7173     * <pre>
7174     * StringUtils.splitByCharacterType(null)         = null
7175     * StringUtils.splitByCharacterType("")           = []
7176     * StringUtils.splitByCharacterType("ab de fg")   = ["ab", " ", "de", " ", "fg"]
7177     * StringUtils.splitByCharacterType("ab   de fg") = ["ab", "   ", "de", " ", "fg"]
7178     * StringUtils.splitByCharacterType("ab:cd:ef")   = ["ab", ":", "cd", ":", "ef"]
7179     * StringUtils.splitByCharacterType("number5")    = ["number", "5"]
7180     * StringUtils.splitByCharacterType("fooBar")     = ["foo", "B", "ar"]
7181     * StringUtils.splitByCharacterType("foo200Bar")  = ["foo", "200", "B", "ar"]
7182     * StringUtils.splitByCharacterType("ASFRules")   = ["ASFR", "ules"]
7183     * </pre>
7184     * @param str the String to split, may be {@code null}
7185     * @return an array of parsed Strings, {@code null} if null String input
7186     * @since 2.4
7187     */
7188    public static String[] splitByCharacterType(final String str) {
7189        return splitByCharacterType(str, false);
7190    }
7191
7192    /**
7193     * <p>Splits a String by Character type as returned by
7194     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7195     * characters of the same type are returned as complete tokens, with the
7196     * following exception: if {@code camelCase} is {@code true},
7197     * the character of type {@code Character.UPPERCASE_LETTER}, if any,
7198     * immediately preceding a token of type {@code Character.LOWERCASE_LETTER}
7199     * will belong to the following token rather than to the preceding, if any,
7200     * {@code Character.UPPERCASE_LETTER} token.
7201     * @param str the String to split, may be {@code null}
7202     * @param camelCase whether to use so-called "camel-case" for letter types
7203     * @return an array of parsed Strings, {@code null} if null String input
7204     * @since 2.4
7205     */
7206    private static String[] splitByCharacterType(final String str, final boolean camelCase) {
7207        if (str == null) {
7208            return null;
7209        }
7210        if (str.isEmpty()) {
7211            return ArrayUtils.EMPTY_STRING_ARRAY;
7212        }
7213        final char[] c = str.toCharArray();
7214        final List<String> list = new ArrayList<>();
7215        int tokenStart = 0;
7216        int currentType = Character.getType(c[tokenStart]);
7217        for (int pos = tokenStart + 1; pos < c.length; pos++) {
7218            final int type = Character.getType(c[pos]);
7219            if (type == currentType) {
7220                continue;
7221            }
7222            if (camelCase && type == Character.LOWERCASE_LETTER && currentType == Character.UPPERCASE_LETTER) {
7223                final int newTokenStart = pos - 1;
7224                if (newTokenStart != tokenStart) {
7225                    list.add(new String(c, tokenStart, newTokenStart - tokenStart));
7226                    tokenStart = newTokenStart;
7227                }
7228            } else {
7229                list.add(new String(c, tokenStart, pos - tokenStart));
7230                tokenStart = pos;
7231            }
7232            currentType = type;
7233        }
7234        list.add(new String(c, tokenStart, c.length - tokenStart));
7235        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7236    }
7237
7238    /**
7239     * <p>Splits a String by Character type as returned by
7240     * {@code java.lang.Character.getType(char)}. Groups of contiguous
7241     * characters of the same type are returned as complete tokens, with the
7242     * following exception: the character of type
7243     * {@code Character.UPPERCASE_LETTER}, if any, immediately
7244     * preceding a token of type {@code Character.LOWERCASE_LETTER}
7245     * will belong to the following token rather than to the preceding, if any,
7246     * {@code Character.UPPERCASE_LETTER} token.
7247     * <pre>
7248     * StringUtils.splitByCharacterTypeCamelCase(null)         = null
7249     * StringUtils.splitByCharacterTypeCamelCase("")           = []
7250     * StringUtils.splitByCharacterTypeCamelCase("ab de fg")   = ["ab", " ", "de", " ", "fg"]
7251     * StringUtils.splitByCharacterTypeCamelCase("ab   de fg") = ["ab", "   ", "de", " ", "fg"]
7252     * StringUtils.splitByCharacterTypeCamelCase("ab:cd:ef")   = ["ab", ":", "cd", ":", "ef"]
7253     * StringUtils.splitByCharacterTypeCamelCase("number5")    = ["number", "5"]
7254     * StringUtils.splitByCharacterTypeCamelCase("fooBar")     = ["foo", "Bar"]
7255     * StringUtils.splitByCharacterTypeCamelCase("foo200Bar")  = ["foo", "200", "Bar"]
7256     * StringUtils.splitByCharacterTypeCamelCase("ASFRules")   = ["ASF", "Rules"]
7257     * </pre>
7258     * @param str the String to split, may be {@code null}
7259     * @return an array of parsed Strings, {@code null} if null String input
7260     * @since 2.4
7261     */
7262    public static String[] splitByCharacterTypeCamelCase(final String str) {
7263        return splitByCharacterType(str, true);
7264    }
7265
7266    /**
7267     * <p>Splits the provided text into an array, separator string specified.
7268     *
7269     * <p>The separator(s) will not be included in the returned String array.
7270     * Adjacent separators are treated as one separator.</p>
7271     *
7272     * <p>A {@code null} input String returns {@code null}.
7273     * A {@code null} separator splits on whitespace.</p>
7274     *
7275     * <pre>
7276     * StringUtils.splitByWholeSeparator(null, *)               = null
7277     * StringUtils.splitByWholeSeparator("", *)                 = []
7278     * StringUtils.splitByWholeSeparator("ab de fg", null)      = ["ab", "de", "fg"]
7279     * StringUtils.splitByWholeSeparator("ab   de fg", null)    = ["ab", "de", "fg"]
7280     * StringUtils.splitByWholeSeparator("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
7281     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
7282     * </pre>
7283     *
7284     * @param str  the String to parse, may be null
7285     * @param separator  String containing the String to be used as a delimiter,
7286     *  {@code null} splits on whitespace
7287     * @return an array of parsed Strings, {@code null} if null String was input
7288     */
7289    public static String[] splitByWholeSeparator(final String str, final String separator) {
7290        return splitByWholeSeparatorWorker(str, separator, -1, false);
7291    }
7292
7293    /**
7294     * Splits the provided text into an array, separator string specified.
7295     * Returns a maximum of {@code max} substrings.
7296     *
7297     * <p>The separator(s) will not be included in the returned String array.
7298     * Adjacent separators are treated as one separator.</p>
7299     *
7300     * <p>A {@code null} input String returns {@code null}.
7301     * A {@code null} separator splits on whitespace.</p>
7302     *
7303     * <pre>
7304     * StringUtils.splitByWholeSeparator(null, *, *)               = null
7305     * StringUtils.splitByWholeSeparator("", *, *)                 = []
7306     * StringUtils.splitByWholeSeparator("ab de fg", null, 0)      = ["ab", "de", "fg"]
7307     * StringUtils.splitByWholeSeparator("ab   de fg", null, 0)    = ["ab", "de", "fg"]
7308     * StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
7309     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
7310     * StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
7311     * </pre>
7312     *
7313     * @param str  the String to parse, may be null
7314     * @param separator  String containing the String to be used as a delimiter,
7315     *  {@code null} splits on whitespace
7316     * @param max  the maximum number of elements to include in the returned
7317     *  array. A zero or negative value implies no limit.
7318     * @return an array of parsed Strings, {@code null} if null String was input
7319     */
7320    public static String[] splitByWholeSeparator(final String str, final String separator, final int max) {
7321        return splitByWholeSeparatorWorker(str, separator, max, false);
7322    }
7323
7324    /**
7325     * Splits the provided text into an array, separator string specified.
7326     *
7327     * <p>The separator is not included in the returned String array.
7328     * Adjacent separators are treated as separators for empty tokens.
7329     * For more control over the split use the StrTokenizer class.</p>
7330     *
7331     * <p>A {@code null} input String returns {@code null}.
7332     * A {@code null} separator splits on whitespace.</p>
7333     *
7334     * <pre>
7335     * StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *)               = null
7336     * StringUtils.splitByWholeSeparatorPreserveAllTokens("", *)                 = []
7337     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null)      = ["ab", "de", "fg"]
7338     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null)    = ["ab", "", "", "de", "fg"]
7339     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
7340     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
7341     * </pre>
7342     *
7343     * @param str  the String to parse, may be null
7344     * @param separator  String containing the String to be used as a delimiter,
7345     *  {@code null} splits on whitespace
7346     * @return an array of parsed Strings, {@code null} if null String was input
7347     * @since 2.4
7348     */
7349    public static String[] splitByWholeSeparatorPreserveAllTokens(final String str, final String separator) {
7350        return splitByWholeSeparatorWorker(str, separator, -1, true);
7351    }
7352
7353    /**
7354     * Splits the provided text into an array, separator string specified.
7355     * Returns a maximum of {@code max} substrings.
7356     *
7357     * <p>The separator is not included in the returned String array.
7358     * Adjacent separators are treated as separators for empty tokens.
7359     * For more control over the split use the StrTokenizer class.</p>
7360     *
7361     * <p>A {@code null} input String returns {@code null}.
7362     * A {@code null} separator splits on whitespace.</p>
7363     *
7364     * <pre>
7365     * StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *, *)               = null
7366     * StringUtils.splitByWholeSeparatorPreserveAllTokens("", *, *)                 = []
7367     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0)      = ["ab", "de", "fg"]
7368     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null, 0)    = ["ab", "", "", "de", "fg"]
7369     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
7370     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
7371     * StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
7372     * </pre>
7373     *
7374     * @param str  the String to parse, may be null
7375     * @param separator  String containing the String to be used as a delimiter,
7376     *  {@code null} splits on whitespace
7377     * @param max  the maximum number of elements to include in the returned
7378     *  array. A zero or negative value implies no limit.
7379     * @return an array of parsed Strings, {@code null} if null String was input
7380     * @since 2.4
7381     */
7382    public static String[] splitByWholeSeparatorPreserveAllTokens(final String str, final String separator, final int max) {
7383        return splitByWholeSeparatorWorker(str, separator, max, true);
7384    }
7385
7386    /**
7387     * Performs the logic for the {@code splitByWholeSeparatorPreserveAllTokens} methods.
7388     *
7389     * @param str  the String to parse, may be {@code null}
7390     * @param separator  String containing the String to be used as a delimiter,
7391     *  {@code null} splits on whitespace
7392     * @param max  the maximum number of elements to include in the returned
7393     *  array. A zero or negative value implies no limit.
7394     * @param preserveAllTokens if {@code true}, adjacent separators are
7395     * treated as empty token separators; if {@code false}, adjacent
7396     * separators are treated as one separator.
7397     * @return an array of parsed Strings, {@code null} if null String input
7398     * @since 2.4
7399     */
7400    private static String[] splitByWholeSeparatorWorker(
7401            final String str, final String separator, final int max, final boolean preserveAllTokens) {
7402        if (str == null) {
7403            return null;
7404        }
7405
7406        final int len = str.length();
7407
7408        if (len == 0) {
7409            return ArrayUtils.EMPTY_STRING_ARRAY;
7410        }
7411
7412        if (separator == null || EMPTY.equals(separator)) {
7413            // Split on whitespace.
7414            return splitWorker(str, null, max, preserveAllTokens);
7415        }
7416
7417        final int separatorLength = separator.length();
7418
7419        final ArrayList<String> substrings = new ArrayList<>();
7420        int numberOfSubstrings = 0;
7421        int beg = 0;
7422        int end = 0;
7423        while (end < len) {
7424            end = str.indexOf(separator, beg);
7425
7426            if (end > -1) {
7427                if (end > beg) {
7428                    numberOfSubstrings += 1;
7429
7430                    if (numberOfSubstrings == max) {
7431                        end = len;
7432                        substrings.add(str.substring(beg));
7433                    } else {
7434                        // The following is OK, because String.substring( beg, end ) excludes
7435                        // the character at the position 'end'.
7436                        substrings.add(str.substring(beg, end));
7437
7438                        // Set the starting point for the next search.
7439                        // The following is equivalent to beg = end + (separatorLength - 1) + 1,
7440                        // which is the right calculation:
7441                        beg = end + separatorLength;
7442                    }
7443                } else {
7444                    // We found a consecutive occurrence of the separator, so skip it.
7445                    if (preserveAllTokens) {
7446                        numberOfSubstrings += 1;
7447                        if (numberOfSubstrings == max) {
7448                            end = len;
7449                            substrings.add(str.substring(beg));
7450                        } else {
7451                            substrings.add(EMPTY);
7452                        }
7453                    }
7454                    beg = end + separatorLength;
7455                }
7456            } else {
7457                // String.substring( beg ) goes from 'beg' to the end of the String.
7458                substrings.add(str.substring(beg));
7459                end = len;
7460            }
7461        }
7462
7463        return substrings.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7464    }
7465
7466    /**
7467     * Splits the provided text into an array, using whitespace as the
7468     * separator, preserving all tokens, including empty tokens created by
7469     * adjacent separators. This is an alternative to using StringTokenizer.
7470     * Whitespace is defined by {@link Character#isWhitespace(char)}.
7471     *
7472     * <p>The separator is not included in the returned String array.
7473     * Adjacent separators are treated as separators for empty tokens.
7474     * For more control over the split use the StrTokenizer class.</p>
7475     *
7476     * <p>A {@code null} input String returns {@code null}.</p>
7477     *
7478     * <pre>
7479     * StringUtils.splitPreserveAllTokens(null)       = null
7480     * StringUtils.splitPreserveAllTokens("")         = []
7481     * StringUtils.splitPreserveAllTokens("abc def")  = ["abc", "def"]
7482     * StringUtils.splitPreserveAllTokens("abc  def") = ["abc", "", "def"]
7483     * StringUtils.splitPreserveAllTokens(" abc ")    = ["", "abc", ""]
7484     * </pre>
7485     *
7486     * @param str  the String to parse, may be {@code null}
7487     * @return an array of parsed Strings, {@code null} if null String input
7488     * @since 2.1
7489     */
7490    public static String[] splitPreserveAllTokens(final String str) {
7491        return splitWorker(str, null, -1, true);
7492    }
7493
7494    /**
7495     * Splits the provided text into an array, separator specified,
7496     * preserving all tokens, including empty tokens created by adjacent
7497     * separators. This is an alternative to using StringTokenizer.
7498     *
7499     * <p>The separator is not included in the returned String array.
7500     * Adjacent separators are treated as separators for empty tokens.
7501     * For more control over the split use the StrTokenizer class.</p>
7502     *
7503     * <p>A {@code null} input String returns {@code null}.</p>
7504     *
7505     * <pre>
7506     * StringUtils.splitPreserveAllTokens(null, *)         = null
7507     * StringUtils.splitPreserveAllTokens("", *)           = []
7508     * StringUtils.splitPreserveAllTokens("a.b.c", '.')    = ["a", "b", "c"]
7509     * StringUtils.splitPreserveAllTokens("a..b.c", '.')   = ["a", "", "b", "c"]
7510     * StringUtils.splitPreserveAllTokens("a:b:c", '.')    = ["a:b:c"]
7511     * StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
7512     * StringUtils.splitPreserveAllTokens("a b c", ' ')    = ["a", "b", "c"]
7513     * StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", ""]
7514     * StringUtils.splitPreserveAllTokens("a b c  ", ' ')  = ["a", "b", "c", "", ""]
7515     * StringUtils.splitPreserveAllTokens(" a b c", ' ')   = ["", "a", "b", "c"]
7516     * StringUtils.splitPreserveAllTokens("  a b c", ' ')  = ["", "", "a", "b", "c"]
7517     * StringUtils.splitPreserveAllTokens(" a b c ", ' ')  = ["", "a", "b", "c", ""]
7518     * </pre>
7519     *
7520     * @param str  the String to parse, may be {@code null}
7521     * @param separatorChar  the character used as the delimiter,
7522     *  {@code null} splits on whitespace
7523     * @return an array of parsed Strings, {@code null} if null String input
7524     * @since 2.1
7525     */
7526    public static String[] splitPreserveAllTokens(final String str, final char separatorChar) {
7527        return splitWorker(str, separatorChar, true);
7528    }
7529
7530    /**
7531     * Splits the provided text into an array, separators specified,
7532     * preserving all tokens, including empty tokens created by adjacent
7533     * separators. This is an alternative to using StringTokenizer.
7534     *
7535     * <p>The separator is not included in the returned String array.
7536     * Adjacent separators are treated as separators for empty tokens.
7537     * For more control over the split use the StrTokenizer class.</p>
7538     *
7539     * <p>A {@code null} input String returns {@code null}.
7540     * A {@code null} separatorChars splits on whitespace.</p>
7541     *
7542     * <pre>
7543     * StringUtils.splitPreserveAllTokens(null, *)           = null
7544     * StringUtils.splitPreserveAllTokens("", *)             = []
7545     * StringUtils.splitPreserveAllTokens("abc def", null)   = ["abc", "def"]
7546     * StringUtils.splitPreserveAllTokens("abc def", " ")    = ["abc", "def"]
7547     * StringUtils.splitPreserveAllTokens("abc  def", " ")   = ["abc", "", "def"]
7548     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":")   = ["ab", "cd", "ef"]
7549     * StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":")  = ["ab", "cd", "ef", ""]
7550     * StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
7551     * StringUtils.splitPreserveAllTokens("ab::cd:ef", ":")  = ["ab", "", "cd", "ef"]
7552     * StringUtils.splitPreserveAllTokens(":cd:ef", ":")     = ["", "cd", "ef"]
7553     * StringUtils.splitPreserveAllTokens("::cd:ef", ":")    = ["", "", "cd", "ef"]
7554     * StringUtils.splitPreserveAllTokens(":cd:ef:", ":")    = ["", "cd", "ef", ""]
7555     * </pre>
7556     *
7557     * @param str  the String to parse, may be {@code null}
7558     * @param separatorChars  the characters used as the delimiters,
7559     *  {@code null} splits on whitespace
7560     * @return an array of parsed Strings, {@code null} if null String input
7561     * @since 2.1
7562     */
7563    public static String[] splitPreserveAllTokens(final String str, final String separatorChars) {
7564        return splitWorker(str, separatorChars, -1, true);
7565    }
7566
7567    /**
7568     * Splits the provided text into an array with a maximum length,
7569     * separators specified, preserving all tokens, including empty tokens
7570     * created by adjacent separators.
7571     *
7572     * <p>The separator is not included in the returned String array.
7573     * Adjacent separators are treated as separators for empty tokens.
7574     * Adjacent separators are treated as one separator.</p>
7575     *
7576     * <p>A {@code null} input String returns {@code null}.
7577     * A {@code null} separatorChars splits on whitespace.</p>
7578     *
7579     * <p>If more than {@code max} delimited substrings are found, the last
7580     * returned string includes all characters after the first {@code max - 1}
7581     * returned strings (including separator characters).</p>
7582     *
7583     * <pre>
7584     * StringUtils.splitPreserveAllTokens(null, *, *)            = null
7585     * StringUtils.splitPreserveAllTokens("", *, *)              = []
7586     * StringUtils.splitPreserveAllTokens("ab de fg", null, 0)   = ["ab", "de", "fg"]
7587     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 0) = ["ab", "", "", "de", "fg"]
7588     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
7589     * StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
7590     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 2) = ["ab", "  de fg"]
7591     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 3) = ["ab", "", " de fg"]
7592     * StringUtils.splitPreserveAllTokens("ab   de fg", null, 4) = ["ab", "", "", "de fg"]
7593     * </pre>
7594     *
7595     * @param str  the String to parse, may be {@code null}
7596     * @param separatorChars  the characters used as the delimiters,
7597     *  {@code null} splits on whitespace
7598     * @param max  the maximum number of elements to include in the
7599     *  array. A zero or negative value implies no limit
7600     * @return an array of parsed Strings, {@code null} if null String input
7601     * @since 2.1
7602     */
7603    public static String[] splitPreserveAllTokens(final String str, final String separatorChars, final int max) {
7604        return splitWorker(str, separatorChars, max, true);
7605    }
7606
7607    /**
7608     * Performs the logic for the {@code split} and
7609     * {@code splitPreserveAllTokens} methods that do not return a
7610     * maximum array length.
7611     *
7612     * @param str  the String to parse, may be {@code null}
7613     * @param separatorChar the separate character
7614     * @param preserveAllTokens if {@code true}, adjacent separators are
7615     * treated as empty token separators; if {@code false}, adjacent
7616     * separators are treated as one separator.
7617     * @return an array of parsed Strings, {@code null} if null String input
7618     */
7619    private static String[] splitWorker(final String str, final char separatorChar, final boolean preserveAllTokens) {
7620        // Performance tuned for 2.0 (JDK1.4)
7621        if (str == null) {
7622            return null;
7623        }
7624        final int len = str.length();
7625        if (len == 0) {
7626            return ArrayUtils.EMPTY_STRING_ARRAY;
7627        }
7628        final List<String> list = new ArrayList<>();
7629        int i = 0;
7630        int start = 0;
7631        boolean match = false;
7632        boolean lastMatch = false;
7633        while (i < len) {
7634            if (str.charAt(i) == separatorChar) {
7635                if (match || preserveAllTokens) {
7636                    list.add(str.substring(start, i));
7637                    match = false;
7638                    lastMatch = true;
7639                }
7640                start = ++i;
7641                continue;
7642            }
7643            lastMatch = false;
7644            match = true;
7645            i++;
7646        }
7647        if (match || preserveAllTokens && lastMatch) {
7648            list.add(str.substring(start, i));
7649        }
7650        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7651    }
7652
7653    /**
7654     * Performs the logic for the {@code split} and
7655     * {@code splitPreserveAllTokens} methods that return a maximum array
7656     * length.
7657     *
7658     * @param str  the String to parse, may be {@code null}
7659     * @param separatorChars the separate character
7660     * @param max  the maximum number of elements to include in the
7661     *  array. A zero or negative value implies no limit.
7662     * @param preserveAllTokens if {@code true}, adjacent separators are
7663     * treated as empty token separators; if {@code false}, adjacent
7664     * separators are treated as one separator.
7665     * @return an array of parsed Strings, {@code null} if null String input
7666     */
7667    private static String[] splitWorker(final String str, final String separatorChars, final int max, final boolean preserveAllTokens) {
7668        // Performance tuned for 2.0 (JDK1.4)
7669        // Direct code is quicker than StringTokenizer.
7670        // Also, StringTokenizer uses isSpace() not isWhitespace()
7671
7672        if (str == null) {
7673            return null;
7674        }
7675        final int len = str.length();
7676        if (len == 0) {
7677            return ArrayUtils.EMPTY_STRING_ARRAY;
7678        }
7679        final List<String> list = new ArrayList<>();
7680        int sizePlus1 = 1;
7681        int i = 0;
7682        int start = 0;
7683        boolean match = false;
7684        boolean lastMatch = false;
7685        if (separatorChars == null) {
7686            // Null separator means use whitespace
7687            while (i < len) {
7688                if (Character.isWhitespace(str.charAt(i))) {
7689                    if (match || preserveAllTokens) {
7690                        lastMatch = true;
7691                        if (sizePlus1++ == max) {
7692                            i = len;
7693                            lastMatch = false;
7694                        }
7695                        list.add(str.substring(start, i));
7696                        match = false;
7697                    }
7698                    start = ++i;
7699                    continue;
7700                }
7701                lastMatch = false;
7702                match = true;
7703                i++;
7704            }
7705        } else if (separatorChars.length() == 1) {
7706            // Optimize 1 character case
7707            final char sep = separatorChars.charAt(0);
7708            while (i < len) {
7709                if (str.charAt(i) == sep) {
7710                    if (match || preserveAllTokens) {
7711                        lastMatch = true;
7712                        if (sizePlus1++ == max) {
7713                            i = len;
7714                            lastMatch = false;
7715                        }
7716                        list.add(str.substring(start, i));
7717                        match = false;
7718                    }
7719                    start = ++i;
7720                    continue;
7721                }
7722                lastMatch = false;
7723                match = true;
7724                i++;
7725            }
7726        } else {
7727            // standard case
7728            while (i < len) {
7729                if (separatorChars.indexOf(str.charAt(i)) >= 0) {
7730                    if (match || preserveAllTokens) {
7731                        lastMatch = true;
7732                        if (sizePlus1++ == max) {
7733                            i = len;
7734                            lastMatch = false;
7735                        }
7736                        list.add(str.substring(start, i));
7737                        match = false;
7738                    }
7739                    start = ++i;
7740                    continue;
7741                }
7742                lastMatch = false;
7743                match = true;
7744                i++;
7745            }
7746        }
7747        if (match || preserveAllTokens && lastMatch) {
7748            list.add(str.substring(start, i));
7749        }
7750        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
7751    }
7752
7753    /**
7754     * Tests if a CharSequence starts with a specified prefix.
7755     *
7756     * <p>{@code null}s are handled without exceptions. Two {@code null}
7757     * references are considered to be equal. The comparison is case-sensitive.</p>
7758     *
7759     * <pre>
7760     * StringUtils.startsWith(null, null)      = true
7761     * StringUtils.startsWith(null, "abc")     = false
7762     * StringUtils.startsWith("abcdef", null)  = false
7763     * StringUtils.startsWith("abcdef", "abc") = true
7764     * StringUtils.startsWith("ABCDEF", "abc") = false
7765     * </pre>
7766     *
7767     * @see String#startsWith(String)
7768     * @param str  the CharSequence to check, may be null
7769     * @param prefix the prefix to find, may be null
7770     * @return {@code true} if the CharSequence starts with the prefix, case-sensitive, or
7771     *  both {@code null}
7772     * @since 2.4
7773     * @since 3.0 Changed signature from startsWith(String, String) to startsWith(CharSequence, CharSequence)
7774     * @deprecated Use {@link Strings#startsWith(CharSequence, CharSequence) Strings.CS.startsWith(CharSequence, CharSequence)}
7775     */
7776    @Deprecated
7777    public static boolean startsWith(final CharSequence str, final CharSequence prefix) {
7778        return Strings.CS.startsWith(str, prefix);
7779    }
7780
7781    /**
7782     * Tests if a CharSequence starts with any of the provided case-sensitive prefixes.
7783     *
7784     * <pre>
7785     * StringUtils.startsWithAny(null, null)      = false
7786     * StringUtils.startsWithAny(null, new String[] {"abc"})  = false
7787     * StringUtils.startsWithAny("abcxyz", null)     = false
7788     * StringUtils.startsWithAny("abcxyz", new String[] {""}) = true
7789     * StringUtils.startsWithAny("abcxyz", new String[] {"abc"}) = true
7790     * StringUtils.startsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
7791     * StringUtils.startsWithAny("abcxyz", null, "xyz", "ABCX") = false
7792     * StringUtils.startsWithAny("ABCXYZ", null, "xyz", "abc") = false
7793     * </pre>
7794     *
7795     * @param sequence the CharSequence to check, may be null
7796     * @param searchStrings the case-sensitive CharSequence prefixes, may be empty or contain {@code null}
7797     * @see StringUtils#startsWith(CharSequence, CharSequence)
7798     * @return {@code true} if the input {@code sequence} is {@code null} AND no {@code searchStrings} are provided, or
7799     *   the input {@code sequence} begins with any of the provided case-sensitive {@code searchStrings}.
7800     * @since 2.5
7801     * @since 3.0 Changed signature from startsWithAny(String, String[]) to startsWithAny(CharSequence, CharSequence...)
7802     * @deprecated Use {@link Strings#startsWithAny(CharSequence, CharSequence...) Strings.CI.startsWithAny(CharSequence, CharSequence...)}
7803     */
7804    @Deprecated
7805    public static boolean startsWithAny(final CharSequence sequence, final CharSequence... searchStrings) {
7806        return Strings.CS.startsWithAny(sequence, searchStrings);
7807    }
7808
7809    /**
7810     * Case-insensitive check if a CharSequence starts with a specified prefix.
7811     *
7812     * <p>{@code null}s are handled without exceptions. Two {@code null}
7813     * references are considered to be equal. The comparison is case insensitive.</p>
7814     *
7815     * <pre>
7816     * StringUtils.startsWithIgnoreCase(null, null)      = true
7817     * StringUtils.startsWithIgnoreCase(null, "abc")     = false
7818     * StringUtils.startsWithIgnoreCase("abcdef", null)  = false
7819     * StringUtils.startsWithIgnoreCase("abcdef", "abc") = true
7820     * StringUtils.startsWithIgnoreCase("ABCDEF", "abc") = true
7821     * </pre>
7822     *
7823     * @see String#startsWith(String)
7824     * @param str  the CharSequence to check, may be null
7825     * @param prefix the prefix to find, may be null
7826     * @return {@code true} if the CharSequence starts with the prefix, case-insensitive, or
7827     *  both {@code null}
7828     * @since 2.4
7829     * @since 3.0 Changed signature from startsWithIgnoreCase(String, String) to startsWithIgnoreCase(CharSequence, CharSequence)
7830     * @deprecated Use {@link Strings#startsWith(CharSequence, CharSequence) Strings.CI.startsWith(CharSequence, CharSequence)}
7831     */
7832    @Deprecated
7833    public static boolean startsWithIgnoreCase(final CharSequence str, final CharSequence prefix) {
7834        return Strings.CI.startsWith(str, prefix);
7835    }
7836
7837    /**
7838     * Strips whitespace from the start and end of a String.
7839     *
7840     * <p>This is similar to {@link #trim(String)} but removes whitespace.
7841     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
7842     *
7843     * <p>A {@code null} input String returns {@code null}.</p>
7844     *
7845     * <pre>
7846     * StringUtils.strip(null)     = null
7847     * StringUtils.strip("")       = ""
7848     * StringUtils.strip("   ")    = ""
7849     * StringUtils.strip("abc")    = "abc"
7850     * StringUtils.strip("  abc")  = "abc"
7851     * StringUtils.strip("abc  ")  = "abc"
7852     * StringUtils.strip(" abc ")  = "abc"
7853     * StringUtils.strip(" ab c ") = "ab c"
7854     * </pre>
7855     *
7856     * @param str  the String to remove whitespace from, may be null
7857     * @return the stripped String, {@code null} if null String input
7858     */
7859    public static String strip(final String str) {
7860        return strip(str, null);
7861    }
7862
7863    /**
7864     * Strips any of a set of characters from the start and end of a String.
7865     * This is similar to {@link String#trim()} but allows the characters
7866     * to be stripped to be controlled.
7867     *
7868     * <p>A {@code null} input String returns {@code null}.
7869     * An empty string ("") input returns the empty string.</p>
7870     *
7871     * <p>If the stripChars String is {@code null}, whitespace is
7872     * stripped as defined by {@link Character#isWhitespace(char)}.
7873     * Alternatively use {@link #strip(String)}.</p>
7874     *
7875     * <pre>
7876     * StringUtils.strip(null, *)          = null
7877     * StringUtils.strip("", *)            = ""
7878     * StringUtils.strip("abc", null)      = "abc"
7879     * StringUtils.strip("  abc", null)    = "abc"
7880     * StringUtils.strip("abc  ", null)    = "abc"
7881     * StringUtils.strip(" abc ", null)    = "abc"
7882     * StringUtils.strip("  abcyx", "xyz") = "  abc"
7883     * </pre>
7884     *
7885     * @param str  the String to remove characters from, may be null
7886     * @param stripChars  the characters to remove, null treated as whitespace
7887     * @return the stripped String, {@code null} if null String input
7888     */
7889    public static String strip(String str, final String stripChars) {
7890        str = stripStart(str, stripChars);
7891        return stripEnd(str, stripChars);
7892    }
7893
7894    /**
7895     * Removes diacritics (~= accents) from a string. The case will not be altered.
7896     * <p>
7897     * For instance, '&agrave;' will be replaced by 'a'.
7898     * </p>
7899     * <p>
7900     * Decomposes ligatures and digraphs per the KD column in the <a href = "https://www.unicode.org/charts/normalization/">Unicode Normalization Chart.</a>
7901     * </p>
7902     * <pre>
7903     * StringUtils.stripAccents(null)         = null
7904     * StringUtils.stripAccents("")           = ""
7905     * StringUtils.stripAccents("control")    = "control"
7906     * StringUtils.stripAccents("&eacute;clair")     = "eclair"
7907     * StringUtils.stripAccents("\u1d43\u1d47\u1d9c\u00b9\u00b2\u00b3")     = "abc123"
7908     * StringUtils.stripAccents("\u00BC \u00BD \u00BE")      = "1⁄4 1⁄2 3⁄4"
7909     * </pre>
7910     * <p>
7911     * See also <a href="http://www.unicode.org/unicode/reports/tr15/tr15-23.html">Unicode Standard Annex #15 Unicode Normalization Forms</a>.
7912     * </p>
7913     *
7914     * @param input String to be stripped
7915     * @return input text with diacritics removed
7916     * @since 3.0
7917     */
7918    // 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).
7919    public static String stripAccents(final String input) {
7920        if (isEmpty(input)) {
7921            return input;
7922        }
7923        final StringBuilder decomposed = new StringBuilder(Normalizer.normalize(input, Normalizer.Form.NFKD));
7924        convertRemainingAccentCharacters(decomposed);
7925        return STRIP_ACCENTS_PATTERN.matcher(decomposed).replaceAll(EMPTY);
7926    }
7927
7928    /**
7929     * Strips whitespace from the start and end of every String in an array.
7930     * Whitespace is defined by {@link Character#isWhitespace(char)}.
7931     *
7932     * <p>A new array is returned each time, except for length zero.
7933     * A {@code null} array will return {@code null}.
7934     * An empty array will return itself.
7935     * A {@code null} array entry will be ignored.</p>
7936     *
7937     * <pre>
7938     * StringUtils.stripAll(null)             = null
7939     * StringUtils.stripAll([])               = []
7940     * StringUtils.stripAll(["abc", "  abc"]) = ["abc", "abc"]
7941     * StringUtils.stripAll(["abc  ", null])  = ["abc", null]
7942     * </pre>
7943     *
7944     * @param strs  the array to remove whitespace from, may be null
7945     * @return the stripped Strings, {@code null} if null array input
7946     */
7947    public static String[] stripAll(final String... strs) {
7948        return stripAll(strs, null);
7949    }
7950
7951    /**
7952     * Strips any of a set of characters from the start and end of every
7953     * String in an array.
7954     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
7955     *
7956     * <p>A new array is returned each time, except for length zero.
7957     * A {@code null} array will return {@code null}.
7958     * An empty array will return itself.
7959     * A {@code null} array entry will be ignored.
7960     * A {@code null} stripChars will strip whitespace as defined by
7961     * {@link Character#isWhitespace(char)}.</p>
7962     *
7963     * <pre>
7964     * StringUtils.stripAll(null, *)                = null
7965     * StringUtils.stripAll([], *)                  = []
7966     * StringUtils.stripAll(["abc", "  abc"], null) = ["abc", "abc"]
7967     * StringUtils.stripAll(["abc  ", null], null)  = ["abc", null]
7968     * StringUtils.stripAll(["abc  ", null], "yz")  = ["abc  ", null]
7969     * StringUtils.stripAll(["yabcz", null], "yz")  = ["abc", null]
7970     * </pre>
7971     *
7972     * @param strs  the array to remove characters from, may be null
7973     * @param stripChars  the characters to remove, null treated as whitespace
7974     * @return the stripped Strings, {@code null} if null array input
7975     */
7976    public static String[] stripAll(final String[] strs, final String stripChars) {
7977        final int strsLen = ArrayUtils.getLength(strs);
7978        if (strsLen == 0) {
7979            return strs;
7980        }
7981        final String[] newArr = new String[strsLen];
7982        Arrays.setAll(newArr, i -> strip(strs[i], stripChars));
7983        return newArr;
7984    }
7985
7986    /**
7987     * Strips any of a set of characters from the end of a String.
7988     *
7989     * <p>A {@code null} input String returns {@code null}.
7990     * An empty string ("") input returns the empty string.</p>
7991     *
7992     * <p>If the stripChars String is {@code null}, whitespace is
7993     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
7994     *
7995     * <pre>
7996     * StringUtils.stripEnd(null, *)          = null
7997     * StringUtils.stripEnd("", *)            = ""
7998     * StringUtils.stripEnd("abc", "")        = "abc"
7999     * StringUtils.stripEnd("abc", null)      = "abc"
8000     * StringUtils.stripEnd("  abc", null)    = "  abc"
8001     * StringUtils.stripEnd("abc  ", null)    = "abc"
8002     * StringUtils.stripEnd(" abc ", null)    = " abc"
8003     * StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
8004     * StringUtils.stripEnd("120.00", ".0")   = "12"
8005     * </pre>
8006     *
8007     * @param str  the String to remove characters from, may be null
8008     * @param stripChars  the set of characters to remove, null treated as whitespace
8009     * @return the stripped String, {@code null} if null String input
8010     */
8011    public static String stripEnd(final String str, final String stripChars) {
8012        int end = length(str);
8013        if (end == 0) {
8014            return str;
8015        }
8016
8017        if (stripChars == null) {
8018            while (end != 0 && Character.isWhitespace(str.charAt(end - 1))) {
8019                end--;
8020            }
8021        } else if (stripChars.isEmpty()) {
8022            return str;
8023        } else {
8024            while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
8025                end--;
8026            }
8027        }
8028        return str.substring(0, end);
8029    }
8030
8031    /**
8032     * Strips any of a set of characters from the start of a String.
8033     *
8034     * <p>A {@code null} input String returns {@code null}.
8035     * An empty string ("") input returns the empty string.</p>
8036     *
8037     * <p>If the stripChars String is {@code null}, whitespace is
8038     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
8039     *
8040     * <pre>
8041     * StringUtils.stripStart(null, *)          = null
8042     * StringUtils.stripStart("", *)            = ""
8043     * StringUtils.stripStart("abc", "")        = "abc"
8044     * StringUtils.stripStart("abc", null)      = "abc"
8045     * StringUtils.stripStart("  abc", null)    = "abc"
8046     * StringUtils.stripStart("abc  ", null)    = "abc  "
8047     * StringUtils.stripStart(" abc ", null)    = "abc "
8048     * StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
8049     * </pre>
8050     *
8051     * @param str  the String to remove characters from, may be null
8052     * @param stripChars  the characters to remove, null treated as whitespace
8053     * @return the stripped String, {@code null} if null String input
8054     */
8055    public static String stripStart(final String str, final String stripChars) {
8056        final int strLen = length(str);
8057        if (strLen == 0) {
8058            return str;
8059        }
8060        int start = 0;
8061        if (stripChars == null) {
8062            while (start != strLen && Character.isWhitespace(str.charAt(start))) {
8063                start++;
8064            }
8065        } else if (stripChars.isEmpty()) {
8066            return str;
8067        } else {
8068            while (start != strLen && stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND) {
8069                start++;
8070            }
8071        }
8072        return str.substring(start);
8073    }
8074
8075    /**
8076     * Strips whitespace from the start and end of a String  returning
8077     * an empty String if {@code null} input.
8078     *
8079     * <p>This is similar to {@link #trimToEmpty(String)} but removes whitespace.
8080     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8081     *
8082     * <pre>
8083     * StringUtils.stripToEmpty(null)     = ""
8084     * StringUtils.stripToEmpty("")       = ""
8085     * StringUtils.stripToEmpty("   ")    = ""
8086     * StringUtils.stripToEmpty("abc")    = "abc"
8087     * StringUtils.stripToEmpty("  abc")  = "abc"
8088     * StringUtils.stripToEmpty("abc  ")  = "abc"
8089     * StringUtils.stripToEmpty(" abc ")  = "abc"
8090     * StringUtils.stripToEmpty(" ab c ") = "ab c"
8091     * </pre>
8092     *
8093     * @param str  the String to be stripped, may be null
8094     * @return the trimmed String, or an empty String if {@code null} input
8095     * @since 2.0
8096     */
8097    public static String stripToEmpty(final String str) {
8098        return str == null ? EMPTY : strip(str, null);
8099    }
8100
8101    /**
8102     * Strips whitespace from the start and end of a String  returning
8103     * {@code null} if the String is empty ("") after the strip.
8104     *
8105     * <p>This is similar to {@link #trimToNull(String)} but removes whitespace.
8106     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
8107     *
8108     * <pre>
8109     * StringUtils.stripToNull(null)     = null
8110     * StringUtils.stripToNull("")       = null
8111     * StringUtils.stripToNull("   ")    = null
8112     * StringUtils.stripToNull("abc")    = "abc"
8113     * StringUtils.stripToNull("  abc")  = "abc"
8114     * StringUtils.stripToNull("abc  ")  = "abc"
8115     * StringUtils.stripToNull(" abc ")  = "abc"
8116     * StringUtils.stripToNull(" ab c ") = "ab c"
8117     * </pre>
8118     *
8119     * @param str  the String to be stripped, may be null
8120     * @return the stripped String,
8121     *  {@code null} if whitespace, empty or null String input
8122     * @since 2.0
8123     */
8124    public static String stripToNull(String str) {
8125        if (str == null) {
8126            return null;
8127        }
8128        str = strip(str, null);
8129        return str.isEmpty() ? null : str; // NOSONARLINT str cannot be null here
8130    }
8131
8132    /**
8133     * Gets a substring from the specified String avoiding exceptions.
8134     *
8135     * <p>A negative start position can be used to start {@code n}
8136     * characters from the end of the String.</p>
8137     *
8138     * <p>A {@code null} String will return {@code null}.
8139     * An empty ("") String will return "".</p>
8140     *
8141     * <pre>
8142     * StringUtils.substring(null, *)   = null
8143     * StringUtils.substring("", *)     = ""
8144     * StringUtils.substring("abc", 0)  = "abc"
8145     * StringUtils.substring("abc", 2)  = "c"
8146     * StringUtils.substring("abc", 4)  = ""
8147     * StringUtils.substring("abc", -2) = "bc"
8148     * StringUtils.substring("abc", -4) = "abc"
8149     * </pre>
8150     *
8151     * @param str  the String to get the substring from, may be null
8152     * @param start  the position to start from, negative means
8153     *  count back from the end of the String by this many characters
8154     * @return substring from start position, {@code null} if null String input
8155     */
8156    public static String substring(final String str, int start) {
8157        if (str == null) {
8158            return null;
8159        }
8160
8161        // handle negatives, which means last n characters
8162        if (start < 0) {
8163            start = str.length() + start; // remember start is negative
8164        }
8165
8166        if (start < 0) {
8167            start = 0;
8168        }
8169        if (start > str.length()) {
8170            return EMPTY;
8171        }
8172
8173        return str.substring(start);
8174    }
8175
8176    /**
8177     * Gets a substring from the specified String avoiding exceptions.
8178     *
8179     * <p>A negative start position can be used to start/end {@code n}
8180     * characters from the end of the String.</p>
8181     *
8182     * <p>The returned substring starts with the character in the {@code start}
8183     * position and ends before the {@code end} position. All position counting is
8184     * zero-based -- i.e., to start at the beginning of the string use
8185     * {@code start = 0}. Negative start and end positions can be used to
8186     * specify offsets relative to the end of the String.</p>
8187     *
8188     * <p>If {@code start} is not strictly to the left of {@code end}, ""
8189     * is returned.</p>
8190     *
8191     * <pre>
8192     * StringUtils.substring(null, *, *)    = null
8193     * StringUtils.substring("", * ,  *)    = "";
8194     * StringUtils.substring("abc", 0, 2)   = "ab"
8195     * StringUtils.substring("abc", 2, 0)   = ""
8196     * StringUtils.substring("abc", 2, 4)   = "c"
8197     * StringUtils.substring("abc", 4, 6)   = ""
8198     * StringUtils.substring("abc", 2, 2)   = ""
8199     * StringUtils.substring("abc", -2, -1) = "b"
8200     * StringUtils.substring("abc", -4, 2)  = "ab"
8201     * </pre>
8202     *
8203     * @param str  the String to get the substring from, may be null
8204     * @param start  the position to start from, negative means
8205     *  count back from the end of the String by this many characters
8206     * @param end  the position to end at (exclusive), negative means
8207     *  count back from the end of the String by this many characters
8208     * @return substring from start position to end position,
8209     *  {@code null} if null String input
8210     */
8211    public static String substring(final String str, int start, int end) {
8212        if (str == null) {
8213            return null;
8214        }
8215
8216        // handle negatives
8217        if (end < 0) {
8218            end = str.length() + end; // remember end is negative
8219        }
8220        if (start < 0) {
8221            start = str.length() + start; // remember start is negative
8222        }
8223
8224        // check length next
8225        if (end > str.length()) {
8226            end = str.length();
8227        }
8228
8229        // if start is greater than end, return ""
8230        if (start > end) {
8231            return EMPTY;
8232        }
8233
8234        if (start < 0) {
8235            start = 0;
8236        }
8237        if (end < 0) {
8238            end = 0;
8239        }
8240
8241        return str.substring(start, end);
8242    }
8243
8244    /**
8245     * Gets the substring after the first occurrence of a separator.
8246     * The separator is not returned.
8247     *
8248     * <p>A {@code null} string input will return {@code null}.
8249     * An empty ("") string input will return the empty string.
8250     *
8251     * <p>If nothing is found, the empty string is returned.</p>
8252     *
8253     * <pre>
8254     * StringUtils.substringAfter(null, *)      = null
8255     * StringUtils.substringAfter("", *)        = ""
8256     * StringUtils.substringAfter("abc", 'a')   = "bc"
8257     * StringUtils.substringAfter("abcba", 'b') = "cba"
8258     * StringUtils.substringAfter("abc", 'c')   = ""
8259     * StringUtils.substringAfter("abc", 'd')   = ""
8260     * StringUtils.substringAfter(" abc", 32)   = "abc"
8261     * </pre>
8262     *
8263     * @param str  the String to get a substring from, may be null
8264     * @param separator  the character (Unicode code point) to search.
8265     * @return the substring after the first occurrence of the separator,
8266     *  {@code null} if null String input
8267     * @since 3.11
8268     */
8269    public static String substringAfter(final String str, final int separator) {
8270        if (isEmpty(str)) {
8271            return str;
8272        }
8273        final int pos = str.indexOf(separator);
8274        if (pos == INDEX_NOT_FOUND) {
8275            return EMPTY;
8276        }
8277        return str.substring(pos + 1);
8278    }
8279
8280    /**
8281     * Gets the substring after the first occurrence of a separator.
8282     * The separator is not returned.
8283     *
8284     * <p>A {@code null} string input will return {@code null}.
8285     * An empty ("") string input will return the empty string.
8286     * A {@code null} separator will return the empty string if the
8287     * input string is not {@code null}.</p>
8288     *
8289     * <p>If nothing is found, the empty string is returned.</p>
8290     *
8291     * <pre>
8292     * StringUtils.substringAfter(null, *)      = null
8293     * StringUtils.substringAfter("", *)        = ""
8294     * StringUtils.substringAfter(*, null)      = ""
8295     * StringUtils.substringAfter("abc", "a")   = "bc"
8296     * StringUtils.substringAfter("abcba", "b") = "cba"
8297     * StringUtils.substringAfter("abc", "c")   = ""
8298     * StringUtils.substringAfter("abc", "d")   = ""
8299     * StringUtils.substringAfter("abc", "")    = "abc"
8300     * </pre>
8301     *
8302     * @param str  the String to get a substring from, may be null
8303     * @param separator  the String to search for, may be null
8304     * @return the substring after the first occurrence of the separator,
8305     *  {@code null} if null String input
8306     * @since 2.0
8307     */
8308    public static String substringAfter(final String str, final String separator) {
8309        if (isEmpty(str)) {
8310            return str;
8311        }
8312        if (separator == null) {
8313            return EMPTY;
8314        }
8315        final int pos = str.indexOf(separator);
8316        if (pos == INDEX_NOT_FOUND) {
8317            return EMPTY;
8318        }
8319        return str.substring(pos + separator.length());
8320    }
8321
8322    /**
8323     * Gets the substring after the last occurrence of a separator.
8324     * The separator is not returned.
8325     *
8326     * <p>A {@code null} string input will return {@code null}.
8327     * An empty ("") string input will return the empty string.
8328     *
8329     * <p>If nothing is found, the empty string is returned.</p>
8330     *
8331     * <pre>
8332     * StringUtils.substringAfterLast(null, *)      = null
8333     * StringUtils.substringAfterLast("", *)        = ""
8334     * StringUtils.substringAfterLast("abc", 'a')   = "bc"
8335     * StringUtils.substringAfterLast(" bc", 32)    = "bc"
8336     * StringUtils.substringAfterLast("abcba", 'b') = "a"
8337     * StringUtils.substringAfterLast("abc", 'c')   = ""
8338     * StringUtils.substringAfterLast("a", 'a')     = ""
8339     * StringUtils.substringAfterLast("a", 'z')     = ""
8340     * </pre>
8341     *
8342     * @param str  the String to get a substring from, may be null
8343     * @param separator  the character (Unicode code point) to search.
8344     * @return the substring after the last occurrence of the separator,
8345     *  {@code null} if null String input
8346     * @since 3.11
8347     */
8348    public static String substringAfterLast(final String str, final int separator) {
8349        if (isEmpty(str)) {
8350            return str;
8351        }
8352        final int pos = str.lastIndexOf(separator);
8353        if (pos == INDEX_NOT_FOUND || pos == str.length() - 1) {
8354            return EMPTY;
8355        }
8356        return str.substring(pos + 1);
8357    }
8358
8359    /**
8360     * Gets the substring after the last occurrence of a separator.
8361     * The separator is not returned.
8362     *
8363     * <p>A {@code null} string input will return {@code null}.
8364     * An empty ("") string input will return the empty string.
8365     * An empty or {@code null} separator will return the empty string if
8366     * the input string is not {@code null}.</p>
8367     *
8368     * <p>If nothing is found, the empty string is returned.</p>
8369     *
8370     * <pre>
8371     * StringUtils.substringAfterLast(null, *)      = null
8372     * StringUtils.substringAfterLast("", *)        = ""
8373     * StringUtils.substringAfterLast(*, "")        = ""
8374     * StringUtils.substringAfterLast(*, null)      = ""
8375     * StringUtils.substringAfterLast("abc", "a")   = "bc"
8376     * StringUtils.substringAfterLast("abcba", "b") = "a"
8377     * StringUtils.substringAfterLast("abc", "c")   = ""
8378     * StringUtils.substringAfterLast("a", "a")     = ""
8379     * StringUtils.substringAfterLast("a", "z")     = ""
8380     * </pre>
8381     *
8382     * @param str  the String to get a substring from, may be null
8383     * @param separator  the String to search for, may be null
8384     * @return the substring after the last occurrence of the separator,
8385     *  {@code null} if null String input
8386     * @since 2.0
8387     */
8388    public static String substringAfterLast(final String str, final String separator) {
8389        if (isEmpty(str)) {
8390            return str;
8391        }
8392        if (isEmpty(separator)) {
8393            return EMPTY;
8394        }
8395        final int pos = str.lastIndexOf(separator);
8396        if (pos == INDEX_NOT_FOUND || pos == str.length() - separator.length()) {
8397            return EMPTY;
8398        }
8399        return str.substring(pos + separator.length());
8400    }
8401
8402    /**
8403     * Gets the substring before the first occurrence of a separator. The separator is not returned.
8404     *
8405     * <p>
8406     * A {@code null} string input will return {@code null}. An empty ("") string input will return the empty string.
8407     * </p>
8408     *
8409     * <p>
8410     * If nothing is found, the string input is returned.
8411     * </p>
8412     *
8413     * <pre>
8414     * StringUtils.substringBefore(null, *)      = null
8415     * StringUtils.substringBefore("", *)        = ""
8416     * StringUtils.substringBefore("abc", 'a')   = ""
8417     * StringUtils.substringBefore("abcba", 'b') = "a"
8418     * StringUtils.substringBefore("abc", 'c')   = "ab"
8419     * StringUtils.substringBefore("abc", 'd')   = "abc"
8420     * </pre>
8421     *
8422     * @param str the String to get a substring from, may be null
8423     * @param separator the character (Unicode code point) to search.
8424     * @return the substring before the first occurrence of the separator, {@code null} if null String input
8425     * @since 3.12.0
8426     */
8427    public static String substringBefore(final String str, final int separator) {
8428        if (isEmpty(str)) {
8429            return str;
8430        }
8431        final int pos = str.indexOf(separator);
8432        if (pos == INDEX_NOT_FOUND) {
8433            return str;
8434        }
8435        return str.substring(0, pos);
8436    }
8437
8438    /**
8439     * Gets the substring before the first occurrence of a separator.
8440     * The separator is not returned.
8441     *
8442     * <p>A {@code null} string input will return {@code null}.
8443     * An empty ("") string input will return the empty string.
8444     * A {@code null} separator will return the input string.</p>
8445     *
8446     * <p>If nothing is found, the string input is returned.</p>
8447     *
8448     * <pre>
8449     * StringUtils.substringBefore(null, *)      = null
8450     * StringUtils.substringBefore("", *)        = ""
8451     * StringUtils.substringBefore("abc", "a")   = ""
8452     * StringUtils.substringBefore("abcba", "b") = "a"
8453     * StringUtils.substringBefore("abc", "c")   = "ab"
8454     * StringUtils.substringBefore("abc", "d")   = "abc"
8455     * StringUtils.substringBefore("abc", "")    = ""
8456     * StringUtils.substringBefore("abc", null)  = "abc"
8457     * </pre>
8458     *
8459     * @param str  the String to get a substring from, may be null
8460     * @param separator  the String to search for, may be null
8461     * @return the substring before the first occurrence of the separator,
8462     *  {@code null} if null String input
8463     * @since 2.0
8464     */
8465    public static String substringBefore(final String str, final String separator) {
8466        if (isEmpty(str) || separator == null) {
8467            return str;
8468        }
8469        if (separator.isEmpty()) {
8470            return EMPTY;
8471        }
8472        final int pos = str.indexOf(separator);
8473        if (pos == INDEX_NOT_FOUND) {
8474            return str;
8475        }
8476        return str.substring(0, pos);
8477    }
8478
8479    /**
8480     * Gets the substring before the last occurrence of a separator.
8481     * The separator is not returned.
8482     *
8483     * <p>A {@code null} string input will return {@code null}.
8484     * An empty ("") string input will return the empty string.
8485     * An empty or {@code null} separator will return the input string.</p>
8486     *
8487     * <p>If nothing is found, the string input is returned.</p>
8488     *
8489     * <pre>
8490     * StringUtils.substringBeforeLast(null, *)      = null
8491     * StringUtils.substringBeforeLast("", *)        = ""
8492     * StringUtils.substringBeforeLast("abcba", "b") = "abc"
8493     * StringUtils.substringBeforeLast("abc", "c")   = "ab"
8494     * StringUtils.substringBeforeLast("a", "a")     = ""
8495     * StringUtils.substringBeforeLast("a", "z")     = "a"
8496     * StringUtils.substringBeforeLast("a", null)    = "a"
8497     * StringUtils.substringBeforeLast("a", "")      = "a"
8498     * </pre>
8499     *
8500     * @param str  the String to get a substring from, may be null
8501     * @param separator  the String to search for, may be null
8502     * @return the substring before the last occurrence of the separator,
8503     *  {@code null} if null String input
8504     * @since 2.0
8505     */
8506    public static String substringBeforeLast(final String str, final String separator) {
8507        if (isEmpty(str) || isEmpty(separator)) {
8508            return str;
8509        }
8510        final int pos = str.lastIndexOf(separator);
8511        if (pos == INDEX_NOT_FOUND) {
8512            return str;
8513        }
8514        return str.substring(0, pos);
8515    }
8516
8517    /**
8518     * Gets the String that is nested in between two instances of the
8519     * same String.
8520     *
8521     * <p>A {@code null} input String returns {@code null}.
8522     * A {@code null} tag returns {@code null}.</p>
8523     *
8524     * <pre>
8525     * StringUtils.substringBetween(null, *)            = null
8526     * StringUtils.substringBetween("", "")             = ""
8527     * StringUtils.substringBetween("", "tag")          = null
8528     * StringUtils.substringBetween("tagabctag", null)  = null
8529     * StringUtils.substringBetween("tagabctag", "")    = ""
8530     * StringUtils.substringBetween("tagabctag", "tag") = "abc"
8531     * </pre>
8532     *
8533     * @param str  the String containing the substring, may be null
8534     * @param tag  the String before and after the substring, may be null
8535     * @return the substring, {@code null} if no match
8536     * @since 2.0
8537     */
8538    public static String substringBetween(final String str, final String tag) {
8539        return substringBetween(str, tag, tag);
8540    }
8541
8542    /**
8543     * Gets the String that is nested in between two Strings.
8544     * Only the first match is returned.
8545     *
8546     * <p>A {@code null} input String returns {@code null}.
8547     * A {@code null} open/close returns {@code null} (no match).
8548     * An empty ("") open and close returns an empty string.</p>
8549     *
8550     * <pre>
8551     * StringUtils.substringBetween("wx[b]yz", "[", "]") = "b"
8552     * StringUtils.substringBetween(null, *, *)          = null
8553     * StringUtils.substringBetween(*, null, *)          = null
8554     * StringUtils.substringBetween(*, *, null)          = null
8555     * StringUtils.substringBetween("", "", "")          = ""
8556     * StringUtils.substringBetween("", "", "]")         = null
8557     * StringUtils.substringBetween("", "[", "]")        = null
8558     * StringUtils.substringBetween("yabcz", "", "")     = ""
8559     * StringUtils.substringBetween("yabcz", "y", "z")   = "abc"
8560     * StringUtils.substringBetween("yabczyabcz", "y", "z")   = "abc"
8561     * </pre>
8562     *
8563     * @param str  the String containing the substring, may be null
8564     * @param open  the String before the substring, may be null
8565     * @param close  the String after the substring, may be null
8566     * @return the substring, {@code null} if no match
8567     * @since 2.0
8568     */
8569    public static String substringBetween(final String str, final String open, final String close) {
8570        if (!ObjectUtils.allNotNull(str, open, close)) {
8571            return null;
8572        }
8573        final int start = str.indexOf(open);
8574        if (start != INDEX_NOT_FOUND) {
8575            final int end = str.indexOf(close, start + open.length());
8576            if (end != INDEX_NOT_FOUND) {
8577                return str.substring(start + open.length(), end);
8578            }
8579        }
8580        return null;
8581    }
8582
8583    /**
8584     * Searches a String for substrings delimited by a start and end tag,
8585     * returning all matching substrings in an array.
8586     *
8587     * <p>A {@code null} input String returns {@code null}.
8588     * A {@code null} open/close returns {@code null} (no match).
8589     * An empty ("") open/close returns {@code null} (no match).</p>
8590     *
8591     * <pre>
8592     * StringUtils.substringsBetween("[a][b][c]", "[", "]") = ["a","b","c"]
8593     * StringUtils.substringsBetween(null, *, *)            = null
8594     * StringUtils.substringsBetween(*, null, *)            = null
8595     * StringUtils.substringsBetween(*, *, null)            = null
8596     * StringUtils.substringsBetween("", "[", "]")          = []
8597     * </pre>
8598     *
8599     * @param str  the String containing the substrings, null returns null, empty returns empty
8600     * @param open  the String identifying the start of the substring, empty returns null
8601     * @param close  the String identifying the end of the substring, empty returns null
8602     * @return a String Array of substrings, or {@code null} if no match
8603     * @since 2.3
8604     */
8605    public static String[] substringsBetween(final String str, final String open, final String close) {
8606        if (str == null || isEmpty(open) || isEmpty(close)) {
8607            return null;
8608        }
8609        final int strLen = str.length();
8610        if (strLen == 0) {
8611            return ArrayUtils.EMPTY_STRING_ARRAY;
8612        }
8613        final int closeLen = close.length();
8614        final int openLen = open.length();
8615        final List<String> list = new ArrayList<>();
8616        int pos = 0;
8617        while (pos < strLen - closeLen) {
8618            int start = str.indexOf(open, pos);
8619            if (start < 0) {
8620                break;
8621            }
8622            start += openLen;
8623            final int end = str.indexOf(close, start);
8624            if (end < 0) {
8625                break;
8626            }
8627            list.add(str.substring(start, end));
8628            pos = end + closeLen;
8629        }
8630        if (list.isEmpty()) {
8631            return null;
8632        }
8633        return list.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
8634    }
8635
8636    /**
8637     * Swaps the case of a String changing upper and title case to
8638     * lower case, and lower case to upper case.
8639     *
8640     * <ul>
8641     *  <li>Upper case character converts to Lower case</li>
8642     *  <li>Title case character converts to Lower case</li>
8643     *  <li>Lower case character converts to Upper case</li>
8644     * </ul>
8645     *
8646     * <p>For a word based algorithm, see {@link org.apache.commons.text.WordUtils#swapCase(String)}.
8647     * A {@code null} input String returns {@code null}.</p>
8648     *
8649     * <pre>
8650     * StringUtils.swapCase(null)                 = null
8651     * StringUtils.swapCase("")                   = ""
8652     * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
8653     * </pre>
8654     *
8655     * <p>NOTE: This method changed in Lang version 2.0.
8656     * It no longer performs a word based algorithm.
8657     * If you only use ASCII, you will notice no change.
8658     * That functionality is available in org.apache.commons.lang3.text.WordUtils.</p>
8659     *
8660     * @param str  the String to swap case, may be null
8661     * @return the changed String, {@code null} if null String input
8662     */
8663    public static String swapCase(final String str) {
8664        if (isEmpty(str)) {
8665            return str;
8666        }
8667
8668        final int strLen = str.length();
8669        final int[] newCodePoints = new int[strLen]; // cannot be longer than the char array
8670        int outOffset = 0;
8671        for (int i = 0; i < strLen; ) {
8672            final int oldCodepoint = str.codePointAt(i);
8673            final int newCodePoint;
8674            if (Character.isUpperCase(oldCodepoint) || Character.isTitleCase(oldCodepoint)) {
8675                newCodePoint = Character.toLowerCase(oldCodepoint);
8676            } else if (Character.isLowerCase(oldCodepoint)) {
8677                newCodePoint = Character.toUpperCase(oldCodepoint);
8678            } else {
8679                newCodePoint = oldCodepoint;
8680            }
8681            newCodePoints[outOffset++] = newCodePoint;
8682            i += Character.charCount(newCodePoint);
8683         }
8684        return new String(newCodePoints, 0, outOffset);
8685    }
8686
8687    /**
8688     * Converts a {@link CharSequence} into an array of code points.
8689     *
8690     * <p>Valid pairs of surrogate code units will be converted into a single supplementary
8691     * code point. Isolated surrogate code units (i.e. a high surrogate not followed by a low surrogate or
8692     * a low surrogate not preceded by a high surrogate) will be returned as-is.</p>
8693     *
8694     * <pre>
8695     * StringUtils.toCodePoints(null)   =  null
8696     * StringUtils.toCodePoints("")     =  []  // empty array
8697     * </pre>
8698     *
8699     * @param cs the character sequence to convert
8700     * @return an array of code points
8701     * @since 3.6
8702     */
8703    public static int[] toCodePoints(final CharSequence cs) {
8704        if (cs == null) {
8705            return null;
8706        }
8707        if (cs.length() == 0) {
8708            return ArrayUtils.EMPTY_INT_ARRAY;
8709        }
8710        return cs.toString().codePoints().toArray();
8711    }
8712
8713    /**
8714     * Converts a {@code byte[]} to a String using the specified character encoding.
8715     *
8716     * @param bytes
8717     *            the byte array to read from
8718     * @param charset
8719     *            the encoding to use, if null then use the platform default
8720     * @return a new String
8721     * @throws NullPointerException
8722     *             if {@code bytes} is null
8723     * @since 3.2
8724     * @since 3.3 No longer throws {@link UnsupportedEncodingException}.
8725     */
8726    public static String toEncodedString(final byte[] bytes, final Charset charset) {
8727        return new String(bytes, Charsets.toCharset(charset));
8728    }
8729
8730    /**
8731     * Converts the given source String as a lower-case using the {@link Locale#ROOT} locale in a null-safe manner.
8732     *
8733     * @param source A source String or null.
8734     * @return the given source String as a lower-case using the {@link Locale#ROOT} locale or null.
8735     * @since 3.10
8736     */
8737    public static String toRootLowerCase(final String source) {
8738        return source == null ? null : source.toLowerCase(Locale.ROOT);
8739    }
8740
8741    /**
8742     * Converts the given source String as an upper-case using the {@link Locale#ROOT} locale in a null-safe manner.
8743     *
8744     * @param source A source String or null.
8745     * @return the given source String as an upper-case using the {@link Locale#ROOT} locale or null.
8746     * @since 3.10
8747     */
8748    public static String toRootUpperCase(final String source) {
8749        return source == null ? null : source.toUpperCase(Locale.ROOT);
8750    }
8751
8752    /**
8753     * Converts a {@code byte[]} to a String using the specified character encoding.
8754     *
8755     * @param bytes
8756     *            the byte array to read from
8757     * @param charsetName
8758     *            the encoding to use, if null then use the platform default
8759     * @return a new String
8760     * @throws NullPointerException
8761     *             if the input is null
8762     * @deprecated use {@link StringUtils#toEncodedString(byte[], Charset)} instead of String constants in your code
8763     * @since 3.1
8764     */
8765    @Deprecated
8766    public static String toString(final byte[] bytes, final String charsetName) {
8767        return new String(bytes, Charsets.toCharset(charsetName));
8768    }
8769
8770    /**
8771     * Removes control characters (char &lt;= 32) from both
8772     * ends of this String, handling {@code null} by returning
8773     * {@code null}.
8774     *
8775     * <p>The String is trimmed using {@link String#trim()}.
8776     * Trim removes start and end characters &lt;= 32.
8777     * To strip whitespace use {@link #strip(String)}.</p>
8778     *
8779     * <p>To trim your choice of characters, use the
8780     * {@link #strip(String, String)} methods.</p>
8781     *
8782     * <pre>
8783     * StringUtils.trim(null)          = null
8784     * StringUtils.trim("")            = ""
8785     * StringUtils.trim("     ")       = ""
8786     * StringUtils.trim("abc")         = "abc"
8787     * StringUtils.trim("    abc    ") = "abc"
8788     * </pre>
8789     *
8790     * @param str  the String to be trimmed, may be null
8791     * @return the trimmed string, {@code null} if null String input
8792     */
8793    public static String trim(final String str) {
8794        return str == null ? null : str.trim();
8795    }
8796
8797    /**
8798     * Removes control characters (char &lt;= 32) from both
8799     * ends of this String returning an empty String ("") if the String
8800     * is empty ("") after the trim or if it is {@code null}.
8801     *
8802     * <p>The String is trimmed using {@link String#trim()}.
8803     * Trim removes start and end characters &lt;= 32.
8804     * To strip whitespace use {@link #stripToEmpty(String)}.
8805     *
8806     * <pre>
8807     * StringUtils.trimToEmpty(null)          = ""
8808     * StringUtils.trimToEmpty("")            = ""
8809     * StringUtils.trimToEmpty("     ")       = ""
8810     * StringUtils.trimToEmpty("abc")         = "abc"
8811     * StringUtils.trimToEmpty("    abc    ") = "abc"
8812     * </pre>
8813     *
8814     * @param str  the String to be trimmed, may be null
8815     * @return the trimmed String, or an empty String if {@code null} input
8816     * @since 2.0
8817     */
8818    public static String trimToEmpty(final String str) {
8819        return str == null ? EMPTY : str.trim();
8820    }
8821
8822    /**
8823     * Removes control characters (char &lt;= 32) from both
8824     * ends of this String returning {@code null} if the String is
8825     * empty ("") after the trim or if it is {@code null}.
8826     *
8827     * <p>The String is trimmed using {@link String#trim()}.
8828     * Trim removes start and end characters &lt;= 32.
8829     * To strip whitespace use {@link #stripToNull(String)}.
8830     *
8831     * <pre>
8832     * StringUtils.trimToNull(null)          = null
8833     * StringUtils.trimToNull("")            = null
8834     * StringUtils.trimToNull("     ")       = null
8835     * StringUtils.trimToNull("abc")         = "abc"
8836     * StringUtils.trimToNull("    abc    ") = "abc"
8837     * </pre>
8838     *
8839     * @param str  the String to be trimmed, may be null
8840     * @return the trimmed String,
8841     *  {@code null} if only chars &lt;= 32, empty or null String input
8842     * @since 2.0
8843     */
8844    public static String trimToNull(final String str) {
8845        final String ts = trim(str);
8846        return isEmpty(ts) ? null : ts;
8847    }
8848
8849    /**
8850     * Truncates a String. This will turn
8851     * "Now is the time for all good men" into "Now is the time for".
8852     *
8853     * <p>Specifically:</p>
8854     * <ul>
8855     *   <li>If {@code str} is less than {@code maxWidth} characters
8856     *       long, return it.</li>
8857     *   <li>Else truncate it to {@code substring(str, 0, maxWidth)}.</li>
8858     *   <li>If {@code maxWidth} is less than {@code 0}, throw an
8859     *       {@link IllegalArgumentException}.</li>
8860     *   <li>In no case will it return a String of length greater than
8861     *       {@code maxWidth}.</li>
8862     * </ul>
8863     *
8864     * <pre>
8865     * StringUtils.truncate(null, 0)       = null
8866     * StringUtils.truncate(null, 2)       = null
8867     * StringUtils.truncate("", 4)         = ""
8868     * StringUtils.truncate("abcdefg", 4)  = "abcd"
8869     * StringUtils.truncate("abcdefg", 6)  = "abcdef"
8870     * StringUtils.truncate("abcdefg", 7)  = "abcdefg"
8871     * StringUtils.truncate("abcdefg", 8)  = "abcdefg"
8872     * StringUtils.truncate("abcdefg", -1) = throws an IllegalArgumentException
8873     * </pre>
8874     *
8875     * @param str  the String to truncate, may be null
8876     * @param maxWidth  maximum length of result String, must be positive
8877     * @return truncated String, {@code null} if null String input
8878     * @throws IllegalArgumentException If {@code maxWidth} is less than {@code 0}
8879     * @since 3.5
8880     */
8881    public static String truncate(final String str, final int maxWidth) {
8882        return truncate(str, 0, maxWidth);
8883    }
8884
8885    /**
8886     * Truncates a String. This will turn
8887     * "Now is the time for all good men" into "is the time for all".
8888     *
8889     * <p>Works like {@code truncate(String, int)}, but allows you to specify
8890     * a "left edge" offset.
8891     *
8892     * <p>Specifically:</p>
8893     * <ul>
8894     *   <li>If {@code str} is less than {@code maxWidth} characters
8895     *       long, return it.</li>
8896     *   <li>Else truncate it to {@code substring(str, offset, maxWidth)}.</li>
8897     *   <li>If {@code maxWidth} is less than {@code 0}, throw an
8898     *       {@link IllegalArgumentException}.</li>
8899     *   <li>If {@code offset} is less than {@code 0}, throw an
8900     *       {@link IllegalArgumentException}.</li>
8901     *   <li>In no case will it return a String of length greater than
8902     *       {@code maxWidth}.</li>
8903     * </ul>
8904     *
8905     * <pre>
8906     * StringUtils.truncate(null, 0, 0) = null
8907     * StringUtils.truncate(null, 2, 4) = null
8908     * StringUtils.truncate("", 0, 10) = ""
8909     * StringUtils.truncate("", 2, 10) = ""
8910     * StringUtils.truncate("abcdefghij", 0, 3) = "abc"
8911     * StringUtils.truncate("abcdefghij", 5, 6) = "fghij"
8912     * StringUtils.truncate("raspberry peach", 10, 15) = "peach"
8913     * StringUtils.truncate("abcdefghijklmno", 0, 10) = "abcdefghij"
8914     * StringUtils.truncate("abcdefghijklmno", -1, 10) = throws an IllegalArgumentException
8915     * StringUtils.truncate("abcdefghijklmno", Integer.MIN_VALUE, 10) = throws an IllegalArgumentException
8916     * StringUtils.truncate("abcdefghijklmno", Integer.MIN_VALUE, Integer.MAX_VALUE) = throws an IllegalArgumentException
8917     * StringUtils.truncate("abcdefghijklmno", 0, Integer.MAX_VALUE) = "abcdefghijklmno"
8918     * StringUtils.truncate("abcdefghijklmno", 1, 10) = "bcdefghijk"
8919     * StringUtils.truncate("abcdefghijklmno", 2, 10) = "cdefghijkl"
8920     * StringUtils.truncate("abcdefghijklmno", 3, 10) = "defghijklm"
8921     * StringUtils.truncate("abcdefghijklmno", 4, 10) = "efghijklmn"
8922     * StringUtils.truncate("abcdefghijklmno", 5, 10) = "fghijklmno"
8923     * StringUtils.truncate("abcdefghijklmno", 5, 5) = "fghij"
8924     * StringUtils.truncate("abcdefghijklmno", 5, 3) = "fgh"
8925     * StringUtils.truncate("abcdefghijklmno", 10, 3) = "klm"
8926     * StringUtils.truncate("abcdefghijklmno", 10, Integer.MAX_VALUE) = "klmno"
8927     * StringUtils.truncate("abcdefghijklmno", 13, 1) = "n"
8928     * StringUtils.truncate("abcdefghijklmno", 13, Integer.MAX_VALUE) = "no"
8929     * StringUtils.truncate("abcdefghijklmno", 14, 1) = "o"
8930     * StringUtils.truncate("abcdefghijklmno", 14, Integer.MAX_VALUE) = "o"
8931     * StringUtils.truncate("abcdefghijklmno", 15, 1) = ""
8932     * StringUtils.truncate("abcdefghijklmno", 15, Integer.MAX_VALUE) = ""
8933     * StringUtils.truncate("abcdefghijklmno", Integer.MAX_VALUE, Integer.MAX_VALUE) = ""
8934     * StringUtils.truncate("abcdefghij", 3, -1) = throws an IllegalArgumentException
8935     * StringUtils.truncate("abcdefghij", -2, 4) = throws an IllegalArgumentException
8936     * </pre>
8937     *
8938     * @param str  the String to truncate, may be null
8939     * @param offset  left edge of source String
8940     * @param maxWidth  maximum length of result String, must be positive
8941     * @return truncated String, {@code null} if null String input
8942     * @throws IllegalArgumentException If {@code offset} or {@code maxWidth} is less than {@code 0}
8943     * @since 3.5
8944     */
8945    public static String truncate(final String str, final int offset, final int maxWidth) {
8946        if (offset < 0) {
8947            throw new IllegalArgumentException("offset cannot be negative");
8948        }
8949        if (maxWidth < 0) {
8950            throw new IllegalArgumentException("maxWith cannot be negative");
8951        }
8952        if (str == null) {
8953            return null;
8954        }
8955        if (offset > str.length()) {
8956            return EMPTY;
8957        }
8958        if (str.length() > maxWidth) {
8959            final int ix = Math.min(offset + maxWidth, str.length());
8960            return str.substring(offset, ix);
8961        }
8962        return str.substring(offset);
8963    }
8964
8965    /**
8966     * Uncapitalizes a String, changing the first character to lower case as
8967     * per {@link Character#toLowerCase(int)}. No other characters are changed.
8968     *
8969     * <p>For a word based algorithm, see {@link org.apache.commons.text.WordUtils#uncapitalize(String)}.
8970     * A {@code null} input String returns {@code null}.</p>
8971     *
8972     * <pre>
8973     * StringUtils.uncapitalize(null)  = null
8974     * StringUtils.uncapitalize("")    = ""
8975     * StringUtils.uncapitalize("cat") = "cat"
8976     * StringUtils.uncapitalize("Cat") = "cat"
8977     * StringUtils.uncapitalize("CAT") = "cAT"
8978     * </pre>
8979     *
8980     * @param str the String to uncapitalize, may be null
8981     * @return the uncapitalized String, {@code null} if null String input
8982     * @see org.apache.commons.text.WordUtils#uncapitalize(String)
8983     * @see #capitalize(String)
8984     * @since 2.0
8985     */
8986    public static String uncapitalize(final String str) {
8987        final int strLen = length(str);
8988        if (strLen == 0) {
8989            return str;
8990        }
8991        final int firstCodePoint = str.codePointAt(0);
8992        final int newCodePoint = Character.toLowerCase(firstCodePoint);
8993        if (firstCodePoint == newCodePoint) {
8994            // already uncapitalized
8995            return str;
8996        }
8997        final int[] newCodePoints = str.codePoints().toArray();
8998        newCodePoints[0] = newCodePoint; // copy the first code point
8999        return new String(newCodePoints, 0, newCodePoints.length);
9000    }
9001
9002    /**
9003     * Unwraps a given string from a character.
9004     *
9005     * <pre>
9006     * StringUtils.unwrap(null, null)         = null
9007     * StringUtils.unwrap(null, '\0')         = null
9008     * StringUtils.unwrap(null, '1')          = null
9009     * StringUtils.unwrap("a", 'a')           = "a"
9010     * StringUtils.unwrap("aa", 'a')           = ""
9011     * StringUtils.unwrap("\'abc\'", '\'')    = "abc"
9012     * StringUtils.unwrap("AABabcBAA", 'A')   = "ABabcBA"
9013     * StringUtils.unwrap("A", '#')           = "A"
9014     * StringUtils.unwrap("#A", '#')          = "#A"
9015     * StringUtils.unwrap("A#", '#')          = "A#"
9016     * </pre>
9017     *
9018     * @param str
9019     *          the String to be unwrapped, can be null
9020     * @param wrapChar
9021     *          the character used to unwrap
9022     * @return unwrapped String or the original string
9023     *          if it is not quoted properly with the wrapChar
9024     * @since 3.6
9025     */
9026    public static String unwrap(final String str, final char wrapChar) {
9027        if (isEmpty(str) || wrapChar == CharUtils.NUL || str.length() == 1) {
9028            return str;
9029        }
9030
9031        if (str.charAt(0) == wrapChar && str.charAt(str.length() - 1) == wrapChar) {
9032            final int startIndex = 0;
9033            final int endIndex = str.length() - 1;
9034
9035            return str.substring(startIndex + 1, endIndex);
9036        }
9037
9038        return str;
9039    }
9040
9041    /**
9042     * Unwraps a given string from another string.
9043     *
9044     * <pre>
9045     * StringUtils.unwrap(null, null)         = null
9046     * StringUtils.unwrap(null, "")           = null
9047     * StringUtils.unwrap(null, "1")          = null
9048     * StringUtils.unwrap("a", "a")           = "a"
9049     * StringUtils.unwrap("aa", "a")          = ""
9050     * StringUtils.unwrap("\'abc\'", "\'")    = "abc"
9051     * StringUtils.unwrap("\"abc\"", "\"")    = "abc"
9052     * StringUtils.unwrap("AABabcBAA", "AA")  = "BabcB"
9053     * StringUtils.unwrap("A", "#")           = "A"
9054     * StringUtils.unwrap("#A", "#")          = "#A"
9055     * StringUtils.unwrap("A#", "#")          = "A#"
9056     * </pre>
9057     *
9058     * @param str
9059     *          the String to be unwrapped, can be null
9060     * @param wrapToken
9061     *          the String used to unwrap
9062     * @return unwrapped String or the original string
9063     *          if it is not quoted properly with the wrapToken
9064     * @since 3.6
9065     */
9066    public static String unwrap(final String str, final String wrapToken) {
9067        if (isEmpty(str) || isEmpty(wrapToken) || str.length() < 2 * wrapToken.length()) {
9068            return str;
9069        }
9070
9071        if (Strings.CS.startsWith(str, wrapToken) && Strings.CS.endsWith(str, wrapToken)) {
9072            return str.substring(wrapToken.length(), str.lastIndexOf(wrapToken));
9073        }
9074
9075        return str;
9076    }
9077
9078    /**
9079     * Converts a String to upper case as per {@link String#toUpperCase()}.
9080     *
9081     * <p>A {@code null} input String returns {@code null}.</p>
9082     *
9083     * <pre>
9084     * StringUtils.upperCase(null)  = null
9085     * StringUtils.upperCase("")    = ""
9086     * StringUtils.upperCase("aBc") = "ABC"
9087     * </pre>
9088     *
9089     * <p><strong>Note:</strong> As described in the documentation for {@link String#toUpperCase()},
9090     * the result of this method is affected by the current locale.
9091     * For platform-independent case transformations, the method {@link #upperCase(String, Locale)}
9092     * should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
9093     *
9094     * @param str  the String to upper case, may be null
9095     * @return the upper-cased String, {@code null} if null String input
9096     */
9097    public static String upperCase(final String str) {
9098        if (str == null) {
9099            return null;
9100        }
9101        return str.toUpperCase();
9102    }
9103
9104    /**
9105     * Converts a String to upper case as per {@link String#toUpperCase(Locale)}.
9106     *
9107     * <p>A {@code null} input String returns {@code null}.</p>
9108     *
9109     * <pre>
9110     * StringUtils.upperCase(null, Locale.ENGLISH)  = null
9111     * StringUtils.upperCase("", Locale.ENGLISH)    = ""
9112     * StringUtils.upperCase("aBc", Locale.ENGLISH) = "ABC"
9113     * </pre>
9114     *
9115     * @param str  the String to upper case, may be null
9116     * @param locale  the locale that defines the case transformation rules, must not be null
9117     * @return the upper-cased String, {@code null} if null String input
9118     * @since 2.5
9119     */
9120    public static String upperCase(final String str, final Locale locale) {
9121        if (str == null) {
9122            return null;
9123        }
9124        return str.toUpperCase(LocaleUtils.toLocale(locale));
9125    }
9126
9127    /**
9128     * Returns the string representation of the {@code char} array or null.
9129     *
9130     * @param value the character array.
9131     * @return a String or null
9132     * @see String#valueOf(char[])
9133     * @since 3.9
9134     */
9135    public static String valueOf(final char[] value) {
9136        return value == null ? null : String.valueOf(value);
9137    }
9138
9139    /**
9140     * Wraps a string with a char.
9141     *
9142     * <pre>
9143     * StringUtils.wrap(null, *)        = null
9144     * StringUtils.wrap("", *)          = ""
9145     * StringUtils.wrap("ab", '\0')     = "ab"
9146     * StringUtils.wrap("ab", 'x')      = "xabx"
9147     * StringUtils.wrap("ab", '\'')     = "'ab'"
9148     * StringUtils.wrap("\"ab\"", '\"') = "\"\"ab\"\""
9149     * </pre>
9150     *
9151     * @param str
9152     *            the string to be wrapped, may be {@code null}
9153     * @param wrapWith
9154     *            the char that will wrap {@code str}
9155     * @return the wrapped string, or {@code null} if {@code str == null}
9156     * @since 3.4
9157     */
9158    public static String wrap(final String str, final char wrapWith) {
9159
9160        if (isEmpty(str) || wrapWith == CharUtils.NUL) {
9161            return str;
9162        }
9163
9164        return wrapWith + str + wrapWith;
9165    }
9166
9167    /**
9168     * Wraps a String with another String.
9169     *
9170     * <p>
9171     * A {@code null} input String returns {@code null}.
9172     * </p>
9173     *
9174     * <pre>
9175     * StringUtils.wrap(null, *)         = null
9176     * StringUtils.wrap("", *)           = ""
9177     * StringUtils.wrap("ab", null)      = "ab"
9178     * StringUtils.wrap("ab", "x")       = "xabx"
9179     * StringUtils.wrap("ab", "\"")      = "\"ab\""
9180     * StringUtils.wrap("\"ab\"", "\"")  = "\"\"ab\"\""
9181     * StringUtils.wrap("ab", "'")       = "'ab'"
9182     * StringUtils.wrap("'abcd'", "'")   = "''abcd''"
9183     * StringUtils.wrap("\"abcd\"", "'") = "'\"abcd\"'"
9184     * StringUtils.wrap("'abcd'", "\"")  = "\"'abcd'\""
9185     * </pre>
9186     *
9187     * @param str
9188     *            the String to be wrapper, may be null
9189     * @param wrapWith
9190     *            the String that will wrap str
9191     * @return wrapped String, {@code null} if null String input
9192     * @since 3.4
9193     */
9194    public static String wrap(final String str, final String wrapWith) {
9195
9196        if (isEmpty(str) || isEmpty(wrapWith)) {
9197            return str;
9198        }
9199
9200        return wrapWith.concat(str).concat(wrapWith);
9201    }
9202
9203    /**
9204     * Wraps a string with a char if that char is missing from the start or end of the given string.
9205     *
9206     * <p>A new {@link String} will not be created if {@code str} is already wrapped.</p>
9207     *
9208     * <pre>
9209     * StringUtils.wrapIfMissing(null, *)        = null
9210     * StringUtils.wrapIfMissing("", *)          = ""
9211     * StringUtils.wrapIfMissing("ab", '\0')     = "ab"
9212     * StringUtils.wrapIfMissing("ab", 'x')      = "xabx"
9213     * StringUtils.wrapIfMissing("ab", '\'')     = "'ab'"
9214     * StringUtils.wrapIfMissing("\"ab\"", '\"') = "\"ab\""
9215     * StringUtils.wrapIfMissing("/", '/')  = "/"
9216     * StringUtils.wrapIfMissing("a/b/c", '/')  = "/a/b/c/"
9217     * StringUtils.wrapIfMissing("/a/b/c", '/')  = "/a/b/c/"
9218     * StringUtils.wrapIfMissing("a/b/c/", '/')  = "/a/b/c/"
9219     * </pre>
9220     *
9221     * @param str
9222     *            the string to be wrapped, may be {@code null}
9223     * @param wrapWith
9224     *            the char that will wrap {@code str}
9225     * @return the wrapped string, or {@code null} if {@code str == null}
9226     * @since 3.5
9227     */
9228    public static String wrapIfMissing(final String str, final char wrapWith) {
9229        if (isEmpty(str) || wrapWith == CharUtils.NUL) {
9230            return str;
9231        }
9232        final boolean wrapStart = str.charAt(0) != wrapWith;
9233        final boolean wrapEnd = str.charAt(str.length() - 1) != wrapWith;
9234        if (!wrapStart && !wrapEnd) {
9235            return str;
9236        }
9237
9238        final StringBuilder builder = new StringBuilder(str.length() + 2);
9239        if (wrapStart) {
9240            builder.append(wrapWith);
9241        }
9242        builder.append(str);
9243        if (wrapEnd) {
9244            builder.append(wrapWith);
9245        }
9246        return builder.toString();
9247    }
9248
9249    /**
9250     * Wraps a string with a string if that string is missing from the start or end of the given string.
9251     *
9252     * <p>A new {@link String} will not be created if {@code str} is already wrapped.</p>
9253     *
9254     * <pre>
9255     * StringUtils.wrapIfMissing(null, *)         = null
9256     * StringUtils.wrapIfMissing("", *)           = ""
9257     * StringUtils.wrapIfMissing("ab", null)      = "ab"
9258     * StringUtils.wrapIfMissing("ab", "x")       = "xabx"
9259     * StringUtils.wrapIfMissing("ab", "\"")      = "\"ab\""
9260     * StringUtils.wrapIfMissing("\"ab\"", "\"")  = "\"ab\""
9261     * StringUtils.wrapIfMissing("ab", "'")       = "'ab'"
9262     * StringUtils.wrapIfMissing("'abcd'", "'")   = "'abcd'"
9263     * StringUtils.wrapIfMissing("\"abcd\"", "'") = "'\"abcd\"'"
9264     * StringUtils.wrapIfMissing("'abcd'", "\"")  = "\"'abcd'\""
9265     * StringUtils.wrapIfMissing("/", "/")  = "/"
9266     * StringUtils.wrapIfMissing("a/b/c", "/")  = "/a/b/c/"
9267     * StringUtils.wrapIfMissing("/a/b/c", "/")  = "/a/b/c/"
9268     * StringUtils.wrapIfMissing("a/b/c/", "/")  = "/a/b/c/"
9269     * </pre>
9270     *
9271     * @param str
9272     *            the string to be wrapped, may be {@code null}
9273     * @param wrapWith
9274     *            the string that will wrap {@code str}
9275     * @return the wrapped string, or {@code null} if {@code str == null}
9276     * @since 3.5
9277     */
9278    public static String wrapIfMissing(final String str, final String wrapWith) {
9279        if (isEmpty(str) || isEmpty(wrapWith)) {
9280            return str;
9281        }
9282
9283        final boolean wrapStart = !str.startsWith(wrapWith);
9284        final boolean wrapEnd = !str.endsWith(wrapWith);
9285        if (!wrapStart && !wrapEnd) {
9286            return str;
9287        }
9288
9289        final StringBuilder builder = new StringBuilder(str.length() + wrapWith.length() + wrapWith.length());
9290        if (wrapStart) {
9291            builder.append(wrapWith);
9292        }
9293        builder.append(str);
9294        if (wrapEnd) {
9295            builder.append(wrapWith);
9296        }
9297        return builder.toString();
9298    }
9299
9300    /**
9301     * {@link StringUtils} instances should NOT be constructed in
9302     * standard programming. Instead, the class should be used as
9303     * {@code StringUtils.trim(" foo ");}.
9304     *
9305     * <p>This constructor is public to permit tools that require a JavaBean
9306     * instance to operate.</p>
9307     *
9308     * @deprecated TODO Make private in 4.0.
9309     */
9310    @Deprecated
9311    public StringUtils() {
9312        // empty
9313    }
9314
9315}