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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.lang3.math;
18  
19  import java.lang.reflect.Array;
20  import java.math.BigDecimal;
21  import java.math.BigInteger;
22  
23  import org.apache.commons.lang3.StringUtils;
24  import org.apache.commons.lang3.SystemUtils;
25  import org.apache.commons.lang3.Validate;
26  
27  /**
28   * <p>Provides extra functionality for Java Number classes.</p>
29   *
30   * @since 2.0
31   */
32  public class NumberUtils {
33  
34      /** Reusable Long constant for zero. */
35      public static final Long LONG_ZERO = Long.valueOf(0L);
36      /** Reusable Long constant for one. */
37      public static final Long LONG_ONE = Long.valueOf(1L);
38      /** Reusable Long constant for minus one. */
39      public static final Long LONG_MINUS_ONE = Long.valueOf(-1L);
40      /** Reusable Integer constant for zero. */
41      public static final Integer INTEGER_ZERO = Integer.valueOf(0);
42      /** Reusable Integer constant for one. */
43      public static final Integer INTEGER_ONE = Integer.valueOf(1);
44      /** Reusable Integer constant for minus one. */
45      public static final Integer INTEGER_MINUS_ONE = Integer.valueOf(-1);
46      /** Reusable Short constant for zero. */
47      public static final Short SHORT_ZERO = Short.valueOf((short) 0);
48      /** Reusable Short constant for one. */
49      public static final Short SHORT_ONE = Short.valueOf((short) 1);
50      /** Reusable Short constant for minus one. */
51      public static final Short SHORT_MINUS_ONE = Short.valueOf((short) -1);
52      /** Reusable Byte constant for zero. */
53      public static final Byte BYTE_ZERO = Byte.valueOf((byte) 0);
54      /** Reusable Byte constant for one. */
55      public static final Byte BYTE_ONE = Byte.valueOf((byte) 1);
56      /** Reusable Byte constant for minus one. */
57      public static final Byte BYTE_MINUS_ONE = Byte.valueOf((byte) -1);
58      /** Reusable Double constant for zero. */
59      public static final Double DOUBLE_ZERO = Double.valueOf(0.0d);
60      /** Reusable Double constant for one. */
61      public static final Double DOUBLE_ONE = Double.valueOf(1.0d);
62      /** Reusable Double constant for minus one. */
63      public static final Double DOUBLE_MINUS_ONE = Double.valueOf(-1.0d);
64      /** Reusable Float constant for zero. */
65      public static final Float FLOAT_ZERO = Float.valueOf(0.0f);
66      /** Reusable Float constant for one. */
67      public static final Float FLOAT_ONE = Float.valueOf(1.0f);
68      /** Reusable Float constant for minus one. */
69      public static final Float FLOAT_MINUS_ONE = Float.valueOf(-1.0f);
70  
71      /**
72       * <p><code>NumberUtils</code> instances should NOT be constructed in standard programming.
73       * Instead, the class should be used as <code>NumberUtils.toInt("6");</code>.</p>
74       *
75       * <p>This constructor is public to permit tools that require a JavaBean instance
76       * to operate.</p>
77       */
78      public NumberUtils() {
79          super();
80      }
81  
82      //-----------------------------------------------------------------------
83      /**
84       * <p>Convert a <code>String</code> to an <code>int</code>, returning
85       * <code>zero</code> if the conversion fails.</p>
86       *
87       * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
88       *
89       * <pre>
90       *   NumberUtils.toInt(null) = 0
91       *   NumberUtils.toInt("")   = 0
92       *   NumberUtils.toInt("1")  = 1
93       * </pre>
94       *
95       * @param str  the string to convert, may be null
96       * @return the int represented by the string, or <code>zero</code> if
97       *  conversion fails
98       * @since 2.1
99       */
100     public static int toInt(final String str) {
101         return toInt(str, 0);
102     }
103 
104     /**
105      * <p>Convert a <code>String</code> to an <code>int</code>, returning a
106      * default value if the conversion fails.</p>
107      *
108      * <p>If the string is <code>null</code>, the default value is returned.</p>
109      *
110      * <pre>
111      *   NumberUtils.toInt(null, 1) = 1
112      *   NumberUtils.toInt("", 1)   = 1
113      *   NumberUtils.toInt("1", 0)  = 1
114      * </pre>
115      *
116      * @param str  the string to convert, may be null
117      * @param defaultValue  the default value
118      * @return the int represented by the string, or the default if conversion fails
119      * @since 2.1
120      */
121     public static int toInt(final String str, final int defaultValue) {
122         if(str == null) {
123             return defaultValue;
124         }
125         try {
126             return Integer.parseInt(str);
127         } catch (final NumberFormatException nfe) {
128             return defaultValue;
129         }
130     }
131 
132     /**
133      * <p>Convert a <code>String</code> to a <code>long</code>, returning
134      * <code>zero</code> if the conversion fails.</p>
135      *
136      * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
137      *
138      * <pre>
139      *   NumberUtils.toLong(null) = 0L
140      *   NumberUtils.toLong("")   = 0L
141      *   NumberUtils.toLong("1")  = 1L
142      * </pre>
143      *
144      * @param str  the string to convert, may be null
145      * @return the long represented by the string, or <code>0</code> if
146      *  conversion fails
147      * @since 2.1
148      */
149     public static long toLong(final String str) {
150         return toLong(str, 0L);
151     }
152 
153     /**
154      * <p>Convert a <code>String</code> to a <code>long</code>, returning a
155      * default value if the conversion fails.</p>
156      *
157      * <p>If the string is <code>null</code>, the default value is returned.</p>
158      *
159      * <pre>
160      *   NumberUtils.toLong(null, 1L) = 1L
161      *   NumberUtils.toLong("", 1L)   = 1L
162      *   NumberUtils.toLong("1", 0L)  = 1L
163      * </pre>
164      *
165      * @param str  the string to convert, may be null
166      * @param defaultValue  the default value
167      * @return the long represented by the string, or the default if conversion fails
168      * @since 2.1
169      */
170     public static long toLong(final String str, final long defaultValue) {
171         if (str == null) {
172             return defaultValue;
173         }
174         try {
175             return Long.parseLong(str);
176         } catch (final NumberFormatException nfe) {
177             return defaultValue;
178         }
179     }
180 
181     /**
182      * <p>Convert a <code>String</code> to a <code>float</code>, returning
183      * <code>0.0f</code> if the conversion fails.</p>
184      *
185      * <p>If the string <code>str</code> is <code>null</code>,
186      * <code>0.0f</code> is returned.</p>
187      *
188      * <pre>
189      *   NumberUtils.toFloat(null)   = 0.0f
190      *   NumberUtils.toFloat("")     = 0.0f
191      *   NumberUtils.toFloat("1.5")  = 1.5f
192      * </pre>
193      *
194      * @param str the string to convert, may be <code>null</code>
195      * @return the float represented by the string, or <code>0.0f</code>
196      *  if conversion fails
197      * @since 2.1
198      */
199     public static float toFloat(final String str) {
200         return toFloat(str, 0.0f);
201     }
202 
203     /**
204      * <p>Convert a <code>String</code> to a <code>float</code>, returning a
205      * default value if the conversion fails.</p>
206      *
207      * <p>If the string <code>str</code> is <code>null</code>, the default
208      * value is returned.</p>
209      *
210      * <pre>
211      *   NumberUtils.toFloat(null, 1.1f)   = 1.0f
212      *   NumberUtils.toFloat("", 1.1f)     = 1.1f
213      *   NumberUtils.toFloat("1.5", 0.0f)  = 1.5f
214      * </pre>
215      *
216      * @param str the string to convert, may be <code>null</code>
217      * @param defaultValue the default value
218      * @return the float represented by the string, or defaultValue
219      *  if conversion fails
220      * @since 2.1
221      */
222     public static float toFloat(final String str, final float defaultValue) {
223       if (str == null) {
224           return defaultValue;
225       }
226       try {
227           return Float.parseFloat(str);
228       } catch (final NumberFormatException nfe) {
229           return defaultValue;
230       }
231     }
232 
233     /**
234      * <p>Convert a <code>String</code> to a <code>double</code>, returning
235      * <code>0.0d</code> if the conversion fails.</p>
236      *
237      * <p>If the string <code>str</code> is <code>null</code>,
238      * <code>0.0d</code> is returned.</p>
239      *
240      * <pre>
241      *   NumberUtils.toDouble(null)   = 0.0d
242      *   NumberUtils.toDouble("")     = 0.0d
243      *   NumberUtils.toDouble("1.5")  = 1.5d
244      * </pre>
245      *
246      * @param str the string to convert, may be <code>null</code>
247      * @return the double represented by the string, or <code>0.0d</code>
248      *  if conversion fails
249      * @since 2.1
250      */
251     public static double toDouble(final String str) {
252         return toDouble(str, 0.0d);
253     }
254 
255     /**
256      * <p>Convert a <code>String</code> to a <code>double</code>, returning a
257      * default value if the conversion fails.</p>
258      *
259      * <p>If the string <code>str</code> is <code>null</code>, the default
260      * value is returned.</p>
261      *
262      * <pre>
263      *   NumberUtils.toDouble(null, 1.1d)   = 1.1d
264      *   NumberUtils.toDouble("", 1.1d)     = 1.1d
265      *   NumberUtils.toDouble("1.5", 0.0d)  = 1.5d
266      * </pre>
267      *
268      * @param str the string to convert, may be <code>null</code>
269      * @param defaultValue the default value
270      * @return the double represented by the string, or defaultValue
271      *  if conversion fails
272      * @since 2.1
273      */
274     public static double toDouble(final String str, final double defaultValue) {
275       if (str == null) {
276           return defaultValue;
277       }
278       try {
279           return Double.parseDouble(str);
280       } catch (final NumberFormatException nfe) {
281           return defaultValue;
282       }
283     }
284 
285      //-----------------------------------------------------------------------
286      /**
287      * <p>Convert a <code>String</code> to a <code>byte</code>, returning
288      * <code>zero</code> if the conversion fails.</p>
289      *
290      * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
291      *
292      * <pre>
293      *   NumberUtils.toByte(null) = 0
294      *   NumberUtils.toByte("")   = 0
295      *   NumberUtils.toByte("1")  = 1
296      * </pre>
297      *
298      * @param str  the string to convert, may be null
299      * @return the byte represented by the string, or <code>zero</code> if
300      *  conversion fails
301      * @since 2.5
302      */
303     public static byte toByte(final String str) {
304         return toByte(str, (byte) 0);
305     }
306 
307     /**
308      * <p>Convert a <code>String</code> to a <code>byte</code>, returning a
309      * default value if the conversion fails.</p>
310      *
311      * <p>If the string is <code>null</code>, the default value is returned.</p>
312      *
313      * <pre>
314      *   NumberUtils.toByte(null, 1) = 1
315      *   NumberUtils.toByte("", 1)   = 1
316      *   NumberUtils.toByte("1", 0)  = 1
317      * </pre>
318      *
319      * @param str  the string to convert, may be null
320      * @param defaultValue  the default value
321      * @return the byte represented by the string, or the default if conversion fails
322      * @since 2.5
323      */
324     public static byte toByte(final String str, final byte defaultValue) {
325         if(str == null) {
326             return defaultValue;
327         }
328         try {
329             return Byte.parseByte(str);
330         } catch (final NumberFormatException nfe) {
331             return defaultValue;
332         }
333     }
334 
335     /**
336      * <p>Convert a <code>String</code> to a <code>short</code>, returning
337      * <code>zero</code> if the conversion fails.</p>
338      *
339      * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
340      *
341      * <pre>
342      *   NumberUtils.toShort(null) = 0
343      *   NumberUtils.toShort("")   = 0
344      *   NumberUtils.toShort("1")  = 1
345      * </pre>
346      *
347      * @param str  the string to convert, may be null
348      * @return the short represented by the string, or <code>zero</code> if
349      *  conversion fails
350      * @since 2.5
351      */
352     public static short toShort(final String str) {
353         return toShort(str, (short) 0);
354     }
355 
356     /**
357      * <p>Convert a <code>String</code> to an <code>short</code>, returning a
358      * default value if the conversion fails.</p>
359      *
360      * <p>If the string is <code>null</code>, the default value is returned.</p>
361      *
362      * <pre>
363      *   NumberUtils.toShort(null, 1) = 1
364      *   NumberUtils.toShort("", 1)   = 1
365      *   NumberUtils.toShort("1", 0)  = 1
366      * </pre>
367      *
368      * @param str  the string to convert, may be null
369      * @param defaultValue  the default value
370      * @return the short represented by the string, or the default if conversion fails
371      * @since 2.5
372      */
373     public static short toShort(final String str, final short defaultValue) {
374         if(str == null) {
375             return defaultValue;
376         }
377         try {
378             return Short.parseShort(str);
379         } catch (final NumberFormatException nfe) {
380             return defaultValue;
381         }
382     }
383 
384     //-----------------------------------------------------------------------
385     // must handle Long, Float, Integer, Float, Short,
386     //                  BigDecimal, BigInteger and Byte
387     // useful methods:
388     // Byte.decode(String)
389     // Byte.valueOf(String,int radix)
390     // Byte.valueOf(String)
391     // Double.valueOf(String)
392     // Float.valueOf(String)
393     // Float.valueOf(String)
394     // Integer.valueOf(String,int radix)
395     // Integer.valueOf(String)
396     // Integer.decode(String)
397     // Integer.getInteger(String)
398     // Integer.getInteger(String,int val)
399     // Integer.getInteger(String,Integer val)
400     // Integer.valueOf(String)
401     // Double.valueOf(String)
402     // new Byte(String)
403     // Long.valueOf(String)
404     // Long.getLong(String)
405     // Long.getLong(String,int)
406     // Long.getLong(String,Integer)
407     // Long.valueOf(String,int)
408     // Long.valueOf(String)
409     // Short.valueOf(String)
410     // Short.decode(String)
411     // Short.valueOf(String,int)
412     // Short.valueOf(String)
413     // new BigDecimal(String)
414     // new BigInteger(String)
415     // new BigInteger(String,int radix)
416     // Possible inputs:
417     // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
418     // plus minus everything. Prolly more. A lot are not separable.
419 
420     /**
421      * <p>Turns a string value into a java.lang.Number.</p>
422      *
423      * <p>If the string starts with {@code 0x} or {@code -0x} (lower or upper case) or {@code #} or {@code -#}, it
424      * will be interpreted as a hexadecimal Integer - or Long, if the number of digits after the
425      * prefix is more than 8 - or BigInteger if there are more than 16 digits.
426      * </p>
427      * <p>Then, the value is examined for a type qualifier on the end, i.e. one of
428      * <code>'f','F','d','D','l','L'</code>.  If it is found, it starts
429      * trying to create successively larger types from the type specified
430      * until one is found that can represent the value.</p>
431      *
432      * <p>If a type specifier is not found, it will check for a decimal point
433      * and then try successively larger types from <code>Integer</code> to
434      * <code>BigInteger</code> and from <code>Float</code> to
435     * <code>BigDecimal</code>.</p>
436     *
437      * <p>
438      * Integral values with a leading {@code 0} will be interpreted as octal; the returned number will
439      * be Integer, Long or BigDecimal as appropriate.
440      * </p>
441      *
442      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
443      *
444      * <p>This method does not trim the input string, i.e., strings with leading
445      * or trailing spaces will generate NumberFormatExceptions.</p>
446      *
447      * @param str  String containing a number, may be null
448      * @return Number created from the string (or null if the input is null)
449      * @throws NumberFormatException if the value cannot be converted
450      */
451     public static Number createNumber(final String str) throws NumberFormatException {
452         if (str == null) {
453             return null;
454         }
455         if (StringUtils.isBlank(str)) {
456             throw new NumberFormatException("A blank string is not a valid number");
457         }
458         // Need to deal with all possible hex prefixes here
459         final String[] hex_prefixes = {"0x", "0X", "-0x", "-0X", "#", "-#"};
460         int pfxLen = 0;
461         for(final String pfx : hex_prefixes) {
462             if (str.startsWith(pfx)) {
463                 pfxLen += pfx.length();
464                 break;
465             }
466         }
467         if (pfxLen > 0) { // we have a hex number
468             char firstSigDigit = 0; // strip leading zeroes
469             for(int i = pfxLen; i < str.length(); i++) {
470                 firstSigDigit = str.charAt(i);
471                 if (firstSigDigit == '0') { // count leading zeroes
472                     pfxLen++;
473                 } else {
474                     break;
475                 }
476             }
477             final int hexDigits = str.length() - pfxLen;
478             if (hexDigits > 16 || hexDigits == 16 && firstSigDigit > '7') { // too many for Long
479                 return createBigInteger(str);
480             }
481             if (hexDigits > 8 || hexDigits == 8 && firstSigDigit > '7') { // too many for an int
482                 return createLong(str);
483             }
484             return createInteger(str);
485         }
486         final char lastChar = str.charAt(str.length() - 1);
487         String mant;
488         String dec;
489         String exp;
490         final int decPos = str.indexOf('.');
491         final int expPos = str.indexOf('e') + str.indexOf('E') + 1; // assumes both not present
492         // if both e and E are present, this is caught by the checks on expPos (which prevent IOOBE)
493         // and the parsing which will detect if e or E appear in a number due to using the wrong offset
494 
495         if (decPos > -1) { // there is a decimal point
496             if (expPos > -1) { // there is an exponent
497                 if (expPos < decPos || expPos > str.length()) { // prevents double exponent causing IOOBE
498                     throw new NumberFormatException(str + " is not a valid number.");
499                 }
500                 dec = str.substring(decPos + 1, expPos);
501             } else {
502                 dec = str.substring(decPos + 1);
503             }
504             mant = getMantissa(str, decPos);
505         } else {
506             if (expPos > -1) {
507                 if (expPos > str.length()) { // prevents double exponent causing IOOBE
508                     throw new NumberFormatException(str + " is not a valid number.");
509                 }
510                 mant = getMantissa(str, expPos);
511             } else {
512                 mant = getMantissa(str);
513             }
514             dec = null;
515         }
516         if (!Character.isDigit(lastChar) && lastChar != '.') {
517             if (expPos > -1 && expPos < str.length() - 1) {
518                 exp = str.substring(expPos + 1, str.length() - 1);
519             } else {
520                 exp = null;
521             }
522             //Requesting a specific type..
523             final String numeric = str.substring(0, str.length() - 1);
524             final boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
525             switch (lastChar) {
526                 case 'l' :
527                 case 'L' :
528                     if (dec == null
529                         && exp == null
530                         && (numeric.charAt(0) == '-' && isDigits(numeric.substring(1)) || isDigits(numeric))) {
531                         try {
532                             return createLong(numeric);
533                         } catch (final NumberFormatException nfe) { // NOPMD
534                             // Too big for a long
535                         }
536                         return createBigInteger(numeric);
537 
538                     }
539                     throw new NumberFormatException(str + " is not a valid number.");
540                 case 'f' :
541                 case 'F' :
542                     try {
543                         final Float f = NumberUtils.createFloat(str);
544                         if (!(f.isInfinite() || f.floatValue() == 0.0F && !allZeros)) {
545                             //If it's too big for a float or the float value = 0 and the string
546                             //has non-zeros in it, then float does not have the precision we want
547                             return f;
548                         }
549 
550                     } catch (final NumberFormatException nfe) { // NOPMD
551                         // ignore the bad number
552                     }
553                     //$FALL-THROUGH$
554                 case 'd' :
555                 case 'D' :
556                     try {
557                         final Double d = NumberUtils.createDouble(str);
558                         if (!(d.isInfinite() || d.floatValue() == 0.0D && !allZeros)) {
559                             return d;
560                         }
561                     } catch (final NumberFormatException nfe) { // NOPMD
562                         // ignore the bad number
563                     }
564                     try {
565                         return createBigDecimal(numeric);
566                     } catch (final NumberFormatException e) { // NOPMD
567                         // ignore the bad number
568                     }
569                     //$FALL-THROUGH$
570                 default :
571                     throw new NumberFormatException(str + " is not a valid number.");
572 
573             }
574         }
575         //User doesn't have a preference on the return type, so let's start
576         //small and go from there...
577         if (expPos > -1 && expPos < str.length() - 1) {
578             exp = str.substring(expPos + 1, str.length());
579         } else {
580             exp = null;
581         }
582         if (dec == null && exp == null) { // no decimal point and no exponent
583             //Must be an Integer, Long, Biginteger
584             try {
585                 return createInteger(str);
586             } catch (final NumberFormatException nfe) { // NOPMD
587                 // ignore the bad number
588             }
589             try {
590                 return createLong(str);
591             } catch (final NumberFormatException nfe) { // NOPMD
592                 // ignore the bad number
593             }
594             return createBigInteger(str);
595         }
596 
597         //Must be a Float, Double, BigDecimal
598         final boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
599         try {
600             final Float f = createFloat(str);
601             final Double d = createDouble(str);
602             if (!f.isInfinite()
603                     && !(f.floatValue() == 0.0F && !allZeros)
604                     && f.toString().equals(d.toString())) {
605                 return f;
606             }
607             if (!d.isInfinite() && !(d.doubleValue() == 0.0D && !allZeros)) {
608                 final BigDecimal b = createBigDecimal(str);
609                 if (b.compareTo(BigDecimal.valueOf(d.doubleValue())) == 0) {
610                     return d;
611                 }
612                 return b;
613             }
614         } catch (final NumberFormatException nfe) { // NOPMD
615             // ignore the bad number
616         }
617         return createBigDecimal(str);
618     }
619 
620     /**
621      * <p>Utility method for {@link #createNumber(java.lang.String)}.</p>
622      *
623      * <p>Returns mantissa of the given number.</p>
624      *
625      * @param str the string representation of the number
626      * @return mantissa of the given number
627      */
628     private static String getMantissa(final String str) {
629         return getMantissa(str, str.length());
630     }
631 
632     /**
633      * <p>Utility method for {@link #createNumber(java.lang.String)}.</p>
634      *
635      * <p>Returns mantissa of the given number.</p>
636      *
637      * @param str the string representation of the number
638      * @param stopPos the position of the exponent or decimal point
639      * @return mantissa of the given number
640      */
641     private static String getMantissa(final String str, final int stopPos) {
642         final char firstChar = str.charAt(0);
643         final boolean hasSign = firstChar == '-' || firstChar == '+';
644 
645         return hasSign ? str.substring(1, stopPos) : str.substring(0, stopPos);
646     }
647 
648     /**
649      * <p>Utility method for {@link #createNumber(java.lang.String)}.</p>
650      *
651      * <p>Returns <code>true</code> if s is <code>null</code>.</p>
652      *
653      * @param str  the String to check
654      * @return if it is all zeros or <code>null</code>
655      */
656     private static boolean isAllZeros(final String str) {
657         if (str == null) {
658             return true;
659         }
660         for (int i = str.length() - 1; i >= 0; i--) {
661             if (str.charAt(i) != '0') {
662                 return false;
663             }
664         }
665         return str.length() > 0;
666     }
667 
668     //-----------------------------------------------------------------------
669     /**
670      * <p>Convert a <code>String</code> to a <code>Float</code>.</p>
671      *
672      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
673      *
674      * @param str  a <code>String</code> to convert, may be null
675      * @return converted <code>Float</code> (or null if the input is null)
676      * @throws NumberFormatException if the value cannot be converted
677      */
678     public static Float createFloat(final String str) {
679         if (str == null) {
680             return null;
681         }
682         return Float.valueOf(str);
683     }
684 
685     /**
686      * <p>Convert a <code>String</code> to a <code>Double</code>.</p>
687      *
688      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
689      *
690      * @param str  a <code>String</code> to convert, may be null
691      * @return converted <code>Double</code> (or null if the input is null)
692      * @throws NumberFormatException if the value cannot be converted
693      */
694     public static Double createDouble(final String str) {
695         if (str == null) {
696             return null;
697         }
698         return Double.valueOf(str);
699     }
700 
701     /**
702      * <p>Convert a <code>String</code> to a <code>Integer</code>, handling
703      * hex (0xhhhh) and octal (0dddd) notations.
704      * N.B. a leading zero means octal; spaces are not trimmed.</p>
705      *
706      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
707      *
708      * @param str  a <code>String</code> to convert, may be null
709      * @return converted <code>Integer</code> (or null if the input is null)
710      * @throws NumberFormatException if the value cannot be converted
711      */
712     public static Integer createInteger(final String str) {
713         if (str == null) {
714             return null;
715         }
716         // decode() handles 0xAABD and 0777 (hex and octal) as well.
717         return Integer.decode(str);
718     }
719 
720     /**
721      * <p>Convert a <code>String</code> to a <code>Long</code>;
722      * since 3.1 it handles hex (0Xhhhh) and octal (0ddd) notations.
723      * N.B. a leading zero means octal; spaces are not trimmed.</p>
724      *
725      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
726      *
727      * @param str  a <code>String</code> to convert, may be null
728      * @return converted <code>Long</code> (or null if the input is null)
729      * @throws NumberFormatException if the value cannot be converted
730      */
731     public static Long createLong(final String str) {
732         if (str == null) {
733             return null;
734         }
735         return Long.decode(str);
736     }
737 
738     /**
739      * <p>Convert a <code>String</code> to a <code>BigInteger</code>;
740      * since 3.2 it handles hex (0x or #) and octal (0) notations.</p>
741      *
742      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
743      *
744      * @param str  a <code>String</code> to convert, may be null
745      * @return converted <code>BigInteger</code> (or null if the input is null)
746      * @throws NumberFormatException if the value cannot be converted
747      */
748     public static BigInteger createBigInteger(final String str) {
749         if (str == null) {
750             return null;
751         }
752         int pos = 0; // offset within string
753         int radix = 10;
754         boolean negate = false; // need to negate later?
755         if (str.startsWith("-")) {
756             negate = true;
757             pos = 1;
758         }
759         if (str.startsWith("0x", pos) || str.startsWith("0X", pos)) { // hex
760             radix = 16;
761             pos += 2;
762         } else if (str.startsWith("#", pos)) { // alternative hex (allowed by Long/Integer)
763             radix = 16;
764             pos ++;
765         } else if (str.startsWith("0", pos) && str.length() > pos + 1) { // octal; so long as there are additional digits
766             radix = 8;
767             pos ++;
768         } // default is to treat as decimal
769 
770         final BigInteger value = new BigInteger(str.substring(pos), radix);
771         return negate ? value.negate() : value;
772     }
773 
774     /**
775      * <p>Convert a <code>String</code> to a <code>BigDecimal</code>.</p>
776      *
777      * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
778      *
779      * @param str  a <code>String</code> to convert, may be null
780      * @return converted <code>BigDecimal</code> (or null if the input is null)
781      * @throws NumberFormatException if the value cannot be converted
782      */
783     public static BigDecimal createBigDecimal(final String str) {
784         if (str == null) {
785             return null;
786         }
787         // handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
788         if (StringUtils.isBlank(str)) {
789             throw new NumberFormatException("A blank string is not a valid number");
790         }
791         if (str.trim().startsWith("--")) {
792             // this is protection for poorness in java.lang.BigDecimal.
793             // it accepts this as a legal value, but it does not appear
794             // to be in specification of class. OS X Java parses it to
795             // a wrong value.
796             throw new NumberFormatException(str + " is not a valid number.");
797         }
798         return new BigDecimal(str);
799     }
800 
801     // Min in array
802     //--------------------------------------------------------------------
803     /**
804      * <p>Returns the minimum value in an array.</p>
805      *
806      * @param array  an array, must not be null or empty
807      * @return the minimum value in the array
808      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
809      * @throws IllegalArgumentException if <code>array</code> is empty
810      * @since 3.4 Changed signature from min(long[]) to min(long...)
811      */
812     public static long min(final long... array) {
813         // Validates input
814         validateArray(array);
815 
816         // Finds and returns min
817         long min = array[0];
818         for (int i = 1; i < array.length; i++) {
819             if (array[i] < min) {
820                 min = array[i];
821             }
822         }
823 
824         return min;
825     }
826 
827     /**
828      * <p>Returns the minimum value in an array.</p>
829      *
830      * @param array  an array, must not be null or empty
831      * @return the minimum value in the array
832      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
833      * @throws IllegalArgumentException if <code>array</code> is empty
834      * @since 3.4 Changed signature from min(int[]) to min(int...)
835      */
836     public static int min(final int... array) {
837         // Validates input
838         validateArray(array);
839 
840         // Finds and returns min
841         int min = array[0];
842         for (int j = 1; j < array.length; j++) {
843             if (array[j] < min) {
844                 min = array[j];
845             }
846         }
847 
848         return min;
849     }
850 
851     /**
852      * <p>Returns the minimum value in an array.</p>
853      *
854      * @param array  an array, must not be null or empty
855      * @return the minimum value in the array
856      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
857      * @throws IllegalArgumentException if <code>array</code> is empty
858      * @since 3.4 Changed signature from min(short[]) to min(short...)
859      */
860     public static short min(final short... array) {
861         // Validates input
862         validateArray(array);
863 
864         // Finds and returns min
865         short min = array[0];
866         for (int i = 1; i < array.length; i++) {
867             if (array[i] < min) {
868                 min = array[i];
869             }
870         }
871 
872         return min;
873     }
874 
875     /**
876      * <p>Returns the minimum value in an array.</p>
877      *
878      * @param array  an array, must not be null or empty
879      * @return the minimum value in the array
880      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
881      * @throws IllegalArgumentException if <code>array</code> is empty
882      * @since 3.4 Changed signature from min(byte[]) to min(byte...)
883      */
884     public static byte min(final byte... array) {
885         // Validates input
886         validateArray(array);
887 
888         // Finds and returns min
889         byte min = array[0];
890         for (int i = 1; i < array.length; i++) {
891             if (array[i] < min) {
892                 min = array[i];
893             }
894         }
895 
896         return min;
897     }
898 
899      /**
900      * <p>Returns the minimum value in an array.</p>
901      *
902      * @param array  an array, must not be null or empty
903      * @return the minimum value in the array
904      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
905      * @throws IllegalArgumentException if <code>array</code> is empty
906      * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this method that handles NaN differently
907      * @since 3.4 Changed signature from min(double[]) to min(double...)
908      */
909     public static double min(final double... array) {
910         // Validates input
911         validateArray(array);
912 
913         // Finds and returns min
914         double min = array[0];
915         for (int i = 1; i < array.length; i++) {
916             if (Double.isNaN(array[i])) {
917                 return Double.NaN;
918             }
919             if (array[i] < min) {
920                 min = array[i];
921             }
922         }
923 
924         return min;
925     }
926 
927     /**
928      * <p>Returns the minimum value in an array.</p>
929      *
930      * @param array  an array, must not be null or empty
931      * @return the minimum value in the array
932      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
933      * @throws IllegalArgumentException if <code>array</code> is empty
934      * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this method that handles NaN differently
935      * @since 3.4 Changed signature from min(float[]) to min(float...)
936      */
937     public static float min(final float... array) {
938         // Validates input
939         validateArray(array);
940 
941         // Finds and returns min
942         float min = array[0];
943         for (int i = 1; i < array.length; i++) {
944             if (Float.isNaN(array[i])) {
945                 return Float.NaN;
946             }
947             if (array[i] < min) {
948                 min = array[i];
949             }
950         }
951 
952         return min;
953     }
954 
955     // Max in array
956     //--------------------------------------------------------------------
957     /**
958      * <p>Returns the maximum value in an array.</p>
959      *
960      * @param array  an array, must not be null or empty
961      * @return the maximum value in the array
962      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
963      * @throws IllegalArgumentException if <code>array</code> is empty
964      * @since 3.4 Changed signature from max(long[]) to max(long...)
965      */
966     public static long max(final long... array) {
967         // Validates input
968         validateArray(array);
969 
970         // Finds and returns max
971         long max = array[0];
972         for (int j = 1; j < array.length; j++) {
973             if (array[j] > max) {
974                 max = array[j];
975             }
976         }
977 
978         return max;
979     }
980 
981     /**
982      * <p>Returns the maximum value in an array.</p>
983      *
984      * @param array  an array, must not be null or empty
985      * @return the maximum value in the array
986      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
987      * @throws IllegalArgumentException if <code>array</code> is empty
988      * @since 3.4 Changed signature from max(int[]) to max(int...)
989      */
990     public static int max(final int... array) {
991         // Validates input
992         validateArray(array);
993 
994         // Finds and returns max
995         int max = array[0];
996         for (int j = 1; j < array.length; j++) {
997             if (array[j] > max) {
998                 max = array[j];
999             }
1000         }
1001 
1002         return max;
1003     }
1004 
1005     /**
1006      * <p>Returns the maximum value in an array.</p>
1007      *
1008      * @param array  an array, must not be null or empty
1009      * @return the maximum value in the array
1010      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
1011      * @throws IllegalArgumentException if <code>array</code> is empty
1012      * @since 3.4 Changed signature from max(short[]) to max(short...)
1013      */
1014     public static short max(final short... array) {
1015         // Validates input
1016         validateArray(array);
1017 
1018         // Finds and returns max
1019         short max = array[0];
1020         for (int i = 1; i < array.length; i++) {
1021             if (array[i] > max) {
1022                 max = array[i];
1023             }
1024         }
1025 
1026         return max;
1027     }
1028 
1029     /**
1030      * <p>Returns the maximum value in an array.</p>
1031      *
1032      * @param array  an array, must not be null or empty
1033      * @return the maximum value in the array
1034      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
1035      * @throws IllegalArgumentException if <code>array</code> is empty
1036      * @since 3.4 Changed signature from max(byte[]) to max(byte...)
1037      */
1038     public static byte max(final byte... array) {
1039         // Validates input
1040         validateArray(array);
1041 
1042         // Finds and returns max
1043         byte max = array[0];
1044         for (int i = 1; i < array.length; i++) {
1045             if (array[i] > max) {
1046                 max = array[i];
1047             }
1048         }
1049 
1050         return max;
1051     }
1052 
1053     /**
1054      * <p>Returns the maximum value in an array.</p>
1055      *
1056      * @param array  an array, must not be null or empty
1057      * @return the maximum value in the array
1058      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
1059      * @throws IllegalArgumentException if <code>array</code> is empty
1060      * @see IEEE754rUtils#max(double[]) IEEE754rUtils for a version of this method that handles NaN differently
1061      * @since 3.4 Changed signature from max(double[]) to max(double...)
1062      */
1063     public static double max(final double... array) {
1064         // Validates input
1065         validateArray(array);
1066 
1067         // Finds and returns max
1068         double max = array[0];
1069         for (int j = 1; j < array.length; j++) {
1070             if (Double.isNaN(array[j])) {
1071                 return Double.NaN;
1072             }
1073             if (array[j] > max) {
1074                 max = array[j];
1075             }
1076         }
1077 
1078         return max;
1079     }
1080 
1081     /**
1082      * <p>Returns the maximum value in an array.</p>
1083      *
1084      * @param array  an array, must not be null or empty
1085      * @return the maximum value in the array
1086      * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
1087      * @throws IllegalArgumentException if <code>array</code> is empty
1088      * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this method that handles NaN differently
1089      * @since 3.4 Changed signature from max(float[]) to max(float...)
1090      */
1091     public static float max(final float... array) {
1092         // Validates input
1093         validateArray(array);
1094 
1095         // Finds and returns max
1096         float max = array[0];
1097         for (int j = 1; j < array.length; j++) {
1098             if (Float.isNaN(array[j])) {
1099                 return Float.NaN;
1100             }
1101             if (array[j] > max) {
1102                 max = array[j];
1103             }
1104         }
1105 
1106         return max;
1107     }
1108 
1109     /**
1110      * Checks if the specified array is neither null nor empty.
1111      *
1112      * @param array  the array to check
1113      * @throws IllegalArgumentException if {@code array} is either {@code null} or empty
1114      */
1115     private static void validateArray(final Object array) {
1116         Validate.isTrue(array != null, "The Array must not be null");
1117         Validate.isTrue(Array.getLength(array) != 0, "Array cannot be empty.");
1118     }
1119 
1120     // 3 param min
1121     //-----------------------------------------------------------------------
1122     /**
1123      * <p>Gets the minimum of three <code>long</code> values.</p>
1124      *
1125      * @param a  value 1
1126      * @param b  value 2
1127      * @param c  value 3
1128      * @return  the smallest of the values
1129      */
1130     public static long min(long a, final long b, final long c) {
1131         if (b < a) {
1132             a = b;
1133         }
1134         if (c < a) {
1135             a = c;
1136         }
1137         return a;
1138     }
1139 
1140     /**
1141      * <p>Gets the minimum of three <code>int</code> values.</p>
1142      *
1143      * @param a  value 1
1144      * @param b  value 2
1145      * @param c  value 3
1146      * @return  the smallest of the values
1147      */
1148     public static int min(int a, final int b, final int c) {
1149         if (b < a) {
1150             a = b;
1151         }
1152         if (c < a) {
1153             a = c;
1154         }
1155         return a;
1156     }
1157 
1158     /**
1159      * <p>Gets the minimum of three <code>short</code> values.</p>
1160      *
1161      * @param a  value 1
1162      * @param b  value 2
1163      * @param c  value 3
1164      * @return  the smallest of the values
1165      */
1166     public static short min(short a, final short b, final short c) {
1167         if (b < a) {
1168             a = b;
1169         }
1170         if (c < a) {
1171             a = c;
1172         }
1173         return a;
1174     }
1175 
1176     /**
1177      * <p>Gets the minimum of three <code>byte</code> values.</p>
1178      *
1179      * @param a  value 1
1180      * @param b  value 2
1181      * @param c  value 3
1182      * @return  the smallest of the values
1183      */
1184     public static byte min(byte a, final byte b, final byte c) {
1185         if (b < a) {
1186             a = b;
1187         }
1188         if (c < a) {
1189             a = c;
1190         }
1191         return a;
1192     }
1193 
1194     /**
1195      * <p>Gets the minimum of three <code>double</code> values.</p>
1196      *
1197      * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1198      * returned. Infinity is handled.</p>
1199      *
1200      * @param a  value 1
1201      * @param b  value 2
1202      * @param c  value 3
1203      * @return  the smallest of the values
1204      * @see IEEE754rUtils#min(double, double, double) for a version of this method that handles NaN differently
1205      */
1206     public static double min(final double a, final double b, final double c) {
1207         return Math.min(Math.min(a, b), c);
1208     }
1209 
1210     /**
1211      * <p>Gets the minimum of three <code>float</code> values.</p>
1212      *
1213      * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1214      * returned. Infinity is handled.</p>
1215      *
1216      * @param a  value 1
1217      * @param b  value 2
1218      * @param c  value 3
1219      * @return  the smallest of the values
1220      * @see IEEE754rUtils#min(float, float, float) for a version of this method that handles NaN differently
1221      */
1222     public static float min(final float a, final float b, final float c) {
1223         return Math.min(Math.min(a, b), c);
1224     }
1225 
1226     // 3 param max
1227     //-----------------------------------------------------------------------
1228     /**
1229      * <p>Gets the maximum of three <code>long</code> values.</p>
1230      *
1231      * @param a  value 1
1232      * @param b  value 2
1233      * @param c  value 3
1234      * @return  the largest of the values
1235      */
1236     public static long max(long a, final long b, final long c) {
1237         if (b > a) {
1238             a = b;
1239         }
1240         if (c > a) {
1241             a = c;
1242         }
1243         return a;
1244     }
1245 
1246     /**
1247      * <p>Gets the maximum of three <code>int</code> values.</p>
1248      *
1249      * @param a  value 1
1250      * @param b  value 2
1251      * @param c  value 3
1252      * @return  the largest of the values
1253      */
1254     public static int max(int a, final int b, final int c) {
1255         if (b > a) {
1256             a = b;
1257         }
1258         if (c > a) {
1259             a = c;
1260         }
1261         return a;
1262     }
1263 
1264     /**
1265      * <p>Gets the maximum of three <code>short</code> values.</p>
1266      *
1267      * @param a  value 1
1268      * @param b  value 2
1269      * @param c  value 3
1270      * @return  the largest of the values
1271      */
1272     public static short max(short a, final short b, final short c) {
1273         if (b > a) {
1274             a = b;
1275         }
1276         if (c > a) {
1277             a = c;
1278         }
1279         return a;
1280     }
1281 
1282     /**
1283      * <p>Gets the maximum of three <code>byte</code> values.</p>
1284      *
1285      * @param a  value 1
1286      * @param b  value 2
1287      * @param c  value 3
1288      * @return  the largest of the values
1289      */
1290     public static byte max(byte a, final byte b, final byte c) {
1291         if (b > a) {
1292             a = b;
1293         }
1294         if (c > a) {
1295             a = c;
1296         }
1297         return a;
1298     }
1299 
1300     /**
1301      * <p>Gets the maximum of three <code>double</code> values.</p>
1302      *
1303      * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1304      * returned. Infinity is handled.</p>
1305      *
1306      * @param a  value 1
1307      * @param b  value 2
1308      * @param c  value 3
1309      * @return  the largest of the values
1310      * @see IEEE754rUtils#max(double, double, double) for a version of this method that handles NaN differently
1311      */
1312     public static double max(final double a, final double b, final double c) {
1313         return Math.max(Math.max(a, b), c);
1314     }
1315 
1316     /**
1317      * <p>Gets the maximum of three <code>float</code> values.</p>
1318      *
1319      * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1320      * returned. Infinity is handled.</p>
1321      *
1322      * @param a  value 1
1323      * @param b  value 2
1324      * @param c  value 3
1325      * @return  the largest of the values
1326      * @see IEEE754rUtils#max(float, float, float) for a version of this method that handles NaN differently
1327      */
1328     public static float max(final float a, final float b, final float c) {
1329         return Math.max(Math.max(a, b), c);
1330     }
1331 
1332     //-----------------------------------------------------------------------
1333     /**
1334      * <p>Checks whether the <code>String</code> contains only
1335      * digit characters.</p>
1336      *
1337      * <p><code>Null</code> and empty String will return
1338      * <code>false</code>.</p>
1339      *
1340      * @param str  the <code>String</code> to check
1341      * @return <code>true</code> if str contains only Unicode numeric
1342      */
1343     public static boolean isDigits(final String str) {
1344         return StringUtils.isNumeric(str);
1345     }
1346 
1347     /**
1348      * <p>Checks whether the String a valid Java number.</p>
1349      *
1350      * <p>Valid numbers include hexadecimal marked with the <code>0x</code> or
1351      * <code>0X</code> qualifier, octal numbers, scientific notation and
1352      * numbers marked with a type qualifier (e.g. 123L).</p>
1353      *
1354      * <p>Non-hexadecimal strings beginning with a leading zero are
1355      * treated as octal values. Thus the string <code>09</code> will return
1356      * <code>false</code>, since <code>9</code> is not a valid octal value.
1357      * However, numbers beginning with {@code 0.} are treated as decimal.</p>
1358      *
1359      * <p><code>null</code> and empty/blank {@code String} will return
1360      * <code>false</code>.</p>
1361      *
1362      * <p>Note, {@link #createNumber(String)} should return a number for every
1363      * input resulting in <code>true</code>.</p>
1364      *
1365      * @param str  the <code>String</code> to check
1366      * @return <code>true</code> if the string is a correctly formatted number
1367      * @since 3.3 the code supports hex {@code 0Xhhh} an
1368      *        octal {@code 0ddd} validation
1369      * @deprecated This feature will be removed in Lang 4.0,
1370      *             use {@link NumberUtils#isCreatable(String)} instead
1371      */
1372     @Deprecated
1373     public static boolean isNumber(final String str) {
1374         return isCreatable(str);
1375     }
1376 
1377     /**
1378      * <p>Checks whether the String a valid Java number.</p>
1379      *
1380      * <p>Valid numbers include hexadecimal marked with the <code>0x</code> or
1381      * <code>0X</code> qualifier, octal numbers, scientific notation and
1382      * numbers marked with a type qualifier (e.g. 123L).</p>
1383      *
1384      * <p>Non-hexadecimal strings beginning with a leading zero are
1385      * treated as octal values. Thus the string <code>09</code> will return
1386      * <code>false</code>, since <code>9</code> is not a valid octal value.
1387      * However, numbers beginning with {@code 0.} are treated as decimal.</p>
1388      *
1389      * <p><code>null</code> and empty/blank {@code String} will return
1390      * <code>false</code>.</p>
1391      *
1392      * <p>Note, {@link #createNumber(String)} should return a number for every
1393      * input resulting in <code>true</code>.</p>
1394      *
1395      * @param str  the <code>String</code> to check
1396      * @return <code>true</code> if the string is a correctly formatted number
1397      * @since 3.5 the code supports the "+" suffix on numbers except for integers in Java 1.6
1398      */
1399     public static boolean isCreatable(final String str) {
1400         if (StringUtils.isEmpty(str)) {
1401             return false;
1402         }
1403         final char[] chars = str.toCharArray();
1404         int sz = chars.length;
1405         boolean hasExp = false;
1406         boolean hasDecPoint = false;
1407         boolean allowSigns = false;
1408         boolean foundDigit = false;
1409         // deal with any possible sign up front
1410         final int start = chars[0] == '-' || chars[0] == '+' ? 1 : 0;
1411         final boolean hasLeadingPlusSign = start == 1 && chars[0] == '+';
1412         if (sz > start + 1 && chars[start] == '0') { // leading 0
1413             if (chars[start + 1] == 'x' || chars[start + 1] == 'X') { // leading 0x/0X
1414                 int i = start + 2;
1415                 if (i == sz) {
1416                     return false; // str == "0x"
1417                 }
1418                 // checking hex (it can't be anything else)
1419                 for (; i < chars.length; i++) {
1420                     if ((chars[i] < '0' || chars[i] > '9')
1421                         && (chars[i] < 'a' || chars[i] > 'f')
1422                         && (chars[i] < 'A' || chars[i] > 'F')) {
1423                         return false;
1424                     }
1425                 }
1426                 return true;
1427            } else if (Character.isDigit(chars[start + 1])) {
1428                // leading 0, but not hex, must be octal
1429                int i = start + 1;
1430                for (; i < chars.length; i++) {
1431                    if (chars[i] < '0' || chars[i] > '7') {
1432                        return false;
1433                    }
1434                }
1435                return true;
1436            }
1437         }
1438         sz--; // don't want to loop to the last char, check it afterwords
1439               // for type qualifiers
1440         int i = start;
1441         // loop to the next to last char or to the last char if we need another digit to
1442         // make a valid number (e.g. chars[0..5] = "1234E")
1443         while (i < sz || i < sz + 1 && allowSigns && !foundDigit) {
1444             if (chars[i] >= '0' && chars[i] <= '9') {
1445                 foundDigit = true;
1446                 allowSigns = false;
1447 
1448             } else if (chars[i] == '.') {
1449                 if (hasDecPoint || hasExp) {
1450                     // two decimal points or dec in exponent
1451                     return false;
1452                 }
1453                 hasDecPoint = true;
1454             } else if (chars[i] == 'e' || chars[i] == 'E') {
1455                 // we've already taken care of hex.
1456                 if (hasExp) {
1457                     // two E's
1458                     return false;
1459                 }
1460                 if (!foundDigit) {
1461                     return false;
1462                 }
1463                 hasExp = true;
1464                 allowSigns = true;
1465             } else if (chars[i] == '+' || chars[i] == '-') {
1466                 if (!allowSigns) {
1467                     return false;
1468                 }
1469                 allowSigns = false;
1470                 foundDigit = false; // we need a digit after the E
1471             } else {
1472                 return false;
1473             }
1474             i++;
1475         }
1476         if (i < chars.length) {
1477             if (chars[i] >= '0' && chars[i] <= '9') {
1478                 if (SystemUtils.IS_JAVA_1_6 && hasLeadingPlusSign && !hasDecPoint) {
1479                     return false;
1480                 }
1481                 // no type qualifier, OK
1482                 return true;
1483             }
1484             if (chars[i] == 'e' || chars[i] == 'E') {
1485                 // can't have an E at the last byte
1486                 return false;
1487             }
1488             if (chars[i] == '.') {
1489                 if (hasDecPoint || hasExp) {
1490                     // two decimal points or dec in exponent
1491                     return false;
1492                 }
1493                 // single trailing decimal point after non-exponent is ok
1494                 return foundDigit;
1495             }
1496             if (!allowSigns
1497                 && (chars[i] == 'd'
1498                     || chars[i] == 'D'
1499                     || chars[i] == 'f'
1500                     || chars[i] == 'F')) {
1501                 return foundDigit;
1502             }
1503             if (chars[i] == 'l'
1504                 || chars[i] == 'L') {
1505                 // not allowing L with an exponent or decimal point
1506                 return foundDigit && !hasExp && !hasDecPoint;
1507             }
1508             // last character is illegal
1509             return false;
1510         }
1511         // allowSigns is true iff the val ends in 'E'
1512         // found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
1513         return !allowSigns && foundDigit;
1514     }
1515 
1516     /**
1517      * <p>Checks whether the given String is a parsable number.</p>
1518      *
1519      * <p>Parsable numbers include those Strings understood by {@link Integer#parseInt(String)},
1520      * {@link Long#parseLong(String)}, {@link Float#parseFloat(String)} or
1521      * {@link Double#parseDouble(String)}. This method can be used instead of catching {@link java.text.ParseException}
1522      * when calling one of those methods.</p>
1523      *
1524      * <p>Hexadecimal and scientific notations are <strong>not</strong> considered parsable.
1525      * See {@link #isCreatable(String)} on those cases.</p>
1526      *
1527      * <p>{@code Null} and empty String will return <code>false</code>.</p>
1528      *
1529      * @param str the String to check.
1530      * @return {@code true} if the string is a parsable number.
1531      * @since 3.4
1532      */
1533     public static boolean isParsable(final String str) {
1534         if (StringUtils.isEmpty(str)) {
1535             return false;
1536         }
1537         if (str.charAt(str.length() - 1) == '.') {
1538             return false;
1539         }
1540         if (str.charAt(0) == '-') {
1541             if (str.length() == 1) {
1542                 return false;
1543             }
1544             return withDecimalsParsing(str, 1);
1545         }
1546         return withDecimalsParsing(str, 0);
1547     }
1548 
1549     private static boolean withDecimalsParsing(final String str, final int beginIdx) {
1550         int decimalPoints = 0;
1551         for (int i = beginIdx; i < str.length(); i++) {
1552             final boolean isDecimalPoint = str.charAt(i) == '.';
1553             if (isDecimalPoint) {
1554                 decimalPoints++;
1555             }
1556             if (decimalPoints > 1) {
1557                 return false;
1558             }
1559             if (!isDecimalPoint && !Character.isDigit(str.charAt(i))) {
1560                 return false;
1561             }
1562         }
1563         return true;
1564     }
1565 
1566     /**
1567      * <p>Compares two {@code int} values numerically. This is the same functionality as provided in Java 7.</p>
1568      *
1569      * @param x the first {@code int} to compare
1570      * @param y the second {@code int} to compare
1571      * @return the value {@code 0} if {@code x == y};
1572      *         a value less than {@code 0} if {@code x < y}; and
1573      *         a value greater than {@code 0} if {@code x > y}
1574      * @since 3.4
1575      */
1576     public static int compare(final int x, final int y) {
1577         if (x == y) {
1578             return 0;
1579         }
1580         return x < y ? -1 : 1;
1581     }
1582 
1583     /**
1584      * <p>Compares to {@code long} values numerically. This is the same functionality as provided in Java 7.</p>
1585      *
1586      * @param x the first {@code long} to compare
1587      * @param y the second {@code long} to compare
1588      * @return the value {@code 0} if {@code x == y};
1589      *         a value less than {@code 0} if {@code x < y}; and
1590      *         a value greater than {@code 0} if {@code x > y}
1591      * @since 3.4
1592      */
1593     public static int compare(final long x, final long y) {
1594         if (x == y) {
1595             return 0;
1596         }
1597         return x < y ? -1 : 1;
1598     }
1599 
1600     /**
1601      * <p>Compares to {@code short} values numerically. This is the same functionality as provided in Java 7.</p>
1602      *
1603      * @param x the first {@code short} to compare
1604      * @param y the second {@code short} to compare
1605      * @return the value {@code 0} if {@code x == y};
1606      *         a value less than {@code 0} if {@code x < y}; and
1607      *         a value greater than {@code 0} if {@code x > y}
1608      * @since 3.4
1609      */
1610     public static int compare(final short x, final short y) {
1611         if (x == y) {
1612             return 0;
1613         }
1614         return x < y ? -1 : 1;
1615     }
1616 
1617     /**
1618      * <p>Compares two {@code byte} values numerically. This is the same functionality as provided in Java 7.</p>
1619      *
1620      * @param x the first {@code byte} to compare
1621      * @param y the second {@code byte} to compare
1622      * @return the value {@code 0} if {@code x == y};
1623      *         a value less than {@code 0} if {@code x < y}; and
1624      *         a value greater than {@code 0} if {@code x > y}
1625      * @since 3.4
1626      */
1627     public static int compare(final byte x, final byte y) {
1628         return x - y;
1629     }
1630 }