001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     * 
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.lang.math;
018    
019    import java.math.BigDecimal;
020    import java.math.BigInteger;
021    
022    import org.apache.commons.lang.StringUtils;
023    
024    /**
025     * <p>Provides extra functionality for Java Number classes.</p>
026     *
027     * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
028     * @author Stephen Colebourne
029     * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
030     * @author Eric Pugh
031     * @author Phil Steitz
032     * @author Matthew Hawthorne
033     * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
034     * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
035     * @since 2.0
036     * @version $Id: NumberUtils.java 609475 2008-01-06 23:58:59Z bayard $
037     */
038    public class NumberUtils {
039        
040        /** Reusable Long constant for zero. */
041        public static final Long LONG_ZERO = new Long(0L);
042        /** Reusable Long constant for one. */
043        public static final Long LONG_ONE = new Long(1L);
044        /** Reusable Long constant for minus one. */
045        public static final Long LONG_MINUS_ONE = new Long(-1L);
046        /** Reusable Integer constant for zero. */
047        public static final Integer INTEGER_ZERO = new Integer(0);
048        /** Reusable Integer constant for one. */
049        public static final Integer INTEGER_ONE = new Integer(1);
050        /** Reusable Integer constant for minus one. */
051        public static final Integer INTEGER_MINUS_ONE = new Integer(-1);
052        /** Reusable Short constant for zero. */
053        public static final Short SHORT_ZERO = new Short((short) 0);
054        /** Reusable Short constant for one. */
055        public static final Short SHORT_ONE = new Short((short) 1);
056        /** Reusable Short constant for minus one. */
057        public static final Short SHORT_MINUS_ONE = new Short((short) -1);
058        /** Reusable Byte constant for zero. */
059        public static final Byte BYTE_ZERO = new Byte((byte) 0);
060        /** Reusable Byte constant for one. */
061        public static final Byte BYTE_ONE = new Byte((byte) 1);
062        /** Reusable Byte constant for minus one. */
063        public static final Byte BYTE_MINUS_ONE = new Byte((byte) -1);
064        /** Reusable Double constant for zero. */
065        public static final Double DOUBLE_ZERO = new Double(0.0d);
066        /** Reusable Double constant for one. */
067        public static final Double DOUBLE_ONE = new Double(1.0d);
068        /** Reusable Double constant for minus one. */
069        public static final Double DOUBLE_MINUS_ONE = new Double(-1.0d);
070        /** Reusable Float constant for zero. */
071        public static final Float FLOAT_ZERO = new Float(0.0f);
072        /** Reusable Float constant for one. */
073        public static final Float FLOAT_ONE = new Float(1.0f);
074        /** Reusable Float constant for minus one. */
075        public static final Float FLOAT_MINUS_ONE = new Float(-1.0f);
076    
077        /**
078         * <p><code>NumberUtils</code> instances should NOT be constructed in standard programming.
079         * Instead, the class should be used as <code>NumberUtils.stringToInt("6");</code>.</p>
080         *
081         * <p>This constructor is public to permit tools that require a JavaBean instance
082         * to operate.</p>
083         */
084        public NumberUtils() {
085            super();
086        }
087    
088        //-----------------------------------------------------------------------
089        /**
090         * <p>Convert a <code>String</code> to an <code>int</code>, returning
091         * <code>zero</code> if the conversion fails.</p>
092         *
093         * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
094         * 
095         * <pre>
096         *   NumberUtils.stringToInt(null) = 0
097         *   NumberUtils.stringToInt("")   = 0
098         *   NumberUtils.stringToInt("1")  = 1
099         * </pre>
100         *
101         * @param str  the string to convert, may be null
102         * @return the int represented by the string, or <code>zero</code> if
103         *  conversion fails
104         * @deprecated Use {@link #toInt(String)}
105         *  This method will be removed in Commons Lang 3.0
106         */
107        public static int stringToInt(String str) {
108            return toInt(str);
109        }
110    
111        /**
112         * <p>Convert a <code>String</code> to an <code>int</code>, returning
113         * <code>zero</code> if the conversion fails.</p>
114         *
115         * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
116         *
117         * <pre>
118         *   NumberUtils.toInt(null) = 0
119         *   NumberUtils.toInt("")   = 0
120         *   NumberUtils.toInt("1")  = 1
121         * </pre>
122         *
123         * @param str  the string to convert, may be null
124         * @return the int represented by the string, or <code>zero</code> if
125         *  conversion fails
126         * @since 2.1
127         */
128        public static int toInt(String str) {
129            return toInt(str, 0);
130        }
131    
132        /**
133         * <p>Convert a <code>String</code> to an <code>int</code>, returning a
134         * default value if the conversion fails.</p>
135         *
136         * <p>If the string is <code>null</code>, the default value is returned.</p>
137         * 
138         * <pre>
139         *   NumberUtils.stringToInt(null, 1) = 1
140         *   NumberUtils.stringToInt("", 1)   = 1
141         *   NumberUtils.stringToInt("1", 0)  = 1
142         * </pre>
143         *
144         * @param str  the string to convert, may be null
145         * @param defaultValue  the default value
146         * @return the int represented by the string, or the default if conversion fails
147         * @deprecated Use {@link #toInt(String, int)}
148         *  This method will be removed in Commons Lang 3.0
149         */
150        public static int stringToInt(String str, int defaultValue) {
151            return toInt(str, defaultValue);
152        }
153    
154        /**
155         * <p>Convert a <code>String</code> to an <code>int</code>, returning a
156         * default value if the conversion fails.</p>
157         *
158         * <p>If the string is <code>null</code>, the default value is returned.</p>
159         *
160         * <pre>
161         *   NumberUtils.toInt(null, 1) = 1
162         *   NumberUtils.toInt("", 1)   = 1
163         *   NumberUtils.toInt("1", 0)  = 1
164         * </pre>
165         *
166         * @param str  the string to convert, may be null
167         * @param defaultValue  the default value
168         * @return the int represented by the string, or the default if conversion fails
169         * @since 2.1
170         */
171        public static int toInt(String str, int defaultValue) {
172            if(str == null) {
173                return defaultValue;
174            }
175            try {
176                return Integer.parseInt(str);
177            } catch (NumberFormatException nfe) {
178                return defaultValue;
179            }
180        }
181    
182        /**
183         * <p>Convert a <code>String</code> to a <code>long</code>, returning
184         * <code>zero</code> if the conversion fails.</p>
185         *
186         * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
187         *
188         * <pre>
189         *   NumberUtils.toLong(null) = 0L
190         *   NumberUtils.toLong("")   = 0L
191         *   NumberUtils.toLong("1")  = 1L
192         * </pre>
193         *
194         * @param str  the string to convert, may be null
195         * @return the long represented by the string, or <code>0</code> if
196         *  conversion fails
197         * @since 2.1
198         */
199        public static long toLong(String str) {
200            return toLong(str, 0L);
201        }
202    
203        /**
204         * <p>Convert a <code>String</code> to a <code>long</code>, returning a
205         * default value if the conversion fails.</p>
206         *
207         * <p>If the string is <code>null</code>, the default value is returned.</p>
208         *
209         * <pre>
210         *   NumberUtils.toLong(null, 1L) = 1L
211         *   NumberUtils.toLong("", 1L)   = 1L
212         *   NumberUtils.toLong("1", 0L)  = 1L
213         * </pre>
214         *
215         * @param str  the string to convert, may be null
216         * @param defaultValue  the default value
217         * @return the long represented by the string, or the default if conversion fails
218         * @since 2.1
219         */
220        public static long toLong(String str, long defaultValue) {
221            if (str == null) {
222                return defaultValue;
223            }
224            try {
225                return Long.parseLong(str);
226            } catch (NumberFormatException nfe) {
227                return defaultValue;
228            }
229        }
230    
231        /**
232         * <p>Convert a <code>String</code> to a <code>float</code>, returning
233         * <code>0.0f</code> if the conversion fails.</p>
234         *
235         * <p>If the string <code>str</code> is <code>null</code>,
236         * <code>0.0f</code> is returned.</p>
237         *
238         * <pre>
239         *   NumberUtils.toFloat(null)   = 0.0f
240         *   NumberUtils.toFloat("")     = 0.0f
241         *   NumberUtils.toFloat("1.5")  = 1.5f
242         * </pre>
243         *
244         * @param str the string to convert, may be <code>null</code>
245         * @return the float represented by the string, or <code>0.0f</code>
246         *  if conversion fails
247         * @since 2.1
248         */
249        public static float toFloat(String str) {
250            return toFloat(str, 0.0f);
251        }
252    
253        /**
254         * <p>Convert a <code>String</code> to a <code>float</code>, returning a
255         * default value if the conversion fails.</p>
256         *
257         * <p>If the string <code>str</code> is <code>null</code>, the default
258         * value is returned.</p>
259         *
260         * <pre>
261         *   NumberUtils.toFloat(null, 1.1f)   = 1.0f
262         *   NumberUtils.toFloat("", 1.1f)     = 1.1f
263         *   NumberUtils.toFloat("1.5", 0.0f)  = 1.5f
264         * </pre>
265         *
266         * @param str the string to convert, may be <code>null</code>
267         * @param defaultValue the default value
268         * @return the float represented by the string, or defaultValue
269         *  if conversion fails
270         * @since 2.1
271         */
272        public static float toFloat(String str, float defaultValue) {
273          if (str == null) {
274              return defaultValue;
275          }     
276          try {
277              return Float.parseFloat(str);
278          } catch (NumberFormatException nfe) {
279              return defaultValue;
280          }
281        }
282    
283        /**
284         * <p>Convert a <code>String</code> to a <code>double</code>, returning
285         * <code>0.0d</code> if the conversion fails.</p>
286         *
287         * <p>If the string <code>str</code> is <code>null</code>,
288         * <code>0.0d</code> is returned.</p>
289         *
290         * <pre>
291         *   NumberUtils.toDouble(null)   = 0.0d
292         *   NumberUtils.toDouble("")     = 0.0d
293         *   NumberUtils.toDouble("1.5")  = 1.5d
294         * </pre>
295         *
296         * @param str the string to convert, may be <code>null</code>
297         * @return the double represented by the string, or <code>0.0d</code>
298         *  if conversion fails
299         * @since 2.1
300         */
301        public static double toDouble(String str) {
302            return toDouble(str, 0.0d);
303        }
304    
305        /**
306         * <p>Convert a <code>String</code> to a <code>double</code>, returning a
307         * default value if the conversion fails.</p>
308         *
309         * <p>If the string <code>str</code> is <code>null</code>, the default
310         * value is returned.</p>
311         *
312         * <pre>
313         *   NumberUtils.toDouble(null, 1.1d)   = 1.1d
314         *   NumberUtils.toDouble("", 1.1d)     = 1.1d
315         *   NumberUtils.toDouble("1.5", 0.0d)  = 1.5d
316         * </pre>
317         *
318         * @param str the string to convert, may be <code>null</code>
319         * @param defaultValue the default value
320         * @return the double represented by the string, or defaultValue
321         *  if conversion fails
322         * @since 2.1
323         */
324        public static double toDouble(String str, double defaultValue) {
325          if (str == null) {
326              return defaultValue;
327          }
328          try {
329              return Double.parseDouble(str);
330          } catch (NumberFormatException nfe) {
331              return defaultValue;
332          }
333        }
334    
335        //-----------------------------------------------------------------------
336        // must handle Long, Float, Integer, Float, Short,
337        //                  BigDecimal, BigInteger and Byte
338        // useful methods:
339        // Byte.decode(String)
340        // Byte.valueOf(String,int radix)
341        // Byte.valueOf(String)
342        // Double.valueOf(String)
343        // Float.valueOf(String)
344        // new Float(String)
345        // Integer.valueOf(String,int radix)
346        // Integer.valueOf(String)
347        // Integer.decode(String)
348        // Integer.getInteger(String)
349        // Integer.getInteger(String,int val)
350        // Integer.getInteger(String,Integer val)
351        // new Integer(String)
352        // new Double(String)
353        // new Byte(String)
354        // new Long(String)
355        // Long.getLong(String)
356        // Long.getLong(String,int)
357        // Long.getLong(String,Integer)
358        // Long.valueOf(String,int)
359        // Long.valueOf(String)
360        // new Short(String)
361        // Short.decode(String)
362        // Short.valueOf(String,int)
363        // Short.valueOf(String)
364        // new BigDecimal(String)
365        // new BigInteger(String)
366        // new BigInteger(String,int radix)
367        // Possible inputs:
368        // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
369        // plus minus everything. Prolly more. A lot are not separable.
370    
371        /**
372         * <p>Turns a string value into a java.lang.Number.</p>
373         *
374         * <p>First, the value is examined for a type qualifier on the end
375         * (<code>'f','F','d','D','l','L'</code>).  If it is found, it starts 
376         * trying to create successively larger types from the type specified
377         * until one is found that can represent the value.</p>
378         *
379         * <p>If a type specifier is not found, it will check for a decimal point
380         * and then try successively larger types from <code>Integer</code> to
381         * <code>BigInteger</code> and from <code>Float</code> to
382         * <code>BigDecimal</code>.</p>
383         *
384         * <p>If the string starts with <code>0x</code> or <code>-0x</code>, it
385         * will be interpreted as a hexadecimal integer.  Values with leading
386         * <code>0</code>'s will not be interpreted as octal.</p>
387         *
388         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
389         *
390         * <p>This method does not trim the input string, i.e., strings with leading
391         * or trailing spaces will generate NumberFormatExceptions.</p>
392         *
393         * @param str  String containing a number, may be null
394         * @return Number created from the string
395         * @throws NumberFormatException if the value cannot be converted
396         */
397        public static Number createNumber(String str) throws NumberFormatException {
398            if (str == null) {
399                return null;
400            }
401            if (StringUtils.isBlank(str)) {
402                throw new NumberFormatException("A blank string is not a valid number");
403            }  
404            if (str.startsWith("--")) {
405                // this is protection for poorness in java.lang.BigDecimal.
406                // it accepts this as a legal value, but it does not appear 
407                // to be in specification of class. OS X Java parses it to 
408                // a wrong value.
409                return null;
410            }
411            if (str.startsWith("0x") || str.startsWith("-0x")) {
412                return createInteger(str);
413            }   
414            char lastChar = str.charAt(str.length() - 1);
415            String mant;
416            String dec;
417            String exp;
418            int decPos = str.indexOf('.');
419            int expPos = str.indexOf('e') + str.indexOf('E') + 1;
420    
421            if (decPos > -1) {
422    
423                if (expPos > -1) {
424                    if (expPos < decPos) {
425                        throw new NumberFormatException(str + " is not a valid number.");
426                    }
427                    dec = str.substring(decPos + 1, expPos);
428                } else {
429                    dec = str.substring(decPos + 1);
430                }
431                mant = str.substring(0, decPos);
432            } else {
433                if (expPos > -1) {
434                    mant = str.substring(0, expPos);
435                } else {
436                    mant = str;
437                }
438                dec = null;
439            }
440            if (!Character.isDigit(lastChar)) {
441                if (expPos > -1 && expPos < str.length() - 1) {
442                    exp = str.substring(expPos + 1, str.length() - 1);
443                } else {
444                    exp = null;
445                }
446                //Requesting a specific type..
447                String numeric = str.substring(0, str.length() - 1);
448                boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
449                switch (lastChar) {
450                    case 'l' :
451                    case 'L' :
452                        if (dec == null
453                            && exp == null
454                            && (numeric.charAt(0) == '-' && isDigits(numeric.substring(1)) || isDigits(numeric))) {
455                            try {
456                                return createLong(numeric);
457                            } catch (NumberFormatException nfe) {
458                                //Too big for a long
459                            }
460                            return createBigInteger(numeric);
461    
462                        }
463                        throw new NumberFormatException(str + " is not a valid number.");
464                    case 'f' :
465                    case 'F' :
466                        try {
467                            Float f = NumberUtils.createFloat(numeric);
468                            if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
469                                //If it's too big for a float or the float value = 0 and the string
470                                //has non-zeros in it, then float does not have the precision we want
471                                return f;
472                            }
473    
474                        } catch (NumberFormatException nfe) {
475                            // ignore the bad number
476                        }
477                        //Fall through
478                    case 'd' :
479                    case 'D' :
480                        try {
481                            Double d = NumberUtils.createDouble(numeric);
482                            if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) {
483                                return d;
484                            }
485                        } catch (NumberFormatException nfe) {
486                            // ignore the bad number
487                        }
488                        try {
489                            return createBigDecimal(numeric);
490                        } catch (NumberFormatException e) {
491                            // ignore the bad number
492                        }
493                        //Fall through
494                    default :
495                        throw new NumberFormatException(str + " is not a valid number.");
496    
497                }
498            } else {
499                //User doesn't have a preference on the return type, so let's start
500                //small and go from there...
501                if (expPos > -1 && expPos < str.length() - 1) {
502                    exp = str.substring(expPos + 1, str.length());
503                } else {
504                    exp = null;
505                }
506                if (dec == null && exp == null) {
507                    //Must be an int,long,bigint
508                    try {
509                        return createInteger(str);
510                    } catch (NumberFormatException nfe) {
511                        // ignore the bad number
512                    }
513                    try {
514                        return createLong(str);
515                    } catch (NumberFormatException nfe) {
516                        // ignore the bad number
517                    }
518                    return createBigInteger(str);
519    
520                } else {
521                    //Must be a float,double,BigDec
522                    boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
523                    try {
524                        Float f = createFloat(str);
525                        if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
526                            return f;
527                        }
528                    } catch (NumberFormatException nfe) {
529                        // ignore the bad number
530                    }
531                    try {
532                        Double d = createDouble(str);
533                        if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) {
534                            return d;
535                        }
536                    } catch (NumberFormatException nfe) {
537                        // ignore the bad number
538                    }
539    
540                    return createBigDecimal(str);
541    
542                }
543            }
544        }
545    
546        /**
547         * <p>Utility method for {@link #createNumber(java.lang.String)}.</p>
548         *
549         * <p>Returns <code>true</code> if s is <code>null</code>.</p>
550         * 
551         * @param str  the String to check
552         * @return if it is all zeros or <code>null</code>
553         */
554        private static boolean isAllZeros(String str) {
555            if (str == null) {
556                return true;
557            }
558            for (int i = str.length() - 1; i >= 0; i--) {
559                if (str.charAt(i) != '0') {
560                    return false;
561                }
562            }
563            return str.length() > 0;
564        }
565    
566        //-----------------------------------------------------------------------
567        /**
568         * <p>Convert a <code>String</code> to a <code>Float</code>.</p>
569         *
570         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
571         * 
572         * @param str  a <code>String</code> to convert, may be null
573         * @return converted <code>Float</code>
574         * @throws NumberFormatException if the value cannot be converted
575         */
576        public static Float createFloat(String str) {
577            if (str == null) {
578                return null;
579            }
580            return Float.valueOf(str);
581        }
582    
583        /**
584         * <p>Convert a <code>String</code> to a <code>Double</code>.</p>
585         * 
586         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
587         *
588         * @param str  a <code>String</code> to convert, may be null
589         * @return converted <code>Double</code>
590         * @throws NumberFormatException if the value cannot be converted
591         */
592        public static Double createDouble(String str) {
593            if (str == null) {
594                return null;
595            }
596            return Double.valueOf(str);
597        }
598    
599        /**
600         * <p>Convert a <code>String</code> to a <code>Integer</code>, handling
601         * hex and octal notations.</p>
602         *
603         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
604         * 
605         * @param str  a <code>String</code> to convert, may be null
606         * @return converted <code>Integer</code>
607         * @throws NumberFormatException if the value cannot be converted
608         */
609        public static Integer createInteger(String str) {
610            if (str == null) {
611                return null;
612            }
613            // decode() handles 0xAABD and 0777 (hex and octal) as well.
614            return Integer.decode(str);
615        }
616    
617        /**
618         * <p>Convert a <code>String</code> to a <code>Long</code>.</p>
619         * 
620         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
621         *
622         * @param str  a <code>String</code> to convert, may be null
623         * @return converted <code>Long</code>
624         * @throws NumberFormatException if the value cannot be converted
625         */
626        public static Long createLong(String str) {
627            if (str == null) {
628                return null;
629            }
630            return Long.valueOf(str);
631        }
632    
633        /**
634         * <p>Convert a <code>String</code> to a <code>BigInteger</code>.</p>
635         *
636         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
637         * 
638         * @param str  a <code>String</code> to convert, may be null
639         * @return converted <code>BigInteger</code>
640         * @throws NumberFormatException if the value cannot be converted
641         */
642        public static BigInteger createBigInteger(String str) {
643            if (str == null) {
644                return null;
645            }
646            return new BigInteger(str);
647        }
648    
649        /**
650         * <p>Convert a <code>String</code> to a <code>BigDecimal</code>.</p>
651         * 
652         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
653         *
654         * @param str  a <code>String</code> to convert, may be null
655         * @return converted <code>BigDecimal</code>
656         * @throws NumberFormatException if the value cannot be converted
657         */
658        public static BigDecimal createBigDecimal(String str) {
659            if (str == null) {
660                return null;
661            }
662            // handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
663            if (StringUtils.isBlank(str)) {
664                throw new NumberFormatException("A blank string is not a valid number");
665            }  
666            return new BigDecimal(str);
667        }
668    
669        // Min in array
670        //--------------------------------------------------------------------
671        /**
672         * <p>Returns the minimum value in an array.</p>
673         * 
674         * @param array  an array, must not be null or empty
675         * @return the minimum value in the array
676         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
677         * @throws IllegalArgumentException if <code>array</code> is empty
678         */
679        public static long min(long[] array) {
680            // Validates input
681            if (array == null) {
682                throw new IllegalArgumentException("The Array must not be null");
683            } else if (array.length == 0) {
684                throw new IllegalArgumentException("Array cannot be empty.");
685            }
686        
687            // Finds and returns min
688            long min = array[0];
689            for (int i = 1; i < array.length; i++) {
690                if (array[i] < min) {
691                    min = array[i];
692                }
693            }
694        
695            return min;
696        }
697    
698        /**
699         * <p>Returns the minimum value in an array.</p>
700         * 
701         * @param array  an array, must not be null or empty
702         * @return the minimum value in the array
703         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
704         * @throws IllegalArgumentException if <code>array</code> is empty
705         */
706        public static int min(int[] array) {
707            // Validates input
708            if (array == null) {
709                throw new IllegalArgumentException("The Array must not be null");
710            } else if (array.length == 0) {
711                throw new IllegalArgumentException("Array cannot be empty.");
712            }
713        
714            // Finds and returns min
715            int min = array[0];
716            for (int j = 1; j < array.length; j++) {
717                if (array[j] < min) {
718                    min = array[j];
719                }
720            }
721        
722            return min;
723        }
724    
725        /**
726         * <p>Returns the minimum value in an array.</p>
727         * 
728         * @param array  an array, must not be null or empty
729         * @return the minimum value in the array
730         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
731         * @throws IllegalArgumentException if <code>array</code> is empty
732         */
733        public static short min(short[] array) {
734            // Validates input
735            if (array == null) {
736                throw new IllegalArgumentException("The Array must not be null");
737            } else if (array.length == 0) {
738                throw new IllegalArgumentException("Array cannot be empty.");
739            }
740        
741            // Finds and returns min
742            short min = array[0];
743            for (int i = 1; i < array.length; i++) {
744                if (array[i] < min) {
745                    min = array[i];
746                }
747            }
748        
749            return min;
750        }
751    
752        /**
753         * <p>Returns the minimum value in an array.</p>
754         * 
755         * @param array  an array, must not be null or empty
756         * @return the minimum value in the array
757         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
758         * @throws IllegalArgumentException if <code>array</code> is empty
759         */
760        public static byte min(byte[] array) {
761            // Validates input
762            if (array == null) {
763                throw new IllegalArgumentException("The Array must not be null");
764            } else if (array.length == 0) {
765                throw new IllegalArgumentException("Array cannot be empty.");
766            }
767        
768            // Finds and returns min
769            byte min = array[0];
770            for (int i = 1; i < array.length; i++) {
771                if (array[i] < min) {
772                    min = array[i];
773                }
774            }
775        
776            return min;
777        }
778    
779         /**
780         * <p>Returns the minimum value in an array.</p>
781         * 
782         * @param array  an array, must not be null or empty
783         * @return the minimum value in the array
784         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
785         * @throws IllegalArgumentException if <code>array</code> is empty
786         * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this method that handles NaN differently
787         */
788        public static double min(double[] array) {
789            // Validates input
790            if (array == null) {
791                throw new IllegalArgumentException("The Array must not be null");
792            } else if (array.length == 0) {
793                throw new IllegalArgumentException("Array cannot be empty.");
794            }
795        
796            // Finds and returns min
797            double min = array[0];
798            for (int i = 1; i < array.length; i++) {
799                if (Double.isNaN(array[i])) {
800                    return Double.NaN;
801                }
802                if (array[i] < min) {
803                    min = array[i];
804                }
805            }
806        
807            return min;
808        }
809    
810        /**
811         * <p>Returns the minimum value in an array.</p>
812         * 
813         * @param array  an array, must not be null or empty
814         * @return the minimum value in the array
815         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
816         * @throws IllegalArgumentException if <code>array</code> is empty
817         * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this method that handles NaN differently
818         */
819        public static float min(float[] array) {
820            // Validates input
821            if (array == null) {
822                throw new IllegalArgumentException("The Array must not be null");
823            } else if (array.length == 0) {
824                throw new IllegalArgumentException("Array cannot be empty.");
825            }
826        
827            // Finds and returns min
828            float min = array[0];
829            for (int i = 1; i < array.length; i++) {
830                if (Float.isNaN(array[i])) {
831                    return Float.NaN;
832                }
833                if (array[i] < min) {
834                    min = array[i];
835                }
836            }
837        
838            return min;
839        }
840    
841        // Max in array
842        //--------------------------------------------------------------------
843        /**
844         * <p>Returns the maximum value in an array.</p>
845         * 
846         * @param array  an array, must not be null or empty
847         * @return the minimum value in the array
848         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
849         * @throws IllegalArgumentException if <code>array</code> is empty
850         */
851        public static long max(long[] array) {
852            // Validates input
853            if (array == null) {
854                throw new IllegalArgumentException("The Array must not be null");
855            } else if (array.length == 0) {
856                throw new IllegalArgumentException("Array cannot be empty.");
857            }
858    
859            // Finds and returns max
860            long max = array[0];
861            for (int j = 1; j < array.length; j++) {
862                if (array[j] > max) {
863                    max = array[j];
864                }
865            }
866    
867            return max;
868        }
869    
870        /**
871         * <p>Returns the maximum value in an array.</p>
872         * 
873         * @param array  an array, must not be null or empty
874         * @return the minimum value in the array
875         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
876         * @throws IllegalArgumentException if <code>array</code> is empty
877         */
878        public static int max(int[] array) {
879            // Validates input
880            if (array == null) {
881                throw new IllegalArgumentException("The Array must not be null");
882            } else if (array.length == 0) {
883                throw new IllegalArgumentException("Array cannot be empty.");
884            }
885        
886            // Finds and returns max
887            int max = array[0];
888            for (int j = 1; j < array.length; j++) {
889                if (array[j] > max) {
890                    max = array[j];
891                }
892            }
893        
894            return max;
895        }
896    
897        /**
898         * <p>Returns the maximum value in an array.</p>
899         * 
900         * @param array  an array, must not be null or empty
901         * @return the minimum value in the array
902         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
903         * @throws IllegalArgumentException if <code>array</code> is empty
904         */
905        public static short max(short[] array) {
906            // Validates input
907            if (array == null) {
908                throw new IllegalArgumentException("The Array must not be null");
909            } else if (array.length == 0) {
910                throw new IllegalArgumentException("Array cannot be empty.");
911            }
912        
913            // Finds and returns max
914            short max = array[0];
915            for (int i = 1; i < array.length; i++) {
916                if (array[i] > max) {
917                    max = array[i];
918                }
919            }
920        
921            return max;
922        }
923    
924        /**
925         * <p>Returns the maximum value in an array.</p>
926         * 
927         * @param array  an array, must not be null or empty
928         * @return the minimum value in the array
929         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
930         * @throws IllegalArgumentException if <code>array</code> is empty
931         */
932        public static byte max(byte[] array) {
933            // Validates input
934            if (array == null) {
935                throw new IllegalArgumentException("The Array must not be null");
936            } else if (array.length == 0) {
937                throw new IllegalArgumentException("Array cannot be empty.");
938            }
939        
940            // Finds and returns max
941            byte max = array[0];
942            for (int i = 1; i < array.length; i++) {
943                if (array[i] > max) {
944                    max = array[i];
945                }
946            }
947        
948            return max;
949        }
950    
951        /**
952         * <p>Returns the maximum value in an array.</p>
953         * 
954         * @param array  an array, must not be null or empty
955         * @return the minimum value in the array
956         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
957         * @throws IllegalArgumentException if <code>array</code> is empty
958         * @see IEEE754rUtils#max(double[]) IEEE754rUtils for a version of this method that handles NaN differently
959         */
960        public static double max(double[] array) {
961            // Validates input
962            if (array== null) {
963                throw new IllegalArgumentException("The Array must not be null");
964            } else if (array.length == 0) {
965                throw new IllegalArgumentException("Array cannot be empty.");
966            }
967        
968            // Finds and returns max
969            double max = array[0];
970            for (int j = 1; j < array.length; j++) {
971                if (Double.isNaN(array[j])) {
972                    return Double.NaN;
973                }
974                if (array[j] > max) {
975                    max = array[j];
976                }
977            }
978        
979            return max;
980        }
981    
982        /**
983         * <p>Returns the maximum value in an array.</p>
984         * 
985         * @param array  an array, must not be null or empty
986         * @return the minimum value in the array
987         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
988         * @throws IllegalArgumentException if <code>array</code> is empty
989         * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this method that handles NaN differently
990         */
991        public static float max(float[] array) {
992            // Validates input
993            if (array == null) {
994                throw new IllegalArgumentException("The Array must not be null");
995            } else if (array.length == 0) {
996                throw new IllegalArgumentException("Array cannot be empty.");
997            }
998    
999            // Finds and returns max
1000            float max = array[0];
1001            for (int j = 1; j < array.length; j++) {
1002                if (Float.isNaN(array[j])) {
1003                    return Float.NaN;
1004                }
1005                if (array[j] > max) {
1006                    max = array[j];
1007                }
1008            }
1009    
1010            return max;
1011        }
1012         
1013        // 3 param min
1014        //-----------------------------------------------------------------------
1015        /**
1016         * <p>Gets the minimum of three <code>long</code> values.</p>
1017         * 
1018         * @param a  value 1
1019         * @param b  value 2
1020         * @param c  value 3
1021         * @return  the smallest of the values
1022         */
1023        public static long min(long a, long b, long c) {
1024            if (b < a) {
1025                a = b;
1026            }
1027            if (c < a) {
1028                a = c;
1029            }
1030            return a;
1031        }
1032    
1033        /**
1034         * <p>Gets the minimum of three <code>int</code> values.</p>
1035         * 
1036         * @param a  value 1
1037         * @param b  value 2
1038         * @param c  value 3
1039         * @return  the smallest of the values
1040         */
1041        public static int min(int a, int b, int c) {
1042            if (b < a) {
1043                a = b;
1044            }
1045            if (c < a) {
1046                a = c;
1047            }
1048            return a;
1049        }
1050    
1051        /**
1052         * <p>Gets the minimum of three <code>short</code> values.</p>
1053         * 
1054         * @param a  value 1
1055         * @param b  value 2
1056         * @param c  value 3
1057         * @return  the smallest of the values
1058         */
1059        public static short min(short a, short b, short c) {
1060            if (b < a) {
1061                a = b;
1062            }
1063            if (c < a) {
1064                a = c;
1065            }
1066            return a;
1067        }
1068    
1069        /**
1070         * <p>Gets the minimum of three <code>byte</code> values.</p>
1071         * 
1072         * @param a  value 1
1073         * @param b  value 2
1074         * @param c  value 3
1075         * @return  the smallest of the values
1076         */
1077        public static byte min(byte a, byte b, byte c) {
1078            if (b < a) {
1079                a = b;
1080            }
1081            if (c < a) {
1082                a = c;
1083            }
1084            return a;
1085        }
1086    
1087        /**
1088         * <p>Gets the minimum of three <code>double</code> values.</p>
1089         * 
1090         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1091         * returned. Infinity is handled.</p>
1092         * 
1093         * @param a  value 1
1094         * @param b  value 2
1095         * @param c  value 3
1096         * @return  the smallest of the values
1097         * @see IEEE754rUtils#min(double, double, double) for a version of this method that handles NaN differently
1098         */
1099        public static double min(double a, double b, double c) {
1100            return Math.min(Math.min(a, b), c);
1101        }
1102    
1103        /**
1104         * <p>Gets the minimum of three <code>float</code> values.</p>
1105         * 
1106         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1107         * returned. Infinity is handled.</p>
1108         *
1109         * @param a  value 1
1110         * @param b  value 2
1111         * @param c  value 3
1112         * @return  the smallest of the values
1113         * @see IEEE754rUtils#min(float, float, float) for a version of this method that handles NaN differently
1114         */
1115        public static float min(float a, float b, float c) {
1116            return Math.min(Math.min(a, b), c);
1117        }
1118    
1119        // 3 param max
1120        //-----------------------------------------------------------------------
1121        /**
1122         * <p>Gets the maximum of three <code>long</code> values.</p>
1123         * 
1124         * @param a  value 1
1125         * @param b  value 2
1126         * @param c  value 3
1127         * @return  the largest of the values
1128         */
1129        public static long max(long a, long b, long c) {
1130            if (b > a) {
1131                a = b;
1132            }
1133            if (c > a) {
1134                a = c;
1135            }
1136            return a;
1137        }
1138    
1139        /**
1140         * <p>Gets the maximum of three <code>int</code> values.</p>
1141         * 
1142         * @param a  value 1
1143         * @param b  value 2
1144         * @param c  value 3
1145         * @return  the largest of the values
1146         */
1147        public static int max(int a, int b, int c) {
1148            if (b > a) {
1149                a = b;
1150            }
1151            if (c > a) {
1152                a = c;
1153            }
1154            return a;
1155        }
1156    
1157        /**
1158         * <p>Gets the maximum of three <code>short</code> values.</p>
1159         * 
1160         * @param a  value 1
1161         * @param b  value 2
1162         * @param c  value 3
1163         * @return  the largest of the values
1164         */
1165        public static short max(short a, short b, short c) {
1166            if (b > a) {
1167                a = b;
1168            }
1169            if (c > a) {
1170                a = c;
1171            }
1172            return a;
1173        }
1174    
1175        /**
1176         * <p>Gets the maximum of three <code>byte</code> values.</p>
1177         * 
1178         * @param a  value 1
1179         * @param b  value 2
1180         * @param c  value 3
1181         * @return  the largest of the values
1182         */
1183        public static byte max(byte a, byte b, byte c) {
1184            if (b > a) {
1185                a = b;
1186            }
1187            if (c > a) {
1188                a = c;
1189            }
1190            return a;
1191        }
1192    
1193        /**
1194         * <p>Gets the maximum of three <code>double</code> values.</p>
1195         * 
1196         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1197         * returned. Infinity is handled.</p>
1198         *
1199         * @param a  value 1
1200         * @param b  value 2
1201         * @param c  value 3
1202         * @return  the largest of the values
1203         * @see IEEE754rUtils#max(double, double, double) for a version of this method that handles NaN differently
1204         */
1205        public static double max(double a, double b, double c) {
1206            return Math.max(Math.max(a, b), c);
1207        }
1208    
1209        /**
1210         * <p>Gets the maximum of three <code>float</code> values.</p>
1211         * 
1212         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
1213         * returned. Infinity is handled.</p>
1214         *
1215         * @param a  value 1
1216         * @param b  value 2
1217         * @param c  value 3
1218         * @return  the largest of the values
1219         * @see IEEE754rUtils#max(float, float, float) for a version of this method that handles NaN differently
1220         */
1221        public static float max(float a, float b, float c) {
1222            return Math.max(Math.max(a, b), c);
1223        }
1224    
1225        //-----------------------------------------------------------------------
1226        /**
1227         * <p>Compares two <code>doubles</code> for order.</p>
1228         *
1229         * <p>This method is more comprehensive than the standard Java greater
1230         * than, less than and equals operators.</p>
1231         * <ul>
1232         *  <li>It returns <code>-1</code> if the first value is less than the second.</li>
1233         *  <li>It returns <code>+1</code> if the first value is greater than the second.</li>
1234         *  <li>It returns <code>0</code> if the values are equal.</li>
1235         * </ul>
1236         *
1237         * <p>
1238         * The ordering is as follows, largest to smallest:
1239         * <ul>
1240         *  <li>NaN
1241         *  <li>Positive infinity
1242         *  <li>Maximum double
1243         *  <li>Normal positive numbers
1244         *  <li>+0.0
1245         *  <li>-0.0
1246         *  <li>Normal negative numbers
1247         *  <li>Minimum double (<code>-Double.MAX_VALUE</code>)
1248         *  <li>Negative infinity
1249         * </ul>
1250         * </p>
1251         *
1252         * <p>Comparing <code>NaN</code> with <code>NaN</code> will
1253         * return <code>0</code>.</p>
1254         * 
1255         * @param lhs  the first <code>double</code>
1256         * @param rhs  the second <code>double</code>
1257         * @return <code>-1</code> if lhs is less, <code>+1</code> if greater,
1258         *  <code>0</code> if equal to rhs
1259         */
1260        public static int compare(double lhs, double rhs) {
1261            if (lhs < rhs) {
1262                return -1;
1263            }
1264            if (lhs > rhs) {
1265                return +1;
1266            }
1267            // Need to compare bits to handle 0.0 == -0.0 being true
1268            // compare should put -0.0 < +0.0
1269            // Two NaNs are also == for compare purposes
1270            // where NaN == NaN is false
1271            long lhsBits = Double.doubleToLongBits(lhs);
1272            long rhsBits = Double.doubleToLongBits(rhs);
1273            if (lhsBits == rhsBits) {
1274                return 0;
1275            }
1276            // Something exotic! A comparison to NaN or 0.0 vs -0.0
1277            // Fortunately NaN's long is > than everything else
1278            // Also negzeros bits < poszero
1279            // NAN: 9221120237041090560
1280            // MAX: 9218868437227405311
1281            // NEGZERO: -9223372036854775808
1282            if (lhsBits < rhsBits) {
1283                return -1;
1284            } else {
1285                return +1;
1286            }
1287        }
1288        
1289        /**
1290         * <p>Compares two floats for order.</p>
1291         *
1292         * <p>This method is more comprehensive than the standard Java greater than,
1293         * less than and equals operators.</p>
1294         * <ul>
1295         *  <li>It returns <code>-1</code> if the first value is less than the second.
1296         *  <li>It returns <code>+1</code> if the first value is greater than the second.
1297         *  <li>It returns <code>0</code> if the values are equal.
1298         * </ul>
1299         *
1300         * <p> The ordering is as follows, largest to smallest:
1301         * <ul>
1302         * <li>NaN
1303         * <li>Positive infinity
1304         * <li>Maximum float
1305         * <li>Normal positive numbers
1306         * <li>+0.0
1307         * <li>-0.0
1308         * <li>Normal negative numbers
1309         * <li>Minimum float (<code>-Float.MAX_VALUE</code>)
1310         * <li>Negative infinity
1311         * </ul>
1312         *
1313         * <p>Comparing <code>NaN</code> with <code>NaN</code> will return
1314         * <code>0</code>.</p>
1315         * 
1316         * @param lhs  the first <code>float</code>
1317         * @param rhs  the second <code>float</code>
1318         * @return <code>-1</code> if lhs is less, <code>+1</code> if greater,
1319         *  <code>0</code> if equal to rhs
1320         */
1321        public static int compare(float lhs, float rhs) {
1322            if (lhs < rhs) {
1323                return -1;
1324            }
1325            if (lhs > rhs) {
1326                return +1;
1327            }
1328            //Need to compare bits to handle 0.0 == -0.0 being true
1329            // compare should put -0.0 < +0.0
1330            // Two NaNs are also == for compare purposes
1331            // where NaN == NaN is false
1332            int lhsBits = Float.floatToIntBits(lhs);
1333            int rhsBits = Float.floatToIntBits(rhs);
1334            if (lhsBits == rhsBits) {
1335                return 0;
1336            }
1337            //Something exotic! A comparison to NaN or 0.0 vs -0.0
1338            //Fortunately NaN's int is > than everything else
1339            //Also negzeros bits < poszero
1340            //NAN: 2143289344
1341            //MAX: 2139095039
1342            //NEGZERO: -2147483648
1343            if (lhsBits < rhsBits) {
1344                return -1;
1345            } else {
1346                return +1;
1347            }
1348        }
1349        
1350        //-----------------------------------------------------------------------
1351        /**
1352         * <p>Checks whether the <code>String</code> contains only
1353         * digit characters.</p>
1354         *
1355         * <p><code>Null</code> and empty String will return
1356         * <code>false</code>.</p>
1357         *
1358         * @param str  the <code>String</code> to check
1359         * @return <code>true</code> if str contains only unicode numeric
1360         */
1361        public static boolean isDigits(String str) {
1362            if (StringUtils.isEmpty(str)) {
1363                return false;
1364            }
1365            for (int i = 0; i < str.length(); i++) {
1366                if (!Character.isDigit(str.charAt(i))) {
1367                    return false;
1368                }
1369            }
1370            return true;
1371        }
1372    
1373        /**
1374         * <p>Checks whether the String a valid Java number.</p>
1375         *
1376         * <p>Valid numbers include hexadecimal marked with the <code>0x</code>
1377         * qualifier, scientific notation and numbers marked with a type
1378         * qualifier (e.g. 123L).</p>
1379         *
1380         * <p><code>Null</code> and empty String will return
1381         * <code>false</code>.</p>
1382         *
1383         * @param str  the <code>String</code> to check
1384         * @return <code>true</code> if the string is a correctly formatted number
1385         */
1386        public static boolean isNumber(String str) {
1387            if (StringUtils.isEmpty(str)) {
1388                return false;
1389            }
1390            char[] chars = str.toCharArray();
1391            int sz = chars.length;
1392            boolean hasExp = false;
1393            boolean hasDecPoint = false;
1394            boolean allowSigns = false;
1395            boolean foundDigit = false;
1396            // deal with any possible sign up front
1397            int start = (chars[0] == '-') ? 1 : 0;
1398            if (sz > start + 1) {
1399                if (chars[start] == '0' && chars[start + 1] == 'x') {
1400                    int i = start + 2;
1401                    if (i == sz) {
1402                        return false; // str == "0x"
1403                    }
1404                    // checking hex (it can't be anything else)
1405                    for (; i < chars.length; i++) {
1406                        if ((chars[i] < '0' || chars[i] > '9')
1407                            && (chars[i] < 'a' || chars[i] > 'f')
1408                            && (chars[i] < 'A' || chars[i] > 'F')) {
1409                            return false;
1410                        }
1411                    }
1412                    return true;
1413                }
1414            }
1415            sz--; // don't want to loop to the last char, check it afterwords
1416                  // for type qualifiers
1417            int i = start;
1418            // loop to the next to last char or to the last char if we need another digit to
1419            // make a valid number (e.g. chars[0..5] = "1234E")
1420            while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
1421                if (chars[i] >= '0' && chars[i] <= '9') {
1422                    foundDigit = true;
1423                    allowSigns = false;
1424    
1425                } else if (chars[i] == '.') {
1426                    if (hasDecPoint || hasExp) {
1427                        // two decimal points or dec in exponent   
1428                        return false;
1429                    }
1430                    hasDecPoint = true;
1431                } else if (chars[i] == 'e' || chars[i] == 'E') {
1432                    // we've already taken care of hex.
1433                    if (hasExp) {
1434                        // two E's
1435                        return false;
1436                    }
1437                    if (!foundDigit) {
1438                        return false;
1439                    }
1440                    hasExp = true;
1441                    allowSigns = true;
1442                } else if (chars[i] == '+' || chars[i] == '-') {
1443                    if (!allowSigns) {
1444                        return false;
1445                    }
1446                    allowSigns = false;
1447                    foundDigit = false; // we need a digit after the E
1448                } else {
1449                    return false;
1450                }
1451                i++;
1452            }
1453            if (i < chars.length) {
1454                if (chars[i] >= '0' && chars[i] <= '9') {
1455                    // no type qualifier, OK
1456                    return true;
1457                }
1458                if (chars[i] == 'e' || chars[i] == 'E') {
1459                    // can't have an E at the last byte
1460                    return false;
1461                }
1462                if (!allowSigns
1463                    && (chars[i] == 'd'
1464                        || chars[i] == 'D'
1465                        || chars[i] == 'f'
1466                        || chars[i] == 'F')) {
1467                    return foundDigit;
1468                }
1469                if (chars[i] == 'l'
1470                    || chars[i] == 'L') {
1471                    // not allowing L with an exponent
1472                    return foundDigit && !hasExp;
1473                }
1474                // last character is illegal
1475                return false;
1476            }
1477            // allowSigns is true iff the val ends in 'E'
1478            // found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
1479            return !allowSigns && foundDigit;
1480        }
1481        
1482    }