    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 Apache Software Foundation
    028     * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
    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 1056853 2011-01-09 01:07:04Z niallp $
    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.toInt("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         /**
    337         * <p>Convert a <code>String</code> to a <code>byte</code>, returning
    338         * <code>zero</code> if the conversion fails.</p>
    339         *
    340         * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
    341         *
    342         * <pre>
    343         *   NumberUtils.toByte(null) = 0
    344         *   NumberUtils.toByte("")   = 0
    345         *   NumberUtils.toByte("1")  = 1
    346         * </pre>
    347         *
    348         * @param str  the string to convert, may be null
    349         * @return the byte represented by the string, or <code>zero</code> if
    350         *  conversion fails
    351         * @since 2.5
    352         */
    353        public static byte toByte(String str) {
    354            return toByte(str, (byte) 0);
    355        }
    356
    357        /**
    358         * <p>Convert a <code>String</code> to a <code>byte</code>, returning a
    359         * default value if the conversion fails.</p>
    360         *
    361         * <p>If the string is <code>null</code>, the default value is returned.</p>
    362         *
    363         * <pre>
    364         *   NumberUtils.toByte(null, 1) = 1
    365         *   NumberUtils.toByte("", 1)   = 1
    366         *   NumberUtils.toByte("1", 0)  = 1
    367         * </pre>
    368         *
    369         * @param str  the string to convert, may be null
    370         * @param defaultValue  the default value
    371         * @return the byte represented by the string, or the default if conversion fails
    372         * @since 2.5
    373         */
    374        public static byte toByte(String str, byte defaultValue) {
    375            if(str == null) {
    376                return defaultValue;
    377            }
    378            try {
    379                return Byte.parseByte(str);
    380            } catch (NumberFormatException nfe) {
    381                return defaultValue;
    382            }
    383        }
    384
    385        /**
    386         * <p>Convert a <code>String</code> to a <code>short</code>, returning
    387         * <code>zero</code> if the conversion fails.</p>
    388         *
    389         * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
    390         *
    391         * <pre>
    392         *   NumberUtils.toShort(null) = 0
    393         *   NumberUtils.toShort("")   = 0
    394         *   NumberUtils.toShort("1")  = 1
    395         * </pre>
    396         *
    397         * @param str  the string to convert, may be null
    398         * @return the short represented by the string, or <code>zero</code> if
    399         *  conversion fails
    400         * @since 2.5
    401         */
    402        public static short toShort(String str) {
    403            return toShort(str, (short) 0);
    404        }
    405
    406        /**
    407         * <p>Convert a <code>String</code> to an <code>short</code>, returning a
    408         * default value if the conversion fails.</p>
    409         *
    410         * <p>If the string is <code>null</code>, the default value is returned.</p>
    411         *
    412         * <pre>
    413         *   NumberUtils.toShort(null, 1) = 1
    414         *   NumberUtils.toShort("", 1)   = 1
    415         *   NumberUtils.toShort("1", 0)  = 1
    416         * </pre>
    417         *
    418         * @param str  the string to convert, may be null
    419         * @param defaultValue  the default value
    420         * @return the short represented by the string, or the default if conversion fails
    421         * @since 2.5
    422         */
    423        public static short toShort(String str, short defaultValue) {
    424            if(str == null) {
    425                return defaultValue;
    426            }
    427            try {
    428                return Short.parseShort(str);
    429            } catch (NumberFormatException nfe) {
    430                return defaultValue;
    431            }
    432        }
    433
    434        //-----------------------------------------------------------------------
    435        // must handle Long, Float, Integer, Float, Short,
    436        //                  BigDecimal, BigInteger and Byte
    437        // useful methods:
    438        // Byte.decode(String)
    439        // Byte.valueOf(String,int radix)
    440        // Byte.valueOf(String)
    441        // Double.valueOf(String)
    442        // Float.valueOf(String)
    443        // new Float(String)
    444        // Integer.valueOf(String,int radix)
    445        // Integer.valueOf(String)
    446        // Integer.decode(String)
    447        // Integer.getInteger(String)
    448        // Integer.getInteger(String,int val)
    449        // Integer.getInteger(String,Integer val)
    450        // new Integer(String)
    451        // new Double(String)
    452        // new Byte(String)
    453        // new Long(String)
    454        // Long.getLong(String)
    455        // Long.getLong(String,int)
    456        // Long.getLong(String,Integer)
    457        // Long.valueOf(String,int)
    458        // Long.valueOf(String)
    459        // new Short(String)
    460        // Short.decode(String)
    461        // Short.valueOf(String,int)
    462        // Short.valueOf(String)
    463        // new BigDecimal(String)
    464        // new BigInteger(String)
    465        // new BigInteger(String,int radix)
    466        // Possible inputs:
    467        // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
    468        // plus minus everything. Prolly more. A lot are not separable.
    469
    470        /**
    471         * <p>Turns a string value into a java.lang.Number.</p>
    472         *
    473         * <p>First, the value is examined for a type qualifier on the end
    474         * (<code>'f','F','d','D','l','L'</code>).  If it is found, it starts
    475         * trying to create successively larger types from the type specified
    476         * until one is found that can represent the value.</p>
    477         *
    478         * <p>If a type specifier is not found, it will check for a decimal point
    479         * and then try successively larger types from <code>Integer</code> to
    480         * <code>BigInteger</code> and from <code>Float</code> to
    481         * <code>BigDecimal</code>.</p>
    482         *
    483         * <p>If the string starts with <code>0x</code> or <code>-0x</code>, it
    484         * will be interpreted as a hexadecimal integer.  Values with leading
    485         * <code>0</code>'s will not be interpreted as octal.</p>
    486         *
    487         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
    488         *
    489         * <p>This method does not trim the input string, i.e., strings with leading
    490         * or trailing spaces will generate NumberFormatExceptions.</p>
    491         *
    492         * @param str  String containing a number, may be null
    493         * @return Number created from the string
    494         * @throws NumberFormatException if the value cannot be converted
    495         */
    496        public static Number createNumber(String str) throws NumberFormatException {
    497            if (str == null) {
    498                return null;
    499            }
    500            if (StringUtils.isBlank(str)) {
    501                throw new NumberFormatException("A blank string is not a valid number");
    502            }
    503            if (str.startsWith("--")) {
    504                // this is protection for poorness in java.lang.BigDecimal.
    505                // it accepts this as a legal value, but it does not appear
    506                // to be in specification of class. OS X Java parses it to
    507                // a wrong value.
    508                return null;
    509            }
    510            if (str.startsWith("0x") || str.startsWith("-0x")) {
    511                return createInteger(str);
    512            }
    513            char lastChar = str.charAt(str.length() - 1);
    514            String mant;
    515            String dec;
    516            String exp;
    517            int decPos = str.indexOf('.');
    518            int expPos = str.indexOf('e') + str.indexOf('E') + 1;
    519
    520            if (decPos > -1) {
    521
    522                if (expPos > -1) {
    523                    if (expPos < decPos || expPos > str.length()) {
    524                        throw new NumberFormatException(str + " is not a valid number.");
    525                    }
    526                    dec = str.substring(decPos + 1, expPos);
    527                } else {
    528                    dec = str.substring(decPos + 1);
    529                }
    530                mant = str.substring(0, decPos);
    531            } else {
    532                if (expPos > -1) {
    533                    if (expPos > str.length()) {
    534                        throw new NumberFormatException(str + " is not a valid number.");
    535                    }
    536                    mant = str.substring(0, expPos);
    537                } else {
    538                    mant = str;
    539                }
    540                dec = null;
    541            }
    542            if (!Character.isDigit(lastChar) && lastChar != '.') {
    543                if (expPos > -1 && expPos < str.length() - 1) {
    544                    exp = str.substring(expPos + 1, str.length() - 1);
    545                } else {
    546                    exp = null;
    547                }
    548                //Requesting a specific type..
    549                String numeric = str.substring(0, str.length() - 1);
    550                boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
    551                switch (lastChar) {
    552                    case 'l' :
    553                    case 'L' :
    554                        if (dec == null
    555                            && exp == null
    556                            && (numeric.charAt(0) == '-' && isDigits(numeric.substring(1)) || isDigits(numeric))) {
    557                            try {
    558                                return createLong(numeric);
    559                            } catch (NumberFormatException nfe) {
    560                                //Too big for a long
    561                            }
    562                            return createBigInteger(numeric);
    563
    564                        }
    565                        throw new NumberFormatException(str + " is not a valid number.");
    566                    case 'f' :
    567                    case 'F' :
    568                        try {
    569                            Float f = NumberUtils.createFloat(numeric);
    570                            if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
    571                                //If it's too big for a float or the float value = 0 and the string
    572                                //has non-zeros in it, then float does not have the precision we want
    573                                return f;
    574                            }
    575
    576                        } catch (NumberFormatException nfe) {
    577                            // ignore the bad number
    578                        }
    579                        //$FALL-THROUGH$
    580                    case 'd' :
    581                    case 'D' :
    582                        try {
    583                            Double d = NumberUtils.createDouble(numeric);
    584                            if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) {
    585                                return d;
    586                            }
    587                        } catch (NumberFormatException nfe) {
    588                            // ignore the bad number
    589                        }
    590                        try {
    591                            return createBigDecimal(numeric);
    592                        } catch (NumberFormatException e) {
    593                            // ignore the bad number
    594                        }
    595                        //$FALL-THROUGH$
    596                    default :
    597                        throw new NumberFormatException(str + " is not a valid number.");
    598
    599                }
    600            } else {
    601                //User doesn't have a preference on the return type, so let's start
    602                //small and go from there...
    603                if (expPos > -1 && expPos < str.length() - 1) {
    604                    exp = str.substring(expPos + 1, str.length());
    605                } else {
    606                    exp = null;
    607                }
    608                if (dec == null && exp == null) {
    609                    //Must be an int,long,bigint
    610                    try {
    611                        return createInteger(str);
    612                    } catch (NumberFormatException nfe) {
    613                        // ignore the bad number
    614                    }
    615                    try {
    616                        return createLong(str);
    617                    } catch (NumberFormatException nfe) {
    618                        // ignore the bad number
    619                    }
    620                    return createBigInteger(str);
    621
    622                } else {
    623                    //Must be a float,double,BigDec
    624                    boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
    625                    try {
    626                        Float f = createFloat(str);
    627                        if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
    628                            return f;
    629                        }
    630                    } catch (NumberFormatException nfe) {
    631                        // ignore the bad number
    632                    }
    633                    try {
    634                        Double d = createDouble(str);
    635                        if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) {
    636                            return d;
    637                        }
    638                    } catch (NumberFormatException nfe) {
    639                        // ignore the bad number
    640                    }
    641
    642                    return createBigDecimal(str);
    643
    644                }
    645            }
    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(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>
    676         * @throws NumberFormatException if the value cannot be converted
    677         */
    678        public static Float createFloat(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>
    692         * @throws NumberFormatException if the value cannot be converted
    693         */
    694        public static Double createDouble(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 and octal notations.</p>
    704         *
    705         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
    706         *
    707         * @param str  a <code>String</code> to convert, may be null
    708         * @return converted <code>Integer</code>
    709         * @throws NumberFormatException if the value cannot be converted
    710         */
    711        public static Integer createInteger(String str) {
    712            if (str == null) {
    713                return null;
    714            }
    715            // decode() handles 0xAABD and 0777 (hex and octal) as well.
    716            return Integer.decode(str);
    717        }
    718
    719        /**
    720         * <p>Convert a <code>String</code> to a <code>Long</code>.</p>
    721         *
    722         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
    723         *
    724         * @param str  a <code>String</code> to convert, may be null
    725         * @return converted <code>Long</code>
    726         * @throws NumberFormatException if the value cannot be converted
    727         */
    728        public static Long createLong(String str) {
    729            if (str == null) {
    730                return null;
    731            }
    732            return Long.valueOf(str);
    733        }
    734
    735        /**
    736         * <p>Convert a <code>String</code> to a <code>BigInteger</code>.</p>
    737         *
    738         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
    739         *
    740         * @param str  a <code>String</code> to convert, may be null
    741         * @return converted <code>BigInteger</code>
    742         * @throws NumberFormatException if the value cannot be converted
    743         */
    744        public static BigInteger createBigInteger(String str) {
    745            if (str == null) {
    746                return null;
    747            }
    748            return new BigInteger(str);
    749        }
    750
    751        /**
    752         * <p>Convert a <code>String</code> to a <code>BigDecimal</code>.</p>
    753         *
    754         * <p>Returns <code>null</code> if the string is <code>null</code>.</p>
    755         *
    756         * @param str  a <code>String</code> to convert, may be null
    757         * @return converted <code>BigDecimal</code>
    758         * @throws NumberFormatException if the value cannot be converted
    759         */
    760        public static BigDecimal createBigDecimal(String str) {
    761            if (str == null) {
    762                return null;
    763            }
    764            // handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
    765            if (StringUtils.isBlank(str)) {
    766                throw new NumberFormatException("A blank string is not a valid number");
    767            }
    768            return new BigDecimal(str);
    769        }
    770
    771        // Min in array
    772        //--------------------------------------------------------------------
    773        /**
    774         * <p>Returns the minimum value in an array.</p>
    775         *
    776         * @param array  an array, must not be null or empty
    777         * @return the minimum value in the array
    778         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    779         * @throws IllegalArgumentException if <code>array</code> is empty
    780         */
    781        public static long min(long[] array) {
    782            // Validates input
    783            if (array == null) {
    784                throw new IllegalArgumentException("The Array must not be null");
    785            } else if (array.length == 0) {
    786                throw new IllegalArgumentException("Array cannot be empty.");
    787            }
    788
    789            // Finds and returns min
    790            long min = array[0];
    791            for (int i = 1; i < array.length; i++) {
    792                if (array[i] < min) {
    793                    min = array[i];
    794                }
    795            }
    796
    797            return min;
    798        }
    799
    800        /**
    801         * <p>Returns the minimum value in an array.</p>
    802         *
    803         * @param array  an array, must not be null or empty
    804         * @return the minimum value in the array
    805         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    806         * @throws IllegalArgumentException if <code>array</code> is empty
    807         */
    808        public static int min(int[] array) {
    809            // Validates input
    810            if (array == null) {
    811                throw new IllegalArgumentException("The Array must not be null");
    812            } else if (array.length == 0) {
    813                throw new IllegalArgumentException("Array cannot be empty.");
    814            }
    815
    816            // Finds and returns min
    817            int min = array[0];
    818            for (int j = 1; j < array.length; j++) {
    819                if (array[j] < min) {
    820                    min = array[j];
    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         */
    835        public static short min(short[] array) {
    836            // Validates input
    837            if (array == null) {
    838                throw new IllegalArgumentException("The Array must not be null");
    839            } else if (array.length == 0) {
    840                throw new IllegalArgumentException("Array cannot be empty.");
    841            }
    842
    843            // Finds and returns min
    844            short min = array[0];
    845            for (int i = 1; i < array.length; i++) {
    846                if (array[i] < min) {
    847                    min = array[i];
    848                }
    849            }
    850
    851            return min;
    852        }
    853
    854        /**
    855         * <p>Returns the minimum value in an array.</p>
    856         *
    857         * @param array  an array, must not be null or empty
    858         * @return the minimum value in the array
    859         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    860         * @throws IllegalArgumentException if <code>array</code> is empty
    861         */
    862        public static byte min(byte[] array) {
    863            // Validates input
    864            if (array == null) {
    865                throw new IllegalArgumentException("The Array must not be null");
    866            } else if (array.length == 0) {
    867                throw new IllegalArgumentException("Array cannot be empty.");
    868            }
    869
    870            // Finds and returns min
    871            byte min = array[0];
    872            for (int i = 1; i < array.length; i++) {
    873                if (array[i] < min) {
    874                    min = array[i];
    875                }
    876            }
    877
    878            return min;
    879        }
    880
    881         /**
    882         * <p>Returns the minimum value in an array.</p>
    883         *
    884         * @param array  an array, must not be null or empty
    885         * @return the minimum value in the array
    886         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    887         * @throws IllegalArgumentException if <code>array</code> is empty
    888         * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this method that handles NaN differently
    889         */
    890        public static double min(double[] array) {
    891            // Validates input
    892            if (array == null) {
    893                throw new IllegalArgumentException("The Array must not be null");
    894            } else if (array.length == 0) {
    895                throw new IllegalArgumentException("Array cannot be empty.");
    896            }
    897
    898            // Finds and returns min
    899            double min = array[0];
    900            for (int i = 1; i < array.length; i++) {
    901                if (Double.isNaN(array[i])) {
    902                    return Double.NaN;
    903                }
    904                if (array[i] < min) {
    905                    min = array[i];
    906                }
    907            }
    908
    909            return min;
    910        }
    911
    912        /**
    913         * <p>Returns the minimum value in an array.</p>
    914         *
    915         * @param array  an array, must not be null or empty
    916         * @return the minimum value in the array
    917         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    918         * @throws IllegalArgumentException if <code>array</code> is empty
    919         * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this method that handles NaN differently
    920         */
    921        public static float min(float[] array) {
    922            // Validates input
    923            if (array == null) {
    924                throw new IllegalArgumentException("The Array must not be null");
    925            } else if (array.length == 0) {
    926                throw new IllegalArgumentException("Array cannot be empty.");
    927            }
    928
    929            // Finds and returns min
    930            float min = array[0];
    931            for (int i = 1; i < array.length; i++) {
    932                if (Float.isNaN(array[i])) {
    933                    return Float.NaN;
    934                }
    935                if (array[i] < min) {
    936                    min = array[i];
    937                }
    938            }
    939
    940            return min;
    941        }
    942
    943        // Max in array
    944        //--------------------------------------------------------------------
    945        /**
    946         * <p>Returns the maximum value in an array.</p>
    947         *
    948         * @param array  an array, must not be null or empty
    949         * @return the minimum value in the array
    950         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    951         * @throws IllegalArgumentException if <code>array</code> is empty
    952         */
    953        public static long max(long[] array) {
    954            // Validates input
    955            if (array == null) {
    956                throw new IllegalArgumentException("The Array must not be null");
    957            } else if (array.length == 0) {
    958                throw new IllegalArgumentException("Array cannot be empty.");
    959            }
    960
    961            // Finds and returns max
    962            long max = array[0];
    963            for (int j = 1; j < array.length; j++) {
    964                if (array[j] > max) {
    965                    max = array[j];
    966                }
    967            }
    968
    969            return max;
    970        }
    971
    972        /**
    973         * <p>Returns the maximum value in an array.</p>
    974         *
    975         * @param array  an array, must not be null or empty
    976         * @return the minimum value in the array
    977         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    978         * @throws IllegalArgumentException if <code>array</code> is empty
    979         */
    980        public static int max(int[] array) {
    981            // Validates input
    982            if (array == null) {
    983                throw new IllegalArgumentException("The Array must not be null");
    984            } else if (array.length == 0) {
    985                throw new IllegalArgumentException("Array cannot be empty.");
    986            }
    987
    988            // Finds and returns max
    989            int max = array[0];
    990            for (int j = 1; j < array.length; j++) {
    991                if (array[j] > max) {
    992                    max = array[j];
    993                }
    994            }
    995
    996            return max;
    997        }
    998
    999        /**
    1000         * <p>Returns the maximum value in an array.</p>
    1001         *
    1002         * @param array  an array, must not be null or empty
    1003         * @return the minimum value in the array
    1004         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    1005         * @throws IllegalArgumentException if <code>array</code> is empty
    1006         */
    1007        public static short max(short[] array) {
    1008            // Validates input
    1009            if (array == null) {
    1010                throw new IllegalArgumentException("The Array must not be null");
    1011            } else if (array.length == 0) {
    1012                throw new IllegalArgumentException("Array cannot be empty.");
    1013            }
    1014
    1015            // Finds and returns max
    1016            short max = array[0];
    1017            for (int i = 1; i < array.length; i++) {
    1018                if (array[i] > max) {
    1019                    max = array[i];
    1020                }
    1021            }
    1022
    1023            return max;
    1024        }
    1025
    1026        /**
    1027         * <p>Returns the maximum value in an array.</p>
    1028         *
    1029         * @param array  an array, must not be null or empty
    1030         * @return the minimum value in the array
    1031         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    1032         * @throws IllegalArgumentException if <code>array</code> is empty
    1033         */
    1034        public static byte max(byte[] array) {
    1035            // Validates input
    1036            if (array == null) {
    1037                throw new IllegalArgumentException("The Array must not be null");
    1038            } else if (array.length == 0) {
    1039                throw new IllegalArgumentException("Array cannot be empty.");
    1040            }
    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 minimum 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         */
    1062        public static double max(double[] array) {
    1063            // Validates input
    1064            if (array== null) {
    1065                throw new IllegalArgumentException("The Array must not be null");
    1066            } else if (array.length == 0) {
    1067                throw new IllegalArgumentException("Array cannot be empty.");
    1068            }
    1069
    1070            // Finds and returns max
    1071            double max = array[0];
    1072            for (int j = 1; j < array.length; j++) {
    1073                if (Double.isNaN(array[j])) {
    1074                    return Double.NaN;
    1075                }
    1076                if (array[j] > max) {
    1077                    max = array[j];
    1078                }
    1079            }
    1080
    1081            return max;
    1082        }
    1083
    1084        /**
    1085         * <p>Returns the maximum value in an array.</p>
    1086         *
    1087         * @param array  an array, must not be null or empty
    1088         * @return the minimum value in the array
    1089         * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
    1090         * @throws IllegalArgumentException if <code>array</code> is empty
    1091         * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this method that handles NaN differently
    1092         */
    1093        public static float max(float[] array) {
    1094            // Validates input
    1095            if (array == null) {
    1096                throw new IllegalArgumentException("The Array must not be null");
    1097            } else if (array.length == 0) {
    1098                throw new IllegalArgumentException("Array cannot be empty.");
    1099            }
    1100
    1101            // Finds and returns max
    1102            float max = array[0];
    1103            for (int j = 1; j < array.length; j++) {
    1104                if (Float.isNaN(array[j])) {
    1105                    return Float.NaN;
    1106                }
    1107                if (array[j] > max) {
    1108                    max = array[j];
    1109                }
    1110            }
    1111
    1112            return max;
    1113        }
    1114
    1115        // 3 param min
    1116        //-----------------------------------------------------------------------
    1117        /**
    1118         * <p>Gets the minimum of three <code>long</code> values.</p>
    1119         *
    1120         * @param a  value 1
    1121         * @param b  value 2
    1122         * @param c  value 3
    1123         * @return  the smallest of the values
    1124         */
    1125        public static long min(long a, long b, long c) {
    1126            if (b < a) {
    1127                a = b;
    1128            }
    1129            if (c < a) {
    1130                a = c;
    1131            }
    1132            return a;
    1133        }
    1134
    1135        /**
    1136         * <p>Gets the minimum of three <code>int</code> values.</p>
    1137         *
    1138         * @param a  value 1
    1139         * @param b  value 2
    1140         * @param c  value 3
    1141         * @return  the smallest of the values
    1142         */
    1143        public static int min(int a, int b, int c) {
    1144            if (b < a) {
    1145                a = b;
    1146            }
    1147            if (c < a) {
    1148                a = c;
    1149            }
    1150            return a;
    1151        }
    1152
    1153        /**
    1154         * <p>Gets the minimum of three <code>short</code> values.</p>
    1155         *
    1156         * @param a  value 1
    1157         * @param b  value 2
    1158         * @param c  value 3
    1159         * @return  the smallest of the values
    1160         */
    1161        public static short min(short a, short b, short c) {
    1162            if (b < a) {
    1163                a = b;
    1164            }
    1165            if (c < a) {
    1166                a = c;
    1167            }
    1168            return a;
    1169        }
    1170
    1171        /**
    1172         * <p>Gets the minimum of three <code>byte</code> values.</p>
    1173         *
    1174         * @param a  value 1
    1175         * @param b  value 2
    1176         * @param c  value 3
    1177         * @return  the smallest of the values
    1178         */
    1179        public static byte min(byte a, byte b, byte c) {
    1180            if (b < a) {
    1181                a = b;
    1182            }
    1183            if (c < a) {
    1184                a = c;
    1185            }
    1186            return a;
    1187        }
    1188
    1189        /**
    1190         * <p>Gets the minimum of three <code>double</code> values.</p>
    1191         *
    1192         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
    1193         * returned. Infinity is handled.</p>
    1194         *
    1195         * @param a  value 1
    1196         * @param b  value 2
    1197         * @param c  value 3
    1198         * @return  the smallest of the values
    1199         * @see IEEE754rUtils#min(double, double, double) for a version of this method that handles NaN differently
    1200         */
    1201        public static double min(double a, double b, double c) {
    1202            return Math.min(Math.min(a, b), c);
    1203        }
    1204
    1205        /**
    1206         * <p>Gets the minimum of three <code>float</code> values.</p>
    1207         *
    1208         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
    1209         * returned. Infinity is handled.</p>
    1210         *
    1211         * @param a  value 1
    1212         * @param b  value 2
    1213         * @param c  value 3
    1214         * @return  the smallest of the values
    1215         * @see IEEE754rUtils#min(float, float, float) for a version of this method that handles NaN differently
    1216         */
    1217        public static float min(float a, float b, float c) {
    1218            return Math.min(Math.min(a, b), c);
    1219        }
    1220
    1221        // 3 param max
    1222        //-----------------------------------------------------------------------
    1223        /**
    1224         * <p>Gets the maximum of three <code>long</code> values.</p>
    1225         *
    1226         * @param a  value 1
    1227         * @param b  value 2
    1228         * @param c  value 3
    1229         * @return  the largest of the values
    1230         */
    1231        public static long max(long a, long b, long c) {
    1232            if (b > a) {
    1233                a = b;
    1234            }
    1235            if (c > a) {
    1236                a = c;
    1237            }
    1238            return a;
    1239        }
    1240
    1241        /**
    1242         * <p>Gets the maximum of three <code>int</code> values.</p>
    1243         *
    1244         * @param a  value 1
    1245         * @param b  value 2
    1246         * @param c  value 3
    1247         * @return  the largest of the values
    1248         */
    1249        public static int max(int a, int b, int c) {
    1250            if (b > a) {
    1251                a = b;
    1252            }
    1253            if (c > a) {
    1254                a = c;
    1255            }
    1256            return a;
    1257        }
    1258
    1259        /**
    1260         * <p>Gets the maximum of three <code>short</code> values.</p>
    1261         *
    1262         * @param a  value 1
    1263         * @param b  value 2
    1264         * @param c  value 3
    1265         * @return  the largest of the values
    1266         */
    1267        public static short max(short a, short b, short c) {
    1268            if (b > a) {
    1269                a = b;
    1270            }
    1271            if (c > a) {
    1272                a = c;
    1273            }
    1274            return a;
    1275        }
    1276
    1277        /**
    1278         * <p>Gets the maximum of three <code>byte</code> values.</p>
    1279         *
    1280         * @param a  value 1
    1281         * @param b  value 2
    1282         * @param c  value 3
    1283         * @return  the largest of the values
    1284         */
    1285        public static byte max(byte a, byte b, byte c) {
    1286            if (b > a) {
    1287                a = b;
    1288            }
    1289            if (c > a) {
    1290                a = c;
    1291            }
    1292            return a;
    1293        }
    1294
    1295        /**
    1296         * <p>Gets the maximum of three <code>double</code> values.</p>
    1297         *
    1298         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
    1299         * returned. Infinity is handled.</p>
    1300         *
    1301         * @param a  value 1
    1302         * @param b  value 2
    1303         * @param c  value 3
    1304         * @return  the largest of the values
    1305         * @see IEEE754rUtils#max(double, double, double) for a version of this method that handles NaN differently
    1306         */
    1307        public static double max(double a, double b, double c) {
    1308            return Math.max(Math.max(a, b), c);
    1309        }
    1310
    1311        /**
    1312         * <p>Gets the maximum of three <code>float</code> values.</p>
    1313         *
    1314         * <p>If any value is <code>NaN</code>, <code>NaN</code> is
    1315         * returned. Infinity is handled.</p>
    1316         *
    1317         * @param a  value 1
    1318         * @param b  value 2
    1319         * @param c  value 3
    1320         * @return  the largest of the values
    1321         * @see IEEE754rUtils#max(float, float, float) for a version of this method that handles NaN differently
    1322         */
    1323        public static float max(float a, float b, float c) {
    1324            return Math.max(Math.max(a, b), c);
    1325        }
    1326
    1327        //-----------------------------------------------------------------------
    1328        /**
    1329         * <p>Compares two <code>doubles</code> for order.</p>
    1330         *
    1331         * <p>This method is more comprehensive than the standard Java greater
    1332         * than, less than and equals operators.</p>
    1333         * <ul>
    1334         *  <li>It returns <code>-1</code> if the first value is less than the second.</li>
    1335         *  <li>It returns <code>+1</code> if the first value is greater than the second.</li>
    1336         *  <li>It returns <code>0</code> if the values are equal.</li>
    1337         * </ul>
    1338         *
    1339         * <p>
    1340         * The ordering is as follows, largest to smallest:
    1341         * <ul>
    1342         *  <li>NaN
    1343         *  <li>Positive infinity
    1344         *  <li>Maximum double
    1345         *  <li>Normal positive numbers
    1346         *  <li>+0.0
    1347         *  <li>-0.0
    1348         *  <li>Normal negative numbers
    1349         *  <li>Minimum double (<code>-Double.MAX_VALUE</code>)
    1350         *  <li>Negative infinity
    1351         * </ul>
    1352         * </p>
    1353         *
    1354         * <p>Comparing <code>NaN</code> with <code>NaN</code> will
    1355         * return <code>0</code>.</p>
    1356         *
    1357         * @param lhs  the first <code>double</code>
    1358         * @param rhs  the second <code>double</code>
    1359         * @return <code>-1</code> if lhs is less, <code>+1</code> if greater,
    1360         *  <code>0</code> if equal to rhs
    1361         */
    1362        public static int compare(double lhs, double rhs) {
    1363            if (lhs < rhs) {
    1364                return -1;
    1365            }
    1366            if (lhs > rhs) {
    1367                return +1;
    1368            }
    1369            // Need to compare bits to handle 0.0 == -0.0 being true
    1370            // compare should put -0.0 < +0.0
    1371            // Two NaNs are also == for compare purposes
    1372            // where NaN == NaN is false
    1373            long lhsBits = Double.doubleToLongBits(lhs);
    1374            long rhsBits = Double.doubleToLongBits(rhs);
    1375            if (lhsBits == rhsBits) {
    1376                return 0;
    1377            }
    1378            // Something exotic! A comparison to NaN or 0.0 vs -0.0
    1379            // Fortunately NaN's long is > than everything else
    1380            // Also negzeros bits < poszero
    1381            // NAN: 9221120237041090560
    1382            // MAX: 9218868437227405311
    1383            // NEGZERO: -9223372036854775808
    1384            if (lhsBits < rhsBits) {
    1385                return -1;
    1386            } else {
    1387                return +1;
    1388            }
    1389        }
    1390
    1391        /**
    1392         * <p>Compares two floats for order.</p>
    1393         *
    1394         * <p>This method is more comprehensive than the standard Java greater than,
    1395         * less than and equals operators.</p>
    1396         * <ul>
    1397         *  <li>It returns <code>-1</code> if the first value is less than the second.
    1398         *  <li>It returns <code>+1</code> if the first value is greater than the second.
    1399         *  <li>It returns <code>0</code> if the values are equal.
    1400         * </ul>
    1401         *
    1402         * <p> The ordering is as follows, largest to smallest:
    1403         * <ul>
    1404         * <li>NaN
    1405         * <li>Positive infinity
    1406         * <li>Maximum float
    1407         * <li>Normal positive numbers
    1408         * <li>+0.0
    1409         * <li>-0.0
    1410         * <li>Normal negative numbers
    1411         * <li>Minimum float (<code>-Float.MAX_VALUE</code>)
    1412         * <li>Negative infinity
    1413         * </ul>
    1414         *
    1415         * <p>Comparing <code>NaN</code> with <code>NaN</code> will return
    1416         * <code>0</code>.</p>
    1417         *
    1418         * @param lhs  the first <code>float</code>
    1419         * @param rhs  the second <code>float</code>
    1420         * @return <code>-1</code> if lhs is less, <code>+1</code> if greater,
    1421         *  <code>0</code> if equal to rhs
    1422         */
    1423        public static int compare(float lhs, float rhs) {
    1424            if (lhs < rhs) {
    1425                return -1;
    1426            }
    1427            if (lhs > rhs) {
    1428                return +1;
    1429            }
    1430            //Need to compare bits to handle 0.0 == -0.0 being true
    1431            // compare should put -0.0 < +0.0
    1432            // Two NaNs are also == for compare purposes
    1433            // where NaN == NaN is false
    1434            int lhsBits = Float.floatToIntBits(lhs);
    1435            int rhsBits = Float.floatToIntBits(rhs);
    1436            if (lhsBits == rhsBits) {
    1437                return 0;
    1438            }
    1439            //Something exotic! A comparison to NaN or 0.0 vs -0.0
    1440            //Fortunately NaN's int is > than everything else
    1441            //Also negzeros bits < poszero
    1442            //NAN: 2143289344
    1443            //MAX: 2139095039
    1444            //NEGZERO: -2147483648
    1445            if (lhsBits < rhsBits) {
    1446                return -1;
    1447            } else {
    1448                return +1;
    1449            }
    1450        }
    1451
    1452        //-----------------------------------------------------------------------
    1453        /**
    1454         * <p>Checks whether the <code>String</code> contains only
    1455         * digit characters.</p>
    1456         *
    1457         * <p><code>Null</code> and empty String will return
    1458         * <code>false</code>.</p>
    1459         *
    1460         * @param str  the <code>String</code> to check
    1461         * @return <code>true</code> if str contains only unicode numeric
    1462         */
    1463        public static boolean isDigits(String str) {
    1464            if (StringUtils.isEmpty(str)) {
    1465                return false;
    1466            }
    1467            for (int i = 0; i < str.length(); i++) {
    1468                if (!Character.isDigit(str.charAt(i))) {
    1469                    return false;
    1470                }
    1471            }
    1472            return true;
    1473        }
    1474
    1475        /**
    1476         * <p>Checks whether the String a valid Java number.</p>
    1477         *
    1478         * <p>Valid numbers include hexadecimal marked with the <code>0x</code>
    1479         * qualifier, scientific notation and numbers marked with a type
    1480         * qualifier (e.g. 123L).</p>
    1481         *
    1482         * <p><code>Null</code> and empty String will return
    1483         * <code>false</code>.</p>
    1484         *
    1485         * @param str  the <code>String</code> to check
    1486         * @return <code>true</code> if the string is a correctly formatted number
    1487         */
    1488        public static boolean isNumber(String str) {
    1489            if (StringUtils.isEmpty(str)) {
    1490                return false;
    1491            }
    1492            char[] chars = str.toCharArray();
    1493            int sz = chars.length;
    1494            boolean hasExp = false;
    1495            boolean hasDecPoint = false;
    1496            boolean allowSigns = false;
    1497            boolean foundDigit = false;
    1498            // deal with any possible sign up front
    1499            int start = (chars[0] == '-') ? 1 : 0;
    1500            if (sz > start + 1) {
    1501                if (chars[start] == '0' && chars[start + 1] == 'x') {
    1502                    int i = start + 2;
    1503                    if (i == sz) {
    1504                        return false; // str == "0x"
    1505                    }
    1506                    // checking hex (it can't be anything else)
    1507                    for (; i < chars.length; i++) {
    1508                        if ((chars[i] < '0' || chars[i] > '9')
    1509                            && (chars[i] < 'a' || chars[i] > 'f')
    1510                            && (chars[i] < 'A' || chars[i] > 'F')) {
    1511                            return false;
    1512                        }
    1513                    }
    1514                    return true;
    1515                }
    1516            }
    1517            sz--; // don't want to loop to the last char, check it afterwords
    1518                  // for type qualifiers
    1519            int i = start;
    1520            // loop to the next to last char or to the last char if we need another digit to
    1521            // make a valid number (e.g. chars[0..5] = "1234E")
    1522            while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
    1523                if (chars[i] >= '0' && chars[i] <= '9') {
    1524                    foundDigit = true;
    1525                    allowSigns = false;
    1526
    1527                } else if (chars[i] == '.') {
    1528                    if (hasDecPoint || hasExp) {
    1529                        // two decimal points or dec in exponent
    1530                        return false;
    1531                    }
    1532                    hasDecPoint = true;
    1533                } else if (chars[i] == 'e' || chars[i] == 'E') {
    1534                    // we've already taken care of hex.
    1535                    if (hasExp) {
    1536                        // two E's
    1537                        return false;
    1538                    }
    1539                    if (!foundDigit) {
    1540                        return false;
    1541                    }
    1542                    hasExp = true;
    1543                    allowSigns = true;
    1544                } else if (chars[i] == '+' || chars[i] == '-') {
    1545                    if (!allowSigns) {
    1546                        return false;
    1547                    }
    1548                    allowSigns = false;
    1549                    foundDigit = false; // we need a digit after the E
    1550                } else {
    1551                    return false;
    1552                }
    1553                i++;
    1554            }
    1555            if (i < chars.length) {
    1556                if (chars[i] >= '0' && chars[i] <= '9') {
    1557                    // no type qualifier, OK
    1558                    return true;
    1559                }
    1560                if (chars[i] == 'e' || chars[i] == 'E') {
    1561                    // can't have an E at the last byte
    1562                    return false;
    1563                }
    1564                if (chars[i] == '.') {
    1565                    if (hasDecPoint || hasExp) {
    1566                        // two decimal points or dec in exponent
    1567                        return false;
    1568                    }
    1569                    // single trailing decimal point after non-exponent is ok
    1570                    return foundDigit;
    1571                }
    1572                if (!allowSigns
    1573                    && (chars[i] == 'd'
    1574                        || chars[i] == 'D'
    1575                        || chars[i] == 'f'
    1576                        || chars[i] == 'F')) {
    1577                    return foundDigit;
    1578                }
    1579                if (chars[i] == 'l'
    1580                    || chars[i] == 'L') {
    1581                    // not allowing L with an exponent
    1582                    return foundDigit && !hasExp;
    1583                }
    1584                // last character is illegal
    1585                return false;
    1586            }
    1587            // allowSigns is true iff the val ends in 'E'
    1588            // found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
    1589            return !allowSigns && foundDigit;
    1590        }
    1591
    1592    }