    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.math;
    018
    019import java.lang.reflect.Array;
    020import java.math.BigDecimal;
    021import java.math.BigInteger;
    022import java.math.RoundingMode;
    023import java.util.Objects;
    024
    025import org.apache.commons.lang3.StringUtils;
    026import org.apache.commons.lang3.Validate;
    027
    028/**
    029 * Provides extra functionality for Java Number classes.
    030 *
    031 * @since 2.0
    032 */
    033public class NumberUtils {
    034
    035    /** Reusable Long constant for zero. */
    036    public static final Long LONG_ZERO = Long.valueOf(0L);
    037    /** Reusable Long constant for one. */
    038    public static final Long LONG_ONE = Long.valueOf(1L);
    039    /** Reusable Long constant for minus one. */
    040    public static final Long LONG_MINUS_ONE = Long.valueOf(-1L);
    041    /** Reusable Integer constant for zero. */
    042    public static final Integer INTEGER_ZERO = Integer.valueOf(0);
    043    /** Reusable Integer constant for one. */
    044    public static final Integer INTEGER_ONE = Integer.valueOf(1);
    045    /** Reusable Integer constant for two */
    046    public static final Integer INTEGER_TWO = Integer.valueOf(2);
    047    /** Reusable Integer constant for minus one. */
    048    public static final Integer INTEGER_MINUS_ONE = Integer.valueOf(-1);
    049    /** Reusable Short constant for zero. */
    050    public static final Short SHORT_ZERO = Short.valueOf((short) 0);
    051    /** Reusable Short constant for one. */
    052    public static final Short SHORT_ONE = Short.valueOf((short) 1);
    053    /** Reusable Short constant for minus one. */
    054    public static final Short SHORT_MINUS_ONE = Short.valueOf((short) -1);
    055    /** Reusable Byte constant for zero. */
    056    public static final Byte BYTE_ZERO = Byte.valueOf((byte) 0);
    057    /** Reusable Byte constant for one. */
    058    public static final Byte BYTE_ONE = Byte.valueOf((byte) 1);
    059    /** Reusable Byte constant for minus one. */
    060    public static final Byte BYTE_MINUS_ONE = Byte.valueOf((byte) -1);
    061    /** Reusable Double constant for zero. */
    062    public static final Double DOUBLE_ZERO = Double.valueOf(0.0d);
    063    /** Reusable Double constant for one. */
    064    public static final Double DOUBLE_ONE = Double.valueOf(1.0d);
    065    /** Reusable Double constant for minus one. */
    066    public static final Double DOUBLE_MINUS_ONE = Double.valueOf(-1.0d);
    067    /** Reusable Float constant for zero. */
    068    public static final Float FLOAT_ZERO = Float.valueOf(0.0f);
    069    /** Reusable Float constant for one. */
    070    public static final Float FLOAT_ONE = Float.valueOf(1.0f);
    071    /** Reusable Float constant for minus one. */
    072    public static final Float FLOAT_MINUS_ONE = Float.valueOf(-1.0f);
    073
    074    /**
    075     * {@link Integer#MAX_VALUE} as a {@link Long}.
    076     *
    077     * @since 3.12.0
    078     */
    079    public static final Long LONG_INT_MAX_VALUE = Long.valueOf(Integer.MAX_VALUE);
    080
    081    /**
    082     * {@link Integer#MIN_VALUE} as a {@link Long}.
    083     *
    084     * @since 3.12.0
    085     */
    086    public static final Long LONG_INT_MIN_VALUE = Long.valueOf(Integer.MIN_VALUE);
    087
    088    /**
    089     * Compares two {@code byte} values numerically. This is the same functionality as provided in Java 7.
    090     *
    091     * @param x the first {@code byte} to compare
    092     * @param y the second {@code byte} to compare
    093     * @return the value {@code 0} if {@code x == y};
    094     *         a value less than {@code 0} if {@code x < y}; and
    095     *         a value greater than {@code 0} if {@code x > y}
    096     * @since 3.4
    097     */
    098    public static int compare(final byte x, final byte y) {
    099        return x - y;
    100    }
    101
    102    /**
    103     * Compares two {@code int} values numerically. This is the same functionality as provided in Java 7.
    104     *
    105     * @param x the first {@code int} to compare
    106     * @param y the second {@code int} to compare
    107     * @return the value {@code 0} if {@code x == y};
    108     *         a value less than {@code 0} if {@code x < y}; and
    109     *         a value greater than {@code 0} if {@code x > y}
    110     * @since 3.4
    111     */
    112    public static int compare(final int x, final int y) {
    113        if (x == y) {
    114            return 0;
    115        }
    116        return x < y ? -1 : 1;
    117    }
    118
    119    /**
    120     * Compares to {@code long} values numerically. This is the same functionality as provided in Java 7.
    121     *
    122     * @param x the first {@code long} to compare
    123     * @param y the second {@code long} to compare
    124     * @return the value {@code 0} if {@code x == y};
    125     *         a value less than {@code 0} if {@code x < y}; and
    126     *         a value greater than {@code 0} if {@code x > y}
    127     * @since 3.4
    128     */
    129    public static int compare(final long x, final long y) {
    130        if (x == y) {
    131            return 0;
    132        }
    133        return x < y ? -1 : 1;
    134    }
    135
    136    /**
    137     * Compares to {@code short} values numerically. This is the same functionality as provided in Java 7.
    138     *
    139     * @param x the first {@code short} to compare
    140     * @param y the second {@code short} to compare
    141     * @return the value {@code 0} if {@code x == y};
    142     *         a value less than {@code 0} if {@code x < y}; and
    143     *         a value greater than {@code 0} if {@code x > y}
    144     * @since 3.4
    145     */
    146    public static int compare(final short x, final short y) {
    147        if (x == y) {
    148            return 0;
    149        }
    150        return x < y ? -1 : 1;
    151    }
    152
    153    /**
    154     * Creates a {@link BigDecimal} from a {@link String}.
    155     *
    156     * <p>Returns {@code null} if the string is {@code null}.</p>
    157     *
    158     * @param str  a {@link String} to convert, may be null
    159     * @return converted {@link BigDecimal} (or null if the input is null)
    160     * @throws NumberFormatException if the value cannot be converted
    161     */
    162    public static BigDecimal createBigDecimal(final String str) {
    163        if (str == null) {
    164            return null;
    165        }
    166        // handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
    167        if (StringUtils.isBlank(str)) {
    168            throw new NumberFormatException("A blank string is not a valid number");
    169        }
    170        return new BigDecimal(str);
    171    }
    172
    173    /**
    174     * Creates a {@link BigInteger} from a {@link String}.
    175     *
    176     * Handles hexadecimal (0x or #) and octal (0) notations.
    177     *
    178     * <p>Returns {@code null} if the string is {@code null}.</p>
    179     *
    180     * @param str  a {@link String} to convert, may be null
    181     * @return converted {@link BigInteger} (or null if the input is null)
    182     * @throws NumberFormatException if the value cannot be converted
    183     * @since 3.2
    184     */
    185    public static BigInteger createBigInteger(final String str) {
    186        if (str == null) {
    187            return null;
    188        }
    189        if (str.isEmpty()) {
    190            throw new NumberFormatException("An empty string is not a valid number");
    191        }
    192        int pos = 0; // offset within string
    193        int radix = 10;
    194        boolean negate = false; // need to negate later?
    195        final char char0 = str.charAt(0);
    196        if (char0 == '-') {
    197            negate = true;
    198            pos = 1;
    199        } else if (char0 == '+') {
    200            pos = 1;
    201        }
    202        if (str.startsWith("0x", pos) || str.startsWith("0X", pos)) { // hex
    203            radix = 16;
    204            pos += 2;
    205        } else if (str.startsWith("#", pos)) { // alternative hex (allowed by Long/Integer)
    206            radix = 16;
    207            pos++;
    208        } else if (str.startsWith("0", pos) && str.length() > pos + 1) { // octal; so long as there are additional digits
    209            radix = 8;
    210            pos++;
    211        } // default is to treat as decimal
    212
    213        final BigInteger value = new BigInteger(str.substring(pos), radix);
    214        return negate ? value.negate() : value;
    215    }
    216
    217    /**
    218     * Creates a {@link Double} from a {@link String}.
    219     *
    220     * <p>Returns {@code null} if the string is {@code null}.</p>
    221     *
    222     * @param str  a {@link String} to convert, may be null
    223     * @return converted {@link Double} (or null if the input is null)
    224     * @throws NumberFormatException if the value cannot be converted
    225     */
    226    public static Double createDouble(final String str) {
    227        if (str == null) {
    228            return null;
    229        }
    230        return Double.valueOf(str);
    231    }
    232
    233    /**
    234     * Creates a {@link Float} from a {@link String}.
    235     *
    236     * <p>Returns {@code null} if the string is {@code null}.</p>
    237     *
    238     * @param str  a {@link String} to convert, may be null
    239     * @return converted {@link Float} (or null if the input is null)
    240     * @throws NumberFormatException if the value cannot be converted
    241     */
    242    public static Float createFloat(final String str) {
    243        if (str == null) {
    244            return null;
    245        }
    246        return Float.valueOf(str);
    247    }
    248
    249    /**
    250     * Creates an {@link Integer} from a {@link String}.
    251     *
    252     * Handles hexadecimal (0xhhhh) and octal (0dddd) notations.
    253     * N.B. a leading zero means octal; spaces are not trimmed.
    254     *
    255     * <p>Returns {@code null} if the string is {@code null}.</p>
    256     *
    257     * @param str  a {@link String} to convert, may be null
    258     * @return converted {@link Integer} (or null if the input is null)
    259     * @throws NumberFormatException if the value cannot be converted
    260     */
    261    public static Integer createInteger(final String str) {
    262        if (str == null) {
    263            return null;
    264        }
    265        // decode() handles 0xAABD and 0777 (hex and octal) as well.
    266        return Integer.decode(str);
    267    }
    268
    269    /**
    270     * Creates a {@link Long} from a {@link String}.
    271     *
    272     * Handles hexadecimal (0Xhhhh) and octal (0ddd) notations.
    273     * N.B. a leading zero means octal; spaces are not trimmed.
    274     *
    275     * <p>Returns {@code null} if the string is {@code null}.</p>
    276     *
    277     * @param str  a {@link String} to convert, may be null
    278     * @return converted {@link Long} (or null if the input is null)
    279     * @throws NumberFormatException if the value cannot be converted
    280     * @since 3.1
    281     */
    282    public static Long createLong(final String str) {
    283        if (str == null) {
    284            return null;
    285        }
    286        return Long.decode(str);
    287    }
    288
    289    /**
    290     * Creates a {@link Number} from a {@link String}.
    291     *
    292     * <p>If the string starts with {@code 0x} or {@code -0x} (lower or upper case) or {@code #} or {@code -#}, it
    293     * will be interpreted as a hexadecimal Integer - or Long, if the number of digits after the
    294     * prefix is more than 8 - or BigInteger if there are more than 16 digits.
    295     * </p>
    296     * <p>Then, the value is examined for a type qualifier on the end, i.e. one of
    297     * {@code 'f', 'F', 'd', 'D', 'l', 'L'}.  If it is found, it starts
    298     * trying to create successively larger types from the type specified
    299     * until one is found that can represent the value.</p>
    300     *
    301     * <p>If a type specifier is not found, it will check for a decimal point
    302     * and then try successively larger types from {@link Integer} to
    303     * {@link BigInteger} and from {@link Float} to
    304     * {@link BigDecimal}.</p>
    305     *
    306     * <p>
    307     * Integral values with a leading {@code 0} will be interpreted as octal; the returned number will
    308     * be Integer, Long or BigDecimal as appropriate.
    309     * </p>
    310     *
    311     * <p>Returns {@code null} if the string is {@code null}.</p>
    312     *
    313     * <p>This method does not trim the input string, i.e., strings with leading
    314     * or trailing spaces will generate NumberFormatExceptions.</p>
    315     *
    316     * @param str  String containing a number, may be null
    317     * @return Number created from the string (or null if the input is null)
    318     * @throws NumberFormatException if the value cannot be converted
    319     */
    320    public static Number createNumber(final String str) {
    321        if (str == null) {
    322            return null;
    323        }
    324        if (StringUtils.isBlank(str)) {
    325            throw new NumberFormatException("A blank string is not a valid number");
    326        }
    327        // Need to deal with all possible hex prefixes here
    328        final String[] hexPrefixes = {"0x", "0X", "#"};
    329        final int length = str.length();
    330        final int offset = str.charAt(0) == '+' || str.charAt(0) == '-' ? 1 : 0;
    331        int pfxLen = 0;
    332        for (final String pfx : hexPrefixes) {
    333            if (str.startsWith(pfx, offset)) {
    334                pfxLen += pfx.length() + offset;
    335                break;
    336            }
    337        }
    338        if (pfxLen > 0) { // we have a hex number
    339            char firstSigDigit = 0; // strip leading zeroes
    340            for (int i = pfxLen; i < length; i++) {
    341                firstSigDigit = str.charAt(i);
    342                if (firstSigDigit != '0') {
    343                    break;
    344                }
    345                pfxLen++;
    346            }
    347            final int hexDigits = length - pfxLen;
    348            if (hexDigits > 16 || hexDigits == 16 && firstSigDigit > '7') { // too many for Long
    349                return createBigInteger(str);
    350            }
    351            if (hexDigits > 8 || hexDigits == 8 && firstSigDigit > '7') { // too many for an int
    352                return createLong(str);
    353            }
    354            return createInteger(str);
    355        }
    356        final char lastChar = str.charAt(length - 1);
    357        final String mant;
    358        final String dec;
    359        final String exp;
    360        final int decPos = str.indexOf('.');
    361        final int expPos = str.indexOf('e') + str.indexOf('E') + 1; // assumes both not present
    362        // if both e and E are present, this is caught by the checks on expPos (which prevent IOOBE)
    363        // and the parsing which will detect if e or E appear in a number due to using the wrong offset
    364
    365        // Detect if the return type has been requested
    366        final boolean requestType = !Character.isDigit(lastChar) && lastChar != '.';
    367        if (decPos > -1) { // there is a decimal point
    368            if (expPos > -1) { // there is an exponent
    369                if (expPos <= decPos || expPos > length) { // prevents double exponent causing IOOBE
    370                    throw new NumberFormatException(str + " is not a valid number.");
    371                }
    372                dec = str.substring(decPos + 1, expPos);
    373            } else {
    374                // No exponent, but there may be a type character to remove
    375                dec = str.substring(decPos + 1, requestType ? length - 1 : length);
    376            }
    377            mant = getMantissa(str, decPos);
    378        } else {
    379            if (expPos > -1) {
    380                if (expPos > length) { // prevents double exponent causing IOOBE
    381                    throw new NumberFormatException(str + " is not a valid number.");
    382                }
    383                mant = getMantissa(str, expPos);
    384            } else {
    385                // No decimal, no exponent, but there may be a type character to remove
    386                mant = getMantissa(str, requestType ? length - 1 : length);
    387            }
    388            dec = null;
    389        }
    390        if (requestType) {
    391            if (expPos > -1 && expPos < length - 1) {
    392                exp = str.substring(expPos + 1, length - 1);
    393            } else {
    394                exp = null;
    395            }
    396            //Requesting a specific type.
    397            final String numeric = str.substring(0, length - 1);
    398            switch (lastChar) {
    399                case 'l' :
    400                case 'L' :
    401                    if (dec == null
    402                        && exp == null
    403                        && (!numeric.isEmpty() && numeric.charAt(0) == '-' && isDigits(numeric.substring(1)) || isDigits(numeric))) {
    404                        try {
    405                            return createLong(numeric);
    406                        } catch (final NumberFormatException ignored) {
    407                            // Too big for a long
    408                        }
    409                        return createBigInteger(numeric);
    410
    411                    }
    412                    throw new NumberFormatException(str + " is not a valid number.");
    413                case 'f' :
    414                case 'F' :
    415                    try {
    416                        final Float f = createFloat(str);
    417                        if (!(f.isInfinite() || f.floatValue() == 0.0F && !isZero(mant, dec))) {
    418                            //If it's too big for a float or the float value = 0 and the string
    419                            //has non-zeros in it, then float does not have the precision we want
    420                            return f;
    421                        }
    422
    423                    } catch (final NumberFormatException ignored) {
    424                        // ignore the bad number
    425                    }
    426                    //$FALL-THROUGH$
    427                case 'd' :
    428                case 'D' :
    429                    try {
    430                        final Double d = createDouble(str);
    431                        if (!(d.isInfinite() || d.doubleValue() == 0.0D && !isZero(mant, dec))) {
    432                            return d;
    433                        }
    434                    } catch (final NumberFormatException ignored) {
    435                        // ignore the bad number
    436                    }
    437                    try {
    438                        return createBigDecimal(numeric);
    439                    } catch (final NumberFormatException ignored) {
    440                        // ignore the bad number
    441                    }
    442                    //$FALL-THROUGH$
    443                default :
    444                    throw new NumberFormatException(str + " is not a valid number.");
    445
    446            }
    447        }
    448        //User doesn't have a preference on the return type, so let's start
    449        //small and go from there...
    450        if (expPos > -1 && expPos < length - 1) {
    451            exp = str.substring(expPos + 1);
    452        } else {
    453            exp = null;
    454        }
    455        if (dec == null && exp == null) { // no decimal point and no exponent
    456            //Must be an Integer, Long, Biginteger
    457            try {
    458                return createInteger(str);
    459            } catch (final NumberFormatException ignored) {
    460                // ignore the bad number
    461            }
    462            try {
    463                return createLong(str);
    464            } catch (final NumberFormatException ignored) {
    465                // ignore the bad number
    466            }
    467            return createBigInteger(str);
    468        }
    469
    470        //Must be a Float, Double, BigDecimal
    471        try {
    472            final Float f = createFloat(str);
    473            final Double d = createDouble(str);
    474            if (!f.isInfinite()
    475                    && !(f.floatValue() == 0.0F && !isZero(mant, dec))
    476                    && f.toString().equals(d.toString())) {
    477                return f;
    478            }
    479            if (!d.isInfinite() && !(d.doubleValue() == 0.0D && !isZero(mant, dec))) {
    480                final BigDecimal b = createBigDecimal(str);
    481                if (b.compareTo(BigDecimal.valueOf(d.doubleValue())) == 0) {
    482                    return d;
    483                }
    484                return b;
    485            }
    486        } catch (final NumberFormatException ignored) {
    487            // ignore the bad number
    488        }
    489        return createBigDecimal(str);
    490    }
    491
    492     /**
    493     * Utility method for {@link #createNumber(String)}.
    494     *
    495     * <p>Returns mantissa of the given number.</p>
    496     *
    497     * @param str the string representation of the number
    498     * @param stopPos the position of the exponent or decimal point
    499     * @return mantissa of the given number
    500     * @throws NumberFormatException if no mantissa can be retrieved
    501     */
    502    private static String getMantissa(final String str, final int stopPos) {
    503         final char firstChar = str.charAt(0);
    504         final boolean hasSign = firstChar == '-' || firstChar == '+';
    505         final int length = str.length();
    506         if (length <= (hasSign ? 1 : 0) || length < stopPos) {
    507             throw new NumberFormatException(str + " is not a valid number.");
    508         }
    509         return hasSign ? str.substring(1, stopPos) : str.substring(0, stopPos);
    510    }
    511
    512    /**
    513     * Utility method for {@link #createNumber(java.lang.String)}.
    514     *
    515     * <p>Returns {@code true} if s is {@code null} or empty.</p>
    516     *
    517     * @param str the String to check
    518     * @return if it is all zeros or {@code null}
    519     */
    520    private static boolean isAllZeros(final String str) {
    521        if (str == null) {
    522            return true;
    523        }
    524        for (int i = str.length() - 1; i >= 0; i--) {
    525            if (str.charAt(i) != '0') {
    526                return false;
    527            }
    528        }
    529        return true;
    530    }
    531
    532    /**
    533     * Checks whether the String is a valid Java number.
    534     *
    535     * <p>Valid numbers include hexadecimal marked with the {@code 0x} or
    536     * {@code 0X} qualifier, octal numbers, scientific notation and
    537     * numbers marked with a type qualifier (e.g. 123L).</p>
    538     *
    539     * <p>Non-hexadecimal strings beginning with a leading zero are
    540     * treated as octal values. Thus the string {@code 09} will return
    541     * {@code false}, since {@code 9} is not a valid octal value.
    542     * However, numbers beginning with {@code 0.} are treated as decimal.</p>
    543     *
    544     * <p>{@code null} and empty/blank {@link String} will return
    545     * {@code false}.</p>
    546     *
    547     * <p>Note, {@link #createNumber(String)} should return a number for every
    548     * input resulting in {@code true}.</p>
    549     *
    550     * @param str  the {@link String} to check
    551     * @return {@code true} if the string is a correctly formatted number
    552     * @since 3.5
    553     */
    554    public static boolean isCreatable(final String str) {
    555        if (StringUtils.isEmpty(str)) {
    556            return false;
    557        }
    558        final char[] chars = str.toCharArray();
    559        int sz = chars.length;
    560        boolean hasExp = false;
    561        boolean hasDecPoint = false;
    562        boolean allowSigns = false;
    563        boolean foundDigit = false;
    564        // deal with any possible sign up front
    565        final int start = chars[0] == '-' || chars[0] == '+' ? 1 : 0;
    566        if (sz > start + 1 && chars[start] == '0' && !StringUtils.contains(str, '.')) { // leading 0, skip if is a decimal number
    567            if (chars[start + 1] == 'x' || chars[start + 1] == 'X') { // leading 0x/0X
    568                int i = start + 2;
    569                if (i == sz) {
    570                    return false; // str == "0x"
    571                }
    572                // checking hex (it can't be anything else)
    573                for (; i < chars.length; i++) {
    574                    if ((chars[i] < '0' || chars[i] > '9')
    575                        && (chars[i] < 'a' || chars[i] > 'f')
    576                        && (chars[i] < 'A' || chars[i] > 'F')) {
    577                        return false;
    578                    }
    579                }
    580                return true;
    581           }
    582            if (Character.isDigit(chars[start + 1])) {
    583                   // leading 0, but not hex, must be octal
    584                   int i = start + 1;
    585                   for (; i < chars.length; i++) {
    586                       if (chars[i] < '0' || chars[i] > '7') {
    587                           return false;
    588                       }
    589                   }
    590                   return true;
    591               }
    592        }
    593        sz--; // don't want to loop to the last char, check it afterwards
    594              // for type qualifiers
    595        int i = start;
    596        // loop to the next to last char or to the last char if we need another digit to
    597        // make a valid number (e.g. chars[0..5] = "1234E")
    598        while (i < sz || i < sz + 1 && allowSigns && !foundDigit) {
    599            if (chars[i] >= '0' && chars[i] <= '9') {
    600                foundDigit = true;
    601                allowSigns = false;
    602
    603            } else if (chars[i] == '.') {
    604                if (hasDecPoint || hasExp) {
    605                    // two decimal points or dec in exponent
    606                    return false;
    607                }
    608                hasDecPoint = true;
    609            } else if (chars[i] == 'e' || chars[i] == 'E') {
    610                // we've already taken care of hex.
    611                if (hasExp) {
    612                    // two E's
    613                    return false;
    614                }
    615                if (!foundDigit) {
    616                    return false;
    617                }
    618                hasExp = true;
    619                allowSigns = true;
    620            } else if (chars[i] == '+' || chars[i] == '-') {
    621                if (!allowSigns) {
    622                    return false;
    623                }
    624                allowSigns = false;
    625                foundDigit = false; // we need a digit after the E
    626            } else {
    627                return false;
    628            }
    629            i++;
    630        }
    631        if (i < chars.length) {
    632            if (chars[i] >= '0' && chars[i] <= '9') {
    633                // no type qualifier, OK
    634                return true;
    635            }
    636            if (chars[i] == 'e' || chars[i] == 'E') {
    637                // can't have an E at the last byte
    638                return false;
    639            }
    640            if (chars[i] == '.') {
    641                if (hasDecPoint || hasExp) {
    642                    // two decimal points or dec in exponent
    643                    return false;
    644                }
    645                // single trailing decimal point after non-exponent is ok
    646                return foundDigit;
    647            }
    648            if (!allowSigns
    649                && (chars[i] == 'd'
    650                    || chars[i] == 'D'
    651                    || chars[i] == 'f'
    652                    || chars[i] == 'F')) {
    653                return foundDigit;
    654            }
    655            if (chars[i] == 'l'
    656                || chars[i] == 'L') {
    657                // not allowing L with an exponent or decimal point
    658                return foundDigit && !hasExp && !hasDecPoint;
    659            }
    660            // last character is illegal
    661            return false;
    662        }
    663        // allowSigns is true iff the val ends in 'E'
    664        // found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
    665        return !allowSigns && foundDigit;
    666    }
    667
    668    /**
    669     * Checks whether the {@link String} contains only
    670     * digit characters.
    671     *
    672     * <p>{@code null} and empty String will return
    673     * {@code false}.</p>
    674     *
    675     * @param str  the {@link String} to check
    676     * @return {@code true} if str contains only Unicode numeric
    677     */
    678    public static boolean isDigits(final String str) {
    679        return StringUtils.isNumeric(str);
    680    }
    681
    682    /**
    683     * Checks whether the String is a valid Java number.
    684     *
    685     * <p>Valid numbers include hexadecimal marked with the {@code 0x} or
    686     * {@code 0X} qualifier, octal numbers, scientific notation and
    687     * numbers marked with a type qualifier (e.g. 123L).</p>
    688     *
    689     * <p>Non-hexadecimal strings beginning with a leading zero are
    690     * treated as octal values. Thus the string {@code 09} will return
    691     * {@code false}, since {@code 9} is not a valid octal value.
    692     * However, numbers beginning with {@code 0.} are treated as decimal.</p>
    693     *
    694     * <p>{@code null} and empty/blank {@link String} will return
    695     * {@code false}.</p>
    696     *
    697     * <p>Note, {@link #createNumber(String)} should return a number for every
    698     * input resulting in {@code true}.</p>
    699     *
    700     * @param str  the {@link String} to check
    701     * @return {@code true} if the string is a correctly formatted number
    702     * @since 3.3 the code supports hexadecimal {@code 0Xhhh} an
    703     *        octal {@code 0ddd} validation
    704     * @deprecated This feature will be removed in Lang 4,
    705     *             use {@link NumberUtils#isCreatable(String)} instead
    706     */
    707    @Deprecated
    708    public static boolean isNumber(final String str) {
    709        return isCreatable(str);
    710    }
    711
    712    /**
    713     * Checks whether the given String is a parsable number.
    714     *
    715     * <p>Parsable numbers include those Strings understood by {@link Integer#parseInt(String)},
    716     * {@link Long#parseLong(String)}, {@link Float#parseFloat(String)} or
    717     * {@link Double#parseDouble(String)}. This method can be used instead of catching {@link java.text.ParseException}
    718     * when calling one of those methods.</p>
    719     *
    720     * <p>Hexadecimal and scientific notations are <strong>not</strong> considered parsable.
    721     * See {@link #isCreatable(String)} on those cases.</p>
    722     *
    723     * <p>{@code null} and empty String will return {@code false}.</p>
    724     *
    725     * @param str the String to check.
    726     * @return {@code true} if the string is a parsable number.
    727     * @since 3.4
    728     */
    729    public static boolean isParsable(final String str) {
    730        if (StringUtils.isEmpty(str)) {
    731            return false;
    732        }
    733        if (str.charAt(str.length() - 1) == '.') {
    734            return false;
    735        }
    736        if (str.charAt(0) == '-') {
    737            if (str.length() == 1) {
    738                return false;
    739            }
    740            return withDecimalsParsing(str, 1);
    741        }
    742        return withDecimalsParsing(str, 0);
    743    }
    744
    745    /**
    746     * Utility method for {@link #createNumber(java.lang.String)}.
    747     *
    748     * <p>This will check if the magnitude of the number is zero by checking if there
    749     * are only zeros before and after the decimal place.</p>
    750     *
    751     * <p>Note: It is <strong>assumed</strong> that the input string has been converted
    752     * to either a Float or Double with a value of zero when this method is called.
    753     * This eliminates invalid input for example {@code ".", ".D", ".e0"}.</p>
    754     *
    755     * <p>Thus the method only requires checking if both arguments are null, empty or
    756     * contain only zeros.</p>
    757     *
    758     * <p>Given {@code s = mant + "." + dec}:</p>
    759     * <ul>
    760     * <li>{@code true} if s is {@code "0.0"}
    761     * <li>{@code true} if s is {@code "0."}
    762     * <li>{@code true} if s is {@code ".0"}
    763     * <li>{@code false} otherwise (this assumes {@code "."} is not possible)
    764     * </ul>
    765     *
    766     * @param mant the mantissa decimal digits before the decimal point (sign must be removed; never null)
    767     * @param dec the decimal digits after the decimal point (exponent and type specifier removed;
    768     *            can be null)
    769     * @return true if the magnitude is zero
    770     */
    771    private static boolean isZero(final String mant, final String dec) {
    772        return isAllZeros(mant) && isAllZeros(dec);
    773    }
    774
    775    /**
    776     * Returns the maximum value in an array.
    777     *
    778     * @param array  an array, must not be null or empty
    779     * @return the maximum value in the array
    780     * @throws NullPointerException if {@code array} is {@code null}
    781     * @throws IllegalArgumentException if {@code array} is empty
    782     * @since 3.4 Changed signature from max(byte[]) to max(byte...)
    783     */
    784    public static byte max(final byte... array) {
    785        // Validates input
    786        validateArray(array);
    787
    788        // Finds and returns max
    789        byte max = array[0];
    790        for (int i = 1; i < array.length; i++) {
    791            if (array[i] > max) {
    792                max = array[i];
    793            }
    794        }
    795
    796        return max;
    797    }
    798
    799    /**
    800     * Gets the maximum of three {@code byte} values.
    801     *
    802     * @param a  value 1
    803     * @param b  value 2
    804     * @param c  value 3
    805     * @return  the largest of the values
    806     */
    807    public static byte max(byte a, final byte b, final byte c) {
    808        if (b > a) {
    809            a = b;
    810        }
    811        if (c > a) {
    812            a = c;
    813        }
    814        return a;
    815    }
    816
    817    /**
    818     * Returns the maximum value in an array.
    819     *
    820     * @param array  an array, must not be null or empty
    821     * @return the maximum value in the array
    822     * @throws NullPointerException if {@code array} is {@code null}
    823     * @throws IllegalArgumentException if {@code array} is empty
    824     * @see IEEE754rUtils#max(double[]) IEEE754rUtils for a version of this method that handles NaN differently
    825     * @since 3.4 Changed signature from max(double[]) to max(double...)
    826     */
    827    public static double max(final double... array) {
    828        // Validates input
    829        validateArray(array);
    830
    831        // Finds and returns max
    832        double max = array[0];
    833        for (int j = 1; j < array.length; j++) {
    834            if (Double.isNaN(array[j])) {
    835                return Double.NaN;
    836            }
    837            if (array[j] > max) {
    838                max = array[j];
    839            }
    840        }
    841
    842        return max;
    843    }
    844
    845    /**
    846     * Gets the maximum of three {@code double} values.
    847     *
    848     * <p>If any value is {@code NaN}, {@code NaN} is
    849     * returned. Infinity is handled.</p>
    850     *
    851     * @param a  value 1
    852     * @param b  value 2
    853     * @param c  value 3
    854     * @return  the largest of the values
    855     * @see IEEE754rUtils#max(double, double, double) for a version of this method that handles NaN differently
    856     */
    857    public static double max(final double a, final double b, final double c) {
    858        return Math.max(Math.max(a, b), c);
    859    }
    860
    861    /**
    862     * Returns the maximum value in an array.
    863     *
    864     * @param array  an array, must not be null or empty
    865     * @return the maximum value in the array
    866     * @throws NullPointerException if {@code array} is {@code null}
    867     * @throws IllegalArgumentException if {@code array} is empty
    868     * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this method that handles NaN differently
    869     * @since 3.4 Changed signature from max(float[]) to max(float...)
    870     */
    871    public static float max(final float... array) {
    872        // Validates input
    873        validateArray(array);
    874
    875        // Finds and returns max
    876        float max = array[0];
    877        for (int j = 1; j < array.length; j++) {
    878            if (Float.isNaN(array[j])) {
    879                return Float.NaN;
    880            }
    881            if (array[j] > max) {
    882                max = array[j];
    883            }
    884        }
    885
    886        return max;
    887    }
    888
    889    // must handle Long, Float, Integer, Float, Short,
    890    //                  BigDecimal, BigInteger and Byte
    891    // useful methods:
    892    // Byte.decode(String)
    893    // Byte.valueOf(String, int radix)
    894    // Byte.valueOf(String)
    895    // Double.valueOf(String)
    896    // Float.valueOf(String)
    897    // Float.valueOf(String)
    898    // Integer.valueOf(String, int radix)
    899    // Integer.valueOf(String)
    900    // Integer.decode(String)
    901    // Integer.getInteger(String)
    902    // Integer.getInteger(String, int val)
    903    // Integer.getInteger(String, Integer val)
    904    // Integer.valueOf(String)
    905    // Double.valueOf(String)
    906    // new Byte(String)
    907    // Long.valueOf(String)
    908    // Long.getLong(String)
    909    // Long.getLong(String, int)
    910    // Long.getLong(String, Integer)
    911    // Long.valueOf(String, int)
    912    // Long.valueOf(String)
    913    // Short.valueOf(String)
    914    // Short.decode(String)
    915    // Short.valueOf(String, int)
    916    // Short.valueOf(String)
    917    // new BigDecimal(String)
    918    // new BigInteger(String)
    919    // new BigInteger(String, int radix)
    920    // Possible inputs:
    921    // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
    922    // plus minus everything. Prolly more. A lot are not separable.
    923
    924    /**
    925     * Gets the maximum of three {@code float} values.
    926     *
    927     * <p>If any value is {@code NaN}, {@code NaN} is
    928     * returned. Infinity is handled.</p>
    929     *
    930     * @param a  value 1
    931     * @param b  value 2
    932     * @param c  value 3
    933     * @return  the largest of the values
    934     * @see IEEE754rUtils#max(float, float, float) for a version of this method that handles NaN differently
    935     */
    936    public static float max(final float a, final float b, final float c) {
    937        return Math.max(Math.max(a, b), c);
    938    }
    939
    940    /**
    941     * Returns the maximum value in an array.
    942     *
    943     * @param array  an array, must not be null or empty
    944     * @return the maximum value in the array
    945     * @throws NullPointerException if {@code array} is {@code null}
    946     * @throws IllegalArgumentException if {@code array} is empty
    947     * @since 3.4 Changed signature from max(int[]) to max(int...)
    948     */
    949    public static int max(final int... array) {
    950        // Validates input
    951        validateArray(array);
    952
    953        // Finds and returns max
    954        int max = array[0];
    955        for (int j = 1; j < array.length; j++) {
    956            if (array[j] > max) {
    957                max = array[j];
    958            }
    959        }
    960
    961        return max;
    962    }
    963
    964    /**
    965     * Gets the maximum of three {@code int} values.
    966     *
    967     * @param a  value 1
    968     * @param b  value 2
    969     * @param c  value 3
    970     * @return  the largest of the values
    971     */
    972    public static int max(int a, final int b, final int c) {
    973        if (b > a) {
    974            a = b;
    975        }
    976        if (c > a) {
    977            a = c;
    978        }
    979        return a;
    980    }
    981
    982    /**
    983     * Returns the maximum value in an array.
    984     *
    985     * @param array  an array, must not be null or empty
    986     * @return the maximum value in the array
    987     * @throws NullPointerException if {@code array} is {@code null}
    988     * @throws IllegalArgumentException if {@code array} is empty
    989     * @since 3.4 Changed signature from max(long[]) to max(long...)
    990     */
    991    public static long max(final long... array) {
    992        // Validates input
    993        validateArray(array);
    994
    995        // Finds and returns max
    996        long max = array[0];
    997        for (int j = 1; j < array.length; j++) {
    998            if (array[j] > max) {
    999                max = array[j];
    1000            }
    1001        }
    1002
    1003        return max;
    1004    }
    1005
    1006    // 3 param max
    1007    /**
    1008     * Gets the maximum of three {@code long} values.
    1009     *
    1010     * @param a  value 1
    1011     * @param b  value 2
    1012     * @param c  value 3
    1013     * @return  the largest of the values
    1014     */
    1015    public static long max(long a, final long b, final long c) {
    1016        if (b > a) {
    1017            a = b;
    1018        }
    1019        if (c > a) {
    1020            a = c;
    1021        }
    1022        return a;
    1023    }
    1024
    1025    /**
    1026     * Returns the maximum value in an array.
    1027     *
    1028     * @param array  an array, must not be null or empty
    1029     * @return the maximum value in the array
    1030     * @throws NullPointerException if {@code array} is {@code null}
    1031     * @throws IllegalArgumentException if {@code array} is empty
    1032     * @since 3.4 Changed signature from max(short[]) to max(short...)
    1033     */
    1034    public static short max(final short... array) {
    1035        // Validates input
    1036        validateArray(array);
    1037
    1038        // Finds and returns max
    1039        short max = array[0];
    1040        for (int i = 1; i < array.length; i++) {
    1041            if (array[i] > max) {
    1042                max = array[i];
    1043            }
    1044        }
    1045
    1046        return max;
    1047    }
    1048
    1049    /**
    1050     * Gets the maximum of three {@code short} values.
    1051     *
    1052     * @param a  value 1
    1053     * @param b  value 2
    1054     * @param c  value 3
    1055     * @return  the largest of the values
    1056     */
    1057    public static short max(short a, final short b, final short c) {
    1058        if (b > a) {
    1059            a = b;
    1060        }
    1061        if (c > a) {
    1062            a = c;
    1063        }
    1064        return a;
    1065    }
    1066
    1067    /**
    1068     * Returns the minimum value in an array.
    1069     *
    1070     * @param array  an array, must not be null or empty
    1071     * @return the minimum value in the array
    1072     * @throws NullPointerException if {@code array} is {@code null}
    1073     * @throws IllegalArgumentException if {@code array} is empty
    1074     * @since 3.4 Changed signature from min(byte[]) to min(byte...)
    1075     */
    1076    public static byte min(final byte... array) {
    1077        // Validates input
    1078        validateArray(array);
    1079
    1080        // Finds and returns min
    1081        byte min = array[0];
    1082        for (int i = 1; i < array.length; i++) {
    1083            if (array[i] < min) {
    1084                min = array[i];
    1085            }
    1086        }
    1087
    1088        return min;
    1089    }
    1090
    1091    /**
    1092     * Gets the minimum of three {@code byte} values.
    1093     *
    1094     * @param a  value 1
    1095     * @param b  value 2
    1096     * @param c  value 3
    1097     * @return  the smallest of the values
    1098     */
    1099    public static byte min(byte a, final byte b, final byte c) {
    1100        if (b < a) {
    1101            a = b;
    1102        }
    1103        if (c < a) {
    1104            a = c;
    1105        }
    1106        return a;
    1107    }
    1108
    1109    /**
    1110     * Returns the minimum value in an array.
    1111     *
    1112     * @param array  an array, must not be null or empty
    1113     * @return the minimum value in the array
    1114     * @throws NullPointerException if {@code array} is {@code null}
    1115     * @throws IllegalArgumentException if {@code array} is empty
    1116     * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this method that handles NaN differently
    1117     * @since 3.4 Changed signature from min(double[]) to min(double...)
    1118     */
    1119    public static double min(final double... array) {
    1120        // Validates input
    1121        validateArray(array);
    1122
    1123        // Finds and returns min
    1124        double min = array[0];
    1125        for (int i = 1; i < array.length; i++) {
    1126            if (Double.isNaN(array[i])) {
    1127                return Double.NaN;
    1128            }
    1129            if (array[i] < min) {
    1130                min = array[i];
    1131            }
    1132        }
    1133
    1134        return min;
    1135    }
    1136
    1137    /**
    1138     * Gets the minimum of three {@code double} values.
    1139     *
    1140     * <p>If any value is {@code NaN}, {@code NaN} is
    1141     * returned. Infinity is handled.</p>
    1142     *
    1143     * @param a  value 1
    1144     * @param b  value 2
    1145     * @param c  value 3
    1146     * @return  the smallest of the values
    1147     * @see IEEE754rUtils#min(double, double, double) for a version of this method that handles NaN differently
    1148     */
    1149    public static double min(final double a, final double b, final double c) {
    1150        return Math.min(Math.min(a, b), c);
    1151    }
    1152
    1153    /**
    1154     * Returns the minimum value in an array.
    1155     *
    1156     * @param array  an array, must not be null or empty
    1157     * @return the minimum value in the array
    1158     * @throws NullPointerException if {@code array} is {@code null}
    1159     * @throws IllegalArgumentException if {@code array} is empty
    1160     * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this method that handles NaN differently
    1161     * @since 3.4 Changed signature from min(float[]) to min(float...)
    1162     */
    1163    public static float min(final float... array) {
    1164        // Validates input
    1165        validateArray(array);
    1166
    1167        // Finds and returns min
    1168        float min = array[0];
    1169        for (int i = 1; i < array.length; i++) {
    1170            if (Float.isNaN(array[i])) {
    1171                return Float.NaN;
    1172            }
    1173            if (array[i] < min) {
    1174                min = array[i];
    1175            }
    1176        }
    1177
    1178        return min;
    1179    }
    1180
    1181    /**
    1182     * Gets the minimum of three {@code float} values.
    1183     *
    1184     * <p>If any value is {@code NaN}, {@code NaN} is
    1185     * returned. Infinity is handled.</p>
    1186     *
    1187     * @param a  value 1
    1188     * @param b  value 2
    1189     * @param c  value 3
    1190     * @return  the smallest of the values
    1191     * @see IEEE754rUtils#min(float, float, float) for a version of this method that handles NaN differently
    1192     */
    1193    public static float min(final float a, final float b, final float c) {
    1194        return Math.min(Math.min(a, b), c);
    1195    }
    1196
    1197    /**
    1198     * Returns the minimum value in an array.
    1199     *
    1200     * @param array  an array, must not be null or empty
    1201     * @return the minimum value in the array
    1202     * @throws NullPointerException if {@code array} is {@code null}
    1203     * @throws IllegalArgumentException if {@code array} is empty
    1204     * @since 3.4 Changed signature from min(int[]) to min(int...)
    1205     */
    1206    public static int min(final int... array) {
    1207        // Validates input
    1208        validateArray(array);
    1209
    1210        // Finds and returns min
    1211        int min = array[0];
    1212        for (int j = 1; j < array.length; j++) {
    1213            if (array[j] < min) {
    1214                min = array[j];
    1215            }
    1216        }
    1217
    1218        return min;
    1219    }
    1220
    1221     /**
    1222     * Gets the minimum of three {@code int} values.
    1223     *
    1224     * @param a  value 1
    1225     * @param b  value 2
    1226     * @param c  value 3
    1227     * @return  the smallest of the values
    1228     */
    1229    public static int min(int a, final int b, final int c) {
    1230        if (b < a) {
    1231            a = b;
    1232        }
    1233        if (c < a) {
    1234            a = c;
    1235        }
    1236        return a;
    1237    }
    1238
    1239    /**
    1240     * Returns the minimum value in an array.
    1241     *
    1242     * @param array  an array, must not be null or empty
    1243     * @return the minimum value in the array
    1244     * @throws NullPointerException if {@code array} is {@code null}
    1245     * @throws IllegalArgumentException if {@code array} is empty
    1246     * @since 3.4 Changed signature from min(long[]) to min(long...)
    1247     */
    1248    public static long min(final long... array) {
    1249        // Validates input
    1250        validateArray(array);
    1251
    1252        // Finds and returns min
    1253        long min = array[0];
    1254        for (int i = 1; i < array.length; i++) {
    1255            if (array[i] < min) {
    1256                min = array[i];
    1257            }
    1258        }
    1259
    1260        return min;
    1261    }
    1262
    1263    // 3 param min
    1264    /**
    1265     * Gets the minimum of three {@code long} values.
    1266     *
    1267     * @param a  value 1
    1268     * @param b  value 2
    1269     * @param c  value 3
    1270     * @return  the smallest of the values
    1271     */
    1272    public static long min(long a, final long b, final long c) {
    1273        if (b < a) {
    1274            a = b;
    1275        }
    1276        if (c < a) {
    1277            a = c;
    1278        }
    1279        return a;
    1280    }
    1281
    1282    /**
    1283     * Returns the minimum value in an array.
    1284     *
    1285     * @param array  an array, must not be null or empty
    1286     * @return the minimum value in the array
    1287     * @throws NullPointerException if {@code array} is {@code null}
    1288     * @throws IllegalArgumentException if {@code array} is empty
    1289     * @since 3.4 Changed signature from min(short[]) to min(short...)
    1290     */
    1291    public static short min(final short... array) {
    1292        // Validates input
    1293        validateArray(array);
    1294
    1295        // Finds and returns min
    1296        short min = array[0];
    1297        for (int i = 1; i < array.length; i++) {
    1298            if (array[i] < min) {
    1299                min = array[i];
    1300            }
    1301        }
    1302
    1303        return min;
    1304    }
    1305
    1306    /**
    1307     * Gets the minimum of three {@code short} values.
    1308     *
    1309     * @param a  value 1
    1310     * @param b  value 2
    1311     * @param c  value 3
    1312     * @return  the smallest of the values
    1313     */
    1314    public static short min(short a, final short b, final short c) {
    1315        if (b < a) {
    1316            a = b;
    1317        }
    1318        if (c < a) {
    1319            a = c;
    1320        }
    1321        return a;
    1322    }
    1323
    1324    /**
    1325     * Convert a {@link String} to a {@code byte}, returning
    1326     * {@code zero} if the conversion fails.
    1327     *
    1328     * <p>If the string is {@code null}, {@code zero} is returned.</p>
    1329     *
    1330     * <pre>
    1331     *   NumberUtils.toByte(null) = 0
    1332     *   NumberUtils.toByte("")   = 0
    1333     *   NumberUtils.toByte("1")  = 1
    1334     * </pre>
    1335     *
    1336     * @param str  the string to convert, may be null
    1337     * @return the byte represented by the string, or {@code zero} if
    1338     *  conversion fails
    1339     * @since 2.5
    1340     */
    1341    public static byte toByte(final String str) {
    1342        return toByte(str, (byte) 0);
    1343    }
    1344
    1345    /**
    1346     * Convert a {@link String} to a {@code byte}, returning a
    1347     * default value if the conversion fails.
    1348     *
    1349     * <p>If the string is {@code null}, the default value is returned.</p>
    1350     *
    1351     * <pre>
    1352     *   NumberUtils.toByte(null, 1) = 1
    1353     *   NumberUtils.toByte("", 1)   = 1
    1354     *   NumberUtils.toByte("1", 0)  = 1
    1355     * </pre>
    1356     *
    1357     * @param str  the string to convert, may be null
    1358     * @param defaultValue  the default value
    1359     * @return the byte represented by the string, or the default if conversion fails
    1360     * @since 2.5
    1361     */
    1362    public static byte toByte(final String str, final byte defaultValue) {
    1363        if (str == null) {
    1364            return defaultValue;
    1365        }
    1366        try {
    1367            return Byte.parseByte(str);
    1368        } catch (final NumberFormatException nfe) {
    1369            return defaultValue;
    1370        }
    1371    }
    1372
    1373    /**
    1374     * Convert a {@link BigDecimal} to a {@code double}.
    1375     *
    1376     * <p>If the {@link BigDecimal} {@code value} is
    1377     * {@code null}, then the specified default value is returned.</p>
    1378     *
    1379     * <pre>
    1380     *   NumberUtils.toDouble(null)                     = 0.0d
    1381     *   NumberUtils.toDouble(BigDecimal.valueOf(8.5d)) = 8.5d
    1382     * </pre>
    1383     *
    1384     * @param value the {@link BigDecimal} to convert, may be {@code null}.
    1385     * @return the double represented by the {@link BigDecimal} or
    1386     *  {@code 0.0d} if the {@link BigDecimal} is {@code null}.
    1387     * @since 3.8
    1388     */
    1389    public static double toDouble(final BigDecimal value) {
    1390        return toDouble(value, 0.0d);
    1391    }
    1392
    1393    /**
    1394     * Convert a {@link BigDecimal} to a {@code double}.
    1395     *
    1396     * <p>If the {@link BigDecimal} {@code value} is
    1397     * {@code null}, then the specified default value is returned.</p>
    1398     *
    1399     * <pre>
    1400     *   NumberUtils.toDouble(null, 1.1d)                     = 1.1d
    1401     *   NumberUtils.toDouble(BigDecimal.valueOf(8.5d), 1.1d) = 8.5d
    1402     * </pre>
    1403     *
    1404     * @param value the {@link BigDecimal} to convert, may be {@code null}.
    1405     * @param defaultValue the default value
    1406     * @return the double represented by the {@link BigDecimal} or the
    1407     *  defaultValue if the {@link BigDecimal} is {@code null}.
    1408     * @since 3.8
    1409     */
    1410    public static double toDouble(final BigDecimal value, final double defaultValue) {
    1411        return value == null ? defaultValue : value.doubleValue();
    1412    }
    1413
    1414    /**
    1415     * Convert a {@link String} to a {@code double}, returning
    1416     * {@code 0.0d} if the conversion fails.
    1417     *
    1418     * <p>If the string {@code str} is {@code null},
    1419     * {@code 0.0d} is returned.</p>
    1420     *
    1421     * <pre>
    1422     *   NumberUtils.toDouble(null)   = 0.0d
    1423     *   NumberUtils.toDouble("")     = 0.0d
    1424     *   NumberUtils.toDouble("1.5")  = 1.5d
    1425     * </pre>
    1426     *
    1427     * @param str the string to convert, may be {@code null}
    1428     * @return the double represented by the string, or {@code 0.0d}
    1429     *  if conversion fails
    1430     * @since 2.1
    1431     */
    1432    public static double toDouble(final String str) {
    1433        return toDouble(str, 0.0d);
    1434    }
    1435
    1436    /**
    1437     * Convert a {@link String} to a {@code double}, returning a
    1438     * default value if the conversion fails.
    1439     *
    1440     * <p>If the string {@code str} is {@code null}, the default
    1441     * value is returned.</p>
    1442     *
    1443     * <pre>
    1444     *   NumberUtils.toDouble(null, 1.1d)   = 1.1d
    1445     *   NumberUtils.toDouble("", 1.1d)     = 1.1d
    1446     *   NumberUtils.toDouble("1.5", 0.0d)  = 1.5d
    1447     * </pre>
    1448     *
    1449     * @param str the string to convert, may be {@code null}
    1450     * @param defaultValue the default value
    1451     * @return the double represented by the string, or defaultValue
    1452     *  if conversion fails
    1453     * @since 2.1
    1454     */
    1455    public static double toDouble(final String str, final double defaultValue) {
    1456      if (str == null) {
    1457          return defaultValue;
    1458      }
    1459      try {
    1460          return Double.parseDouble(str);
    1461      } catch (final NumberFormatException nfe) {
    1462          return defaultValue;
    1463      }
    1464    }
    1465
    1466    /**
    1467     * Convert a {@link String} to a {@code float}, returning
    1468     * {@code 0.0f} if the conversion fails.
    1469     *
    1470     * <p>If the string {@code str} is {@code null},
    1471     * {@code 0.0f} is returned.</p>
    1472     *
    1473     * <pre>
    1474     *   NumberUtils.toFloat(null)   = 0.0f
    1475     *   NumberUtils.toFloat("")     = 0.0f
    1476     *   NumberUtils.toFloat("1.5")  = 1.5f
    1477     * </pre>
    1478     *
    1479     * @param str the string to convert, may be {@code null}
    1480     * @return the float represented by the string, or {@code 0.0f}
    1481     *  if conversion fails
    1482     * @since 2.1
    1483     */
    1484    public static float toFloat(final String str) {
    1485        return toFloat(str, 0.0f);
    1486    }
    1487
    1488    /**
    1489     * Convert a {@link String} to a {@code float}, returning a
    1490     * default value if the conversion fails.
    1491     *
    1492     * <p>If the string {@code str} is {@code null}, the default
    1493     * value is returned.</p>
    1494     *
    1495     * <pre>
    1496     *   NumberUtils.toFloat(null, 1.1f)   = 1.1f
    1497     *   NumberUtils.toFloat("", 1.1f)     = 1.1f
    1498     *   NumberUtils.toFloat("1.5", 0.0f)  = 1.5f
    1499     * </pre>
    1500     *
    1501     * @param str the string to convert, may be {@code null}
    1502     * @param defaultValue the default value
    1503     * @return the float represented by the string, or defaultValue
    1504     *  if conversion fails
    1505     * @since 2.1
    1506     */
    1507    public static float toFloat(final String str, final float defaultValue) {
    1508      if (str == null) {
    1509          return defaultValue;
    1510      }
    1511      try {
    1512          return Float.parseFloat(str);
    1513      } catch (final NumberFormatException nfe) {
    1514          return defaultValue;
    1515      }
    1516    }
    1517
    1518    /**
    1519     * Convert a {@link String} to an {@code int}, returning
    1520     * {@code zero} if the conversion fails.
    1521     *
    1522     * <p>If the string is {@code null}, {@code zero} is returned.</p>
    1523     *
    1524     * <pre>
    1525     *   NumberUtils.toInt(null) = 0
    1526     *   NumberUtils.toInt("")   = 0
    1527     *   NumberUtils.toInt("1")  = 1
    1528     * </pre>
    1529     *
    1530     * @param str  the string to convert, may be null
    1531     * @return the int represented by the string, or {@code zero} if
    1532     *  conversion fails
    1533     * @since 2.1
    1534     */
    1535    public static int toInt(final String str) {
    1536        return toInt(str, 0);
    1537    }
    1538
    1539    /**
    1540     * Convert a {@link String} to an {@code int}, returning a
    1541     * default value if the conversion fails.
    1542     *
    1543     * <p>If the string is {@code null}, the default value is returned.</p>
    1544     *
    1545     * <pre>
    1546     *   NumberUtils.toInt(null, 1) = 1
    1547     *   NumberUtils.toInt("", 1)   = 1
    1548     *   NumberUtils.toInt("1", 0)  = 1
    1549     * </pre>
    1550     *
    1551     * @param str  the string to convert, may be null
    1552     * @param defaultValue  the default value
    1553     * @return the int represented by the string, or the default if conversion fails
    1554     * @since 2.1
    1555     */
    1556    public static int toInt(final String str, final int defaultValue) {
    1557        if (str == null) {
    1558            return defaultValue;
    1559        }
    1560        try {
    1561            return Integer.parseInt(str);
    1562        } catch (final NumberFormatException nfe) {
    1563            return defaultValue;
    1564        }
    1565    }
    1566
    1567    /**
    1568     * Convert a {@link String} to a {@code long}, returning
    1569     * {@code zero} if the conversion fails.
    1570     *
    1571     * <p>If the string is {@code null}, {@code zero} is returned.</p>
    1572     *
    1573     * <pre>
    1574     *   NumberUtils.toLong(null) = 0L
    1575     *   NumberUtils.toLong("")   = 0L
    1576     *   NumberUtils.toLong("1")  = 1L
    1577     * </pre>
    1578     *
    1579     * @param str  the string to convert, may be null
    1580     * @return the long represented by the string, or {@code 0} if
    1581     *  conversion fails
    1582     * @since 2.1
    1583     */
    1584    public static long toLong(final String str) {
    1585        return toLong(str, 0L);
    1586    }
    1587
    1588    /**
    1589     * Convert a {@link String} to a {@code long}, returning a
    1590     * default value if the conversion fails.
    1591     *
    1592     * <p>If the string is {@code null}, the default value is returned.</p>
    1593     *
    1594     * <pre>
    1595     *   NumberUtils.toLong(null, 1L) = 1L
    1596     *   NumberUtils.toLong("", 1L)   = 1L
    1597     *   NumberUtils.toLong("1", 0L)  = 1L
    1598     * </pre>
    1599     *
    1600     * @param str  the string to convert, may be null
    1601     * @param defaultValue  the default value
    1602     * @return the long represented by the string, or the default if conversion fails
    1603     * @since 2.1
    1604     */
    1605    public static long toLong(final String str, final long defaultValue) {
    1606        if (str == null) {
    1607            return defaultValue;
    1608        }
    1609        try {
    1610            return Long.parseLong(str);
    1611        } catch (final NumberFormatException nfe) {
    1612            return defaultValue;
    1613        }
    1614    }
    1615
    1616    /**
    1617     * Convert a {@link BigDecimal} to a {@link BigDecimal} with a scale of
    1618     * two that has been rounded using {@code RoundingMode.HALF_EVEN}. If the supplied
    1619     * {@code value} is null, then {@code BigDecimal.ZERO} is returned.
    1620     *
    1621     * <p>Note, the scale of a {@link BigDecimal} is the number of digits to the right of the
    1622     * decimal point.</p>
    1623     *
    1624     * @param value the {@link BigDecimal} to convert, may be null.
    1625     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1626     * @since 3.8
    1627     */
    1628    public static BigDecimal toScaledBigDecimal(final BigDecimal value) {
    1629        return toScaledBigDecimal(value, INTEGER_TWO, RoundingMode.HALF_EVEN);
    1630    }
    1631
    1632    /**
    1633     * Convert a {@link BigDecimal} to a {@link BigDecimal} whose scale is the
    1634     * specified value with a {@link RoundingMode} applied. If the input {@code value}
    1635     * is {@code null}, we simply return {@code BigDecimal.ZERO}.
    1636     *
    1637     * @param value the {@link BigDecimal} to convert, may be null.
    1638     * @param scale the number of digits to the right of the decimal point.
    1639     * @param roundingMode a rounding behavior for numerical operations capable of
    1640     *  discarding precision.
    1641     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1642     * @since 3.8
    1643     */
    1644    public static BigDecimal toScaledBigDecimal(final BigDecimal value, final int scale, final RoundingMode roundingMode) {
    1645        if (value == null) {
    1646            return BigDecimal.ZERO;
    1647        }
    1648        return value.setScale(
    1649            scale,
    1650            roundingMode == null ? RoundingMode.HALF_EVEN : roundingMode
    1651        );
    1652    }
    1653
    1654    /**
    1655     * Convert a {@link Double} to a {@link BigDecimal} with a scale of
    1656     * two that has been rounded using {@code RoundingMode.HALF_EVEN}. If the supplied
    1657     * {@code value} is null, then {@code BigDecimal.ZERO} is returned.
    1658     *
    1659     * <p>Note, the scale of a {@link BigDecimal} is the number of digits to the right of the
    1660     * decimal point.</p>
    1661     *
    1662     * @param value the {@link Double} to convert, may be null.
    1663     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1664     * @since 3.8
    1665     */
    1666    public static BigDecimal toScaledBigDecimal(final Double value) {
    1667        return toScaledBigDecimal(value, INTEGER_TWO, RoundingMode.HALF_EVEN);
    1668    }
    1669
    1670    /**
    1671     * Convert a {@link Double} to a {@link BigDecimal} whose scale is the
    1672     * specified value with a {@link RoundingMode} applied. If the input {@code value}
    1673     * is {@code null}, we simply return {@code BigDecimal.ZERO}.
    1674     *
    1675     * @param value the {@link Double} to convert, may be null.
    1676     * @param scale the number of digits to the right of the decimal point.
    1677     * @param roundingMode a rounding behavior for numerical operations capable of
    1678     *  discarding precision.
    1679     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1680     * @since 3.8
    1681     */
    1682    public static BigDecimal toScaledBigDecimal(final Double value, final int scale, final RoundingMode roundingMode) {
    1683        if (value == null) {
    1684            return BigDecimal.ZERO;
    1685        }
    1686        return toScaledBigDecimal(
    1687            BigDecimal.valueOf(value),
    1688            scale,
    1689            roundingMode
    1690        );
    1691    }
    1692
    1693    /**
    1694     * Convert a {@link Float} to a {@link BigDecimal} with a scale of
    1695     * two that has been rounded using {@code RoundingMode.HALF_EVEN}. If the supplied
    1696     * {@code value} is null, then {@code BigDecimal.ZERO} is returned.
    1697     *
    1698     * <p>Note, the scale of a {@link BigDecimal} is the number of digits to the right of the
    1699     * decimal point.</p>
    1700     *
    1701     * @param value the {@link Float} to convert, may be null.
    1702     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1703     * @since 3.8
    1704     */
    1705    public static BigDecimal toScaledBigDecimal(final Float value) {
    1706        return toScaledBigDecimal(value, INTEGER_TWO, RoundingMode.HALF_EVEN);
    1707    }
    1708
    1709    /**
    1710     * Convert a {@link Float} to a {@link BigDecimal} whose scale is the
    1711     * specified value with a {@link RoundingMode} applied. If the input {@code value}
    1712     * is {@code null}, we simply return {@code BigDecimal.ZERO}.
    1713     *
    1714     * @param value the {@link Float} to convert, may be null.
    1715     * @param scale the number of digits to the right of the decimal point.
    1716     * @param roundingMode a rounding behavior for numerical operations capable of
    1717     *  discarding precision.
    1718     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1719     * @since 3.8
    1720     */
    1721    public static BigDecimal toScaledBigDecimal(final Float value, final int scale, final RoundingMode roundingMode) {
    1722        if (value == null) {
    1723            return BigDecimal.ZERO;
    1724        }
    1725        return toScaledBigDecimal(
    1726            BigDecimal.valueOf(value),
    1727            scale,
    1728            roundingMode
    1729        );
    1730    }
    1731
    1732    /**
    1733     * Convert a {@link String} to a {@link BigDecimal} with a scale of
    1734     * two that has been rounded using {@code RoundingMode.HALF_EVEN}. If the supplied
    1735     * {@code value} is null, then {@code BigDecimal.ZERO} is returned.
    1736     *
    1737     * <p>Note, the scale of a {@link BigDecimal} is the number of digits to the right of the
    1738     * decimal point.</p>
    1739     *
    1740     * @param value the {@link String} to convert, may be null.
    1741     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1742     * @since 3.8
    1743     */
    1744    public static BigDecimal toScaledBigDecimal(final String value) {
    1745        return toScaledBigDecimal(value, INTEGER_TWO, RoundingMode.HALF_EVEN);
    1746    }
    1747
    1748    /**
    1749     * Convert a {@link String} to a {@link BigDecimal} whose scale is the
    1750     * specified value with a {@link RoundingMode} applied. If the input {@code value}
    1751     * is {@code null}, we simply return {@code BigDecimal.ZERO}.
    1752     *
    1753     * @param value the {@link String} to convert, may be null.
    1754     * @param scale the number of digits to the right of the decimal point.
    1755     * @param roundingMode a rounding behavior for numerical operations capable of
    1756     *  discarding precision.
    1757     * @return the scaled, with appropriate rounding, {@link BigDecimal}.
    1758     * @since 3.8
    1759     */
    1760    public static BigDecimal toScaledBigDecimal(final String value, final int scale, final RoundingMode roundingMode) {
    1761        if (value == null) {
    1762            return BigDecimal.ZERO;
    1763        }
    1764        return toScaledBigDecimal(
    1765            createBigDecimal(value),
    1766            scale,
    1767            roundingMode
    1768        );
    1769    }
    1770
    1771    /**
    1772     * Convert a {@link String} to a {@code short}, returning
    1773     * {@code zero} if the conversion fails.
    1774     *
    1775     * <p>If the string is {@code null}, {@code zero} is returned.</p>
    1776     *
    1777     * <pre>
    1778     *   NumberUtils.toShort(null) = 0
    1779     *   NumberUtils.toShort("")   = 0
    1780     *   NumberUtils.toShort("1")  = 1
    1781     * </pre>
    1782     *
    1783     * @param str  the string to convert, may be null
    1784     * @return the short represented by the string, or {@code zero} if
    1785     *  conversion fails
    1786     * @since 2.5
    1787     */
    1788    public static short toShort(final String str) {
    1789        return toShort(str, (short) 0);
    1790    }
    1791
    1792    /**
    1793     * Convert a {@link String} to an {@code short}, returning a
    1794     * default value if the conversion fails.
    1795     *
    1796     * <p>If the string is {@code null}, the default value is returned.</p>
    1797     *
    1798     * <pre>
    1799     *   NumberUtils.toShort(null, 1) = 1
    1800     *   NumberUtils.toShort("", 1)   = 1
    1801     *   NumberUtils.toShort("1", 0)  = 1
    1802     * </pre>
    1803     *
    1804     * @param str  the string to convert, may be null
    1805     * @param defaultValue  the default value
    1806     * @return the short represented by the string, or the default if conversion fails
    1807     * @since 2.5
    1808     */
    1809    public static short toShort(final String str, final short defaultValue) {
    1810        if (str == null) {
    1811            return defaultValue;
    1812        }
    1813        try {
    1814            return Short.parseShort(str);
    1815        } catch (final NumberFormatException nfe) {
    1816            return defaultValue;
    1817        }
    1818    }
    1819
    1820    /**
    1821     * Checks if the specified array is neither null nor empty.
    1822     *
    1823     * @param array  the array to check
    1824     * @throws IllegalArgumentException if {@code array} is empty
    1825     * @throws NullPointerException if {@code array} is {@code null}
    1826     */
    1827    private static void validateArray(final Object array) {
    1828        Objects.requireNonNull(array, "array");
    1829        Validate.isTrue(Array.getLength(array) != 0, "Array cannot be empty.");
    1830    }
    1831
    1832    private static boolean withDecimalsParsing(final String str, final int beginIdx) {
    1833        int decimalPoints = 0;
    1834        for (int i = beginIdx; i < str.length(); i++) {
    1835            final char ch = str.charAt(i);
    1836            final boolean isDecimalPoint = ch == '.';
    1837            if (isDecimalPoint) {
    1838                decimalPoints++;
    1839            }
    1840            if (decimalPoints > 1) {
    1841                return false;
    1842            }
    1843            if (!isDecimalPoint && !Character.isDigit(ch)) {
    1844                return false;
    1845            }
    1846        }
    1847        return true;
    1848    }
    1849
    1850    /**
    1851     * {@link NumberUtils} instances should NOT be constructed in standard programming.
    1852     * Instead, the class should be used as {@code NumberUtils.toInt("6");}.
    1853     *
    1854     * <p>This constructor is public to permit tools that require a JavaBean instance
    1855     * to operate.</p>
    1856     *
    1857     * @deprecated TODO Make private in 4.0.
    1858     */
    1859    @Deprecated
    1860    public NumberUtils() {
    1861        // empty
    1862    }
    1863}