Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.lang3.math; import java.lang.reflect.Array; import java.math.BigDecimal; import java.math.BigInteger; import org.apache.commons.lang3.StringUtils; import org.apache.commons.lang3.Validate; /** * <p>Provides extra functionality for Java Number classes.</p> * * @since 2.0 * @version $Id$ */ public class NumberUtils { /** Reusable Long constant for zero. */ public static final Long LONG_ZERO = Long.valueOf(0L); /** Reusable Long constant for one. */ public static final Long LONG_ONE = Long.valueOf(1L); /** Reusable Long constant for minus one. */ public static final Long LONG_MINUS_ONE = Long.valueOf(-1L); /** Reusable Integer constant for zero. */ public static final Integer INTEGER_ZERO = Integer.valueOf(0); /** Reusable Integer constant for one. */ public static final Integer INTEGER_ONE = Integer.valueOf(1); /** Reusable Integer constant for minus one. */ public static final Integer INTEGER_MINUS_ONE = Integer.valueOf(-1); /** Reusable Short constant for zero. */ public static final Short SHORT_ZERO = Short.valueOf((short) 0); /** Reusable Short constant for one. */ public static final Short SHORT_ONE = Short.valueOf((short) 1); /** Reusable Short constant for minus one. */ public static final Short SHORT_MINUS_ONE = Short.valueOf((short) -1); /** Reusable Byte constant for zero. */ public static final Byte BYTE_ZERO = Byte.valueOf((byte) 0); /** Reusable Byte constant for one. */ public static final Byte BYTE_ONE = Byte.valueOf((byte) 1); /** Reusable Byte constant for minus one. */ public static final Byte BYTE_MINUS_ONE = Byte.valueOf((byte) -1); /** Reusable Double constant for zero. */ public static final Double DOUBLE_ZERO = Double.valueOf(0.0d); /** Reusable Double constant for one. */ public static final Double DOUBLE_ONE = Double.valueOf(1.0d); /** Reusable Double constant for minus one. */ public static final Double DOUBLE_MINUS_ONE = Double.valueOf(-1.0d); /** Reusable Float constant for zero. */ public static final Float FLOAT_ZERO = Float.valueOf(0.0f); /** Reusable Float constant for one. */ public static final Float FLOAT_ONE = Float.valueOf(1.0f); /** Reusable Float constant for minus one. */ public static final Float FLOAT_MINUS_ONE = Float.valueOf(-1.0f); /** * <p><code>NumberUtils</code> instances should NOT be constructed in standard programming. * Instead, the class should be used as <code>NumberUtils.toInt("6");</code>.</p> * * <p>This constructor is public to permit tools that require a JavaBean instance * to operate.</p> */ public NumberUtils() { super(); } //----------------------------------------------------------------------- /** * <p>Convert a <code>String</code> to an <code>int</code>, returning * <code>zero</code> if the conversion fails.</p> * * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p> * * <pre> * NumberUtils.toInt(null) = 0 * NumberUtils.toInt("") = 0 * NumberUtils.toInt("1") = 1 * </pre> * * @param str the string to convert, may be null * @return the int represented by the string, or <code>zero</code> if * conversion fails * @since 2.1 */ public static int toInt(final String str) { return toInt(str, 0); } /** * <p>Convert a <code>String</code> to an <code>int</code>, returning a * default value if the conversion fails.</p> * * <p>If the string is <code>null</code>, the default value is returned.</p> * * <pre> * NumberUtils.toInt(null, 1) = 1 * NumberUtils.toInt("", 1) = 1 * NumberUtils.toInt("1", 0) = 1 * </pre> * * @param str the string to convert, may be null * @param defaultValue the default value * @return the int represented by the string, or the default if conversion fails * @since 2.1 */ public static int toInt(final String str, final int defaultValue) { if (str == null) { return defaultValue; } try { return Integer.parseInt(str); } catch (final NumberFormatException nfe) { return defaultValue; } } /** * <p>Convert a <code>String</code> to a <code>long</code>, returning * <code>zero</code> if the conversion fails.</p> * * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p> * * <pre> * NumberUtils.toLong(null) = 0L * NumberUtils.toLong("") = 0L * NumberUtils.toLong("1") = 1L * </pre> * * @param str the string to convert, may be null * @return the long represented by the string, or <code>0</code> if * conversion fails * @since 2.1 */ public static long toLong(final String str) { return toLong(str, 0L); } /** * <p>Convert a <code>String</code> to a <code>long</code>, returning a * default value if the conversion fails.</p> * * <p>If the string is <code>null</code>, the default value is returned.</p> * * <pre> * NumberUtils.toLong(null, 1L) = 1L * NumberUtils.toLong("", 1L) = 1L * NumberUtils.toLong("1", 0L) = 1L * </pre> * * @param str the string to convert, may be null * @param defaultValue the default value * @return the long represented by the string, or the default if conversion fails * @since 2.1 */ public static long toLong(final String str, final long defaultValue) { if (str == null) { return defaultValue; } try { return Long.parseLong(str); } catch (final NumberFormatException nfe) { return defaultValue; } } /** * <p>Convert a <code>String</code> to a <code>float</code>, returning * <code>0.0f</code> if the conversion fails.</p> * * <p>If the string <code>str</code> is <code>null</code>, * <code>0.0f</code> is returned.</p> * * <pre> * NumberUtils.toFloat(null) = 0.0f * NumberUtils.toFloat("") = 0.0f * NumberUtils.toFloat("1.5") = 1.5f * </pre> * * @param str the string to convert, may be <code>null</code> * @return the float represented by the string, or <code>0.0f</code> * if conversion fails * @since 2.1 */ public static float toFloat(final String str) { return toFloat(str, 0.0f); } /** * <p>Convert a <code>String</code> to a <code>float</code>, returning a * default value if the conversion fails.</p> * * <p>If the string <code>str</code> is <code>null</code>, the default * value is returned.</p> * * <pre> * NumberUtils.toFloat(null, 1.1f) = 1.0f * NumberUtils.toFloat("", 1.1f) = 1.1f * NumberUtils.toFloat("1.5", 0.0f) = 1.5f * </pre> * * @param str the string to convert, may be <code>null</code> * @param defaultValue the default value * @return the float represented by the string, or defaultValue * if conversion fails * @since 2.1 */ public static float toFloat(final String str, final float defaultValue) { if (str == null) { return defaultValue; } try { return Float.parseFloat(str); } catch (final NumberFormatException nfe) { return defaultValue; } } /** * <p>Convert a <code>String</code> to a <code>double</code>, returning * <code>0.0d</code> if the conversion fails.</p> * * <p>If the string <code>str</code> is <code>null</code>, * <code>0.0d</code> is returned.</p> * * <pre> * NumberUtils.toDouble(null) = 0.0d * NumberUtils.toDouble("") = 0.0d * NumberUtils.toDouble("1.5") = 1.5d * </pre> * * @param str the string to convert, may be <code>null</code> * @return the double represented by the string, or <code>0.0d</code> * if conversion fails * @since 2.1 */ public static double toDouble(final String str) { return toDouble(str, 0.0d); } /** * <p>Convert a <code>String</code> to a <code>double</code>, returning a * default value if the conversion fails.</p> * * <p>If the string <code>str</code> is <code>null</code>, the default * value is returned.</p> * * <pre> * NumberUtils.toDouble(null, 1.1d) = 1.1d * NumberUtils.toDouble("", 1.1d) = 1.1d * NumberUtils.toDouble("1.5", 0.0d) = 1.5d * </pre> * * @param str the string to convert, may be <code>null</code> * @param defaultValue the default value * @return the double represented by the string, or defaultValue * if conversion fails * @since 2.1 */ public static double toDouble(final String str, final double defaultValue) { if (str == null) { return defaultValue; } try { return Double.parseDouble(str); } catch (final NumberFormatException nfe) { return defaultValue; } } //----------------------------------------------------------------------- /** * <p>Convert a <code>String</code> to a <code>byte</code>, returning * <code>zero</code> if the conversion fails.</p> * * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p> * * <pre> * NumberUtils.toByte(null) = 0 * NumberUtils.toByte("") = 0 * NumberUtils.toByte("1") = 1 * </pre> * * @param str the string to convert, may be null * @return the byte represented by the string, or <code>zero</code> if * conversion fails * @since 2.5 */ public static byte toByte(final String str) { return toByte(str, (byte) 0); } /** * <p>Convert a <code>String</code> to a <code>byte</code>, returning a * default value if the conversion fails.</p> * * <p>If the string is <code>null</code>, the default value is returned.</p> * * <pre> * NumberUtils.toByte(null, 1) = 1 * NumberUtils.toByte("", 1) = 1 * NumberUtils.toByte("1", 0) = 1 * </pre> * * @param str the string to convert, may be null * @param defaultValue the default value * @return the byte represented by the string, or the default if conversion fails * @since 2.5 */ public static byte toByte(final String str, final byte defaultValue) { if (str == null) { return defaultValue; } try { return Byte.parseByte(str); } catch (final NumberFormatException nfe) { return defaultValue; } } /** * <p>Convert a <code>String</code> to a <code>short</code>, returning * <code>zero</code> if the conversion fails.</p> * * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p> * * <pre> * NumberUtils.toShort(null) = 0 * NumberUtils.toShort("") = 0 * NumberUtils.toShort("1") = 1 * </pre> * * @param str the string to convert, may be null * @return the short represented by the string, or <code>zero</code> if * conversion fails * @since 2.5 */ public static short toShort(final String str) { return toShort(str, (short) 0); } /** * <p>Convert a <code>String</code> to an <code>short</code>, returning a * default value if the conversion fails.</p> * * <p>If the string is <code>null</code>, the default value is returned.</p> * * <pre> * NumberUtils.toShort(null, 1) = 1 * NumberUtils.toShort("", 1) = 1 * NumberUtils.toShort("1", 0) = 1 * </pre> * * @param str the string to convert, may be null * @param defaultValue the default value * @return the short represented by the string, or the default if conversion fails * @since 2.5 */ public static short toShort(final String str, final short defaultValue) { if (str == null) { return defaultValue; } try { return Short.parseShort(str); } catch (final NumberFormatException nfe) { return defaultValue; } } //----------------------------------------------------------------------- // must handle Long, Float, Integer, Float, Short, // BigDecimal, BigInteger and Byte // useful methods: // Byte.decode(String) // Byte.valueOf(String,int radix) // Byte.valueOf(String) // Double.valueOf(String) // Float.valueOf(String) // Float.valueOf(String) // Integer.valueOf(String,int radix) // Integer.valueOf(String) // Integer.decode(String) // Integer.getInteger(String) // Integer.getInteger(String,int val) // Integer.getInteger(String,Integer val) // Integer.valueOf(String) // Double.valueOf(String) // new Byte(String) // Long.valueOf(String) // Long.getLong(String) // Long.getLong(String,int) // Long.getLong(String,Integer) // Long.valueOf(String,int) // Long.valueOf(String) // Short.valueOf(String) // Short.decode(String) // Short.valueOf(String,int) // Short.valueOf(String) // new BigDecimal(String) // new BigInteger(String) // new BigInteger(String,int radix) // Possible inputs: // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd // plus minus everything. Prolly more. A lot are not separable. /** * <p>Turns a string value into a java.lang.Number.</p> * * <p>If the string starts with {@code 0x} or {@code -0x} (lower or upper case) or {@code #} or {@code -#}, it * will be interpreted as a hexadecimal Integer - or Long, if the number of digits after the * prefix is more than 8 - or BigInteger if there are more than 16 digits. * </p> * <p>Then, the value is examined for a type qualifier on the end, i.e. one of * <code>'f','F','d','D','l','L'</code>. If it is found, it starts * trying to create successively larger types from the type specified * until one is found that can represent the value.</p> * * <p>If a type specifier is not found, it will check for a decimal point * and then try successively larger types from <code>Integer</code> to * <code>BigInteger</code> and from <code>Float</code> to * <code>BigDecimal</code>.</p> * * <p> * Integral values with a leading {@code 0} will be interpreted as octal; the returned number will * be Integer, Long or BigDecimal as appropriate. * </p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * <p>This method does not trim the input string, i.e., strings with leading * or trailing spaces will generate NumberFormatExceptions.</p> * * @param str String containing a number, may be null * @return Number created from the string (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static Number createNumber(final String str) throws NumberFormatException { if (str == null) { return null; } if (StringUtils.isBlank(str)) { throw new NumberFormatException("A blank string is not a valid number"); } // Need to deal with all possible hex prefixes here final String[] hex_prefixes = { "0x", "0X", "-0x", "-0X", "#", "-#" }; int pfxLen = 0; for (final String pfx : hex_prefixes) { if (str.startsWith(pfx)) { pfxLen += pfx.length(); break; } } if (pfxLen > 0) { // we have a hex number char firstSigDigit = 0; // strip leading zeroes for (int i = pfxLen; i < str.length(); i++) { firstSigDigit = str.charAt(i); if (firstSigDigit == '0') { // count leading zeroes pfxLen++; } else { break; } } final int hexDigits = str.length() - pfxLen; if (hexDigits > 16 || (hexDigits == 16 && firstSigDigit > '7')) { // too many for Long return createBigInteger(str); } if (hexDigits > 8 || (hexDigits == 8 && firstSigDigit > '7')) { // too many for an int return createLong(str); } return createInteger(str); } final char lastChar = str.charAt(str.length() - 1); String mant; String dec; String exp; final int decPos = str.indexOf('.'); final int expPos = str.indexOf('e') + str.indexOf('E') + 1; // assumes both not present // if both e and E are present, this is caught by the checks on expPos (which prevent IOOBE) // and the parsing which will detect if e or E appear in a number due to using the wrong offset int numDecimals = 0; // Check required precision (LANG-693) if (decPos > -1) { // there is a decimal point if (expPos > -1) { // there is an exponent if (expPos < decPos || expPos > str.length()) { // prevents double exponent causing IOOBE throw new NumberFormatException(str + " is not a valid number."); } dec = str.substring(decPos + 1, expPos); } else { dec = str.substring(decPos + 1); } mant = getMantissa(str, decPos); numDecimals = dec.length(); // gets number of digits past the decimal to ensure no loss of precision for floating point numbers. } else { if (expPos > -1) { if (expPos > str.length()) { // prevents double exponent causing IOOBE throw new NumberFormatException(str + " is not a valid number."); } mant = getMantissa(str, expPos); } else { mant = getMantissa(str); } dec = null; } if (!Character.isDigit(lastChar) && lastChar != '.') { if (expPos > -1 && expPos < str.length() - 1) { exp = str.substring(expPos + 1, str.length() - 1); } else { exp = null; } //Requesting a specific type.. final String numeric = str.substring(0, str.length() - 1); final boolean allZeros = isAllZeros(mant) && isAllZeros(exp); switch (lastChar) { case 'l': case 'L': if (dec == null && exp == null && (numeric.charAt(0) == '-' && isDigits(numeric.substring(1)) || isDigits(numeric))) { try { return createLong(numeric); } catch (final NumberFormatException nfe) { // NOPMD // Too big for a long } return createBigInteger(numeric); } throw new NumberFormatException(str + " is not a valid number."); case 'f': case 'F': try { final Float f = NumberUtils.createFloat(numeric); if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) { //If it's too big for a float or the float value = 0 and the string //has non-zeros in it, then float does not have the precision we want return f; } } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } //$FALL-THROUGH$ case 'd': case 'D': try { final Double d = NumberUtils.createDouble(numeric); if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) { return d; } } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } try { return createBigDecimal(numeric); } catch (final NumberFormatException e) { // NOPMD // ignore the bad number } //$FALL-THROUGH$ default: throw new NumberFormatException(str + " is not a valid number."); } } //User doesn't have a preference on the return type, so let's start //small and go from there... if (expPos > -1 && expPos < str.length() - 1) { exp = str.substring(expPos + 1, str.length()); } else { exp = null; } if (dec == null && exp == null) { // no decimal point and no exponent //Must be an Integer, Long, Biginteger try { return createInteger(str); } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } try { return createLong(str); } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } return createBigInteger(str); } //Must be a Float, Double, BigDecimal final boolean allZeros = isAllZeros(mant) && isAllZeros(exp); try { if (numDecimals <= 7) {// If number has 7 or fewer digits past the decimal point then make it a float final Float f = createFloat(str); if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) { return f; } } } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } try { if (numDecimals <= 16) {// If number has between 8 and 16 digits past the decimal point then make it a double final Double d = createDouble(str); if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) { return d; } } } catch (final NumberFormatException nfe) { // NOPMD // ignore the bad number } return createBigDecimal(str); } /** * <p>Utility method for {@link #createNumber(java.lang.String)}.</p> * * <p>Returns mantissa of the given number.</p> * * @param str the string representation of the number * @return mantissa of the given number */ private static String getMantissa(final String str) { return getMantissa(str, str.length()); } /** * <p>Utility method for {@link #createNumber(java.lang.String)}.</p> * * <p>Returns mantissa of the given number.</p> * * @param str the string representation of the number * @param stopPos the position of the exponent or decimal point * @return mantissa of the given number */ private static String getMantissa(final String str, final int stopPos) { final char firstChar = str.charAt(0); final boolean hasSign = (firstChar == '-' || firstChar == '+'); return hasSign ? str.substring(1, stopPos) : str.substring(0, stopPos); } /** * <p>Utility method for {@link #createNumber(java.lang.String)}.</p> * * <p>Returns <code>true</code> if s is <code>null</code>.</p> * * @param str the String to check * @return if it is all zeros or <code>null</code> */ private static boolean isAllZeros(final String str) { if (str == null) { return true; } for (int i = str.length() - 1; i >= 0; i--) { if (str.charAt(i) != '0') { return false; } } return str.length() > 0; } //----------------------------------------------------------------------- /** * <p>Convert a <code>String</code> to a <code>Float</code>.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>Float</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static Float createFloat(final String str) { if (str == null) { return null; } return Float.valueOf(str); } /** * <p>Convert a <code>String</code> to a <code>Double</code>.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>Double</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static Double createDouble(final String str) { if (str == null) { return null; } return Double.valueOf(str); } /** * <p>Convert a <code>String</code> to a <code>Integer</code>, handling * hex (0xhhhh) and octal (0dddd) notations. * N.B. a leading zero means octal; spaces are not trimmed.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>Integer</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static Integer createInteger(final String str) { if (str == null) { return null; } // decode() handles 0xAABD and 0777 (hex and octal) as well. return Integer.decode(str); } /** * <p>Convert a <code>String</code> to a <code>Long</code>; * since 3.1 it handles hex (0Xhhhh) and octal (0ddd) notations. * N.B. a leading zero means octal; spaces are not trimmed.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>Long</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static Long createLong(final String str) { if (str == null) { return null; } return Long.decode(str); } /** * <p>Convert a <code>String</code> to a <code>BigInteger</code>; * since 3.2 it handles hex (0x or #) and octal (0) notations.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>BigInteger</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static BigInteger createBigInteger(final String str) { if (str == null) { return null; } int pos = 0; // offset within string int radix = 10; boolean negate = false; // need to negate later? if (str.startsWith("-")) { negate = true; pos = 1; } if (str.startsWith("0x", pos) || str.startsWith("0X", pos)) { // hex radix = 16; pos += 2; } else if (str.startsWith("#", pos)) { // alternative hex (allowed by Long/Integer) radix = 16; pos++; } else if (str.startsWith("0", pos) && str.length() > pos + 1) { // octal; so long as there are additional digits radix = 8; pos++; } // default is to treat as decimal final BigInteger value = new BigInteger(str.substring(pos), radix); return negate ? value.negate() : value; } /** * <p>Convert a <code>String</code> to a <code>BigDecimal</code>.</p> * * <p>Returns <code>null</code> if the string is <code>null</code>.</p> * * @param str a <code>String</code> to convert, may be null * @return converted <code>BigDecimal</code> (or null if the input is null) * @throws NumberFormatException if the value cannot be converted */ public static BigDecimal createBigDecimal(final String str) { if (str == null) { return null; } // handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException if (StringUtils.isBlank(str)) { throw new NumberFormatException("A blank string is not a valid number"); } if (str.trim().startsWith("--")) { // this is protection for poorness in java.lang.BigDecimal. // it accepts this as a legal value, but it does not appear // to be in specification of class. OS X Java parses it to // a wrong value. throw new NumberFormatException(str + " is not a valid number."); } return new BigDecimal(str); } // Min in array //-------------------------------------------------------------------- /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from min(long[]) to min(long...) */ public static long min(final long... array) { // Validates input validateArray(array); // Finds and returns min long min = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] < min) { min = array[i]; } } return min; } /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from min(int[]) to min(int...) */ public static int min(final int... array) { // Validates input validateArray(array); // Finds and returns min int min = array[0]; for (int j = 1; j < array.length; j++) { if (array[j] < min) { min = array[j]; } } return min; } /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from min(short[]) to min(short...) */ public static short min(final short... array) { // Validates input validateArray(array); // Finds and returns min short min = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] < min) { min = array[i]; } } return min; } /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from min(byte[]) to min(byte...) */ public static byte min(final byte... array) { // Validates input validateArray(array); // Finds and returns min byte min = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] < min) { min = array[i]; } } return min; } /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this method that handles NaN differently * @since 3.4 Changed signature from min(double[]) to min(double...) */ public static double min(final double... array) { // Validates input validateArray(array); // Finds and returns min double min = array[0]; for (int i = 1; i < array.length; i++) { if (Double.isNaN(array[i])) { return Double.NaN; } if (array[i] < min) { min = array[i]; } } return min; } /** * <p>Returns the minimum value in an array.</p> * * @param array an array, must not be null or empty * @return the minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this method that handles NaN differently * @since 3.4 Changed signature from min(float[]) to min(float...) */ public static float min(final float... array) { // Validates input validateArray(array); // Finds and returns min float min = array[0]; for (int i = 1; i < array.length; i++) { if (Float.isNaN(array[i])) { return Float.NaN; } if (array[i] < min) { min = array[i]; } } return min; } // Max in array //-------------------------------------------------------------------- /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from max(long[]) to max(long...) */ public static long max(final long... array) { // Validates input validateArray(array); // Finds and returns max long max = array[0]; for (int j = 1; j < array.length; j++) { if (array[j] > max) { max = array[j]; } } return max; } /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from max(int[]) to max(int...) */ public static int max(final int... array) { // Validates input validateArray(array); // Finds and returns max int max = array[0]; for (int j = 1; j < array.length; j++) { if (array[j] > max) { max = array[j]; } } return max; } /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from max(short[]) to max(short...) */ public static short max(final short... array) { // Validates input validateArray(array); // Finds and returns max short max = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] > max) { max = array[i]; } } return max; } /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @since 3.4 Changed signature from max(byte[]) to max(byte...) */ public static byte max(final byte... array) { // Validates input validateArray(array); // Finds and returns max byte max = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] > max) { max = array[i]; } } return max; } /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @see IEEE754rUtils#max(double[]) IEEE754rUtils for a version of this method that handles NaN differently * @since 3.4 Changed signature from max(double[]) to max(double...) */ public static double max(final double... array) { // Validates input validateArray(array); // Finds and returns max double max = array[0]; for (int j = 1; j < array.length; j++) { if (Double.isNaN(array[j])) { return Double.NaN; } if (array[j] > max) { max = array[j]; } } return max; } /** * <p>Returns the maximum value in an array.</p> * * @param array an array, must not be null or empty * @return the maximum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this method that handles NaN differently * @since 3.4 Changed signature from max(float[]) to max(float...) */ public static float max(final float... array) { // Validates input validateArray(array); // Finds and returns max float max = array[0]; for (int j = 1; j < array.length; j++) { if (Float.isNaN(array[j])) { return Float.NaN; } if (array[j] > max) { max = array[j]; } } return max; } /** * Checks if the specified array is neither null nor empty. * * @param array the array to check * @throws IllegalArgumentException if {@code array} is either {@code null} or empty */ private static void validateArray(final Object array) { if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } Validate.isTrue(Array.getLength(array) != 0, "Array cannot be empty."); } // 3 param min //----------------------------------------------------------------------- /** * <p>Gets the minimum of three <code>long</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values */ public static long min(long a, final long b, final long c) { if (b < a) { a = b; } if (c < a) { a = c; } return a; } /** * <p>Gets the minimum of three <code>int</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values */ public static int min(int a, final int b, final int c) { if (b < a) { a = b; } if (c < a) { a = c; } return a; } /** * <p>Gets the minimum of three <code>short</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values */ public static short min(short a, final short b, final short c) { if (b < a) { a = b; } if (c < a) { a = c; } return a; } /** * <p>Gets the minimum of three <code>byte</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values */ public static byte min(byte a, final byte b, final byte c) { if (b < a) { a = b; } if (c < a) { a = c; } return a; } /** * <p>Gets the minimum of three <code>double</code> values.</p> * * <p>If any value is <code>NaN</code>, <code>NaN</code> is * returned. Infinity is handled.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values * @see IEEE754rUtils#min(double, double, double) for a version of this method that handles NaN differently */ public static double min(final double a, final double b, final double c) { return Math.min(Math.min(a, b), c); } /** * <p>Gets the minimum of three <code>float</code> values.</p> * * <p>If any value is <code>NaN</code>, <code>NaN</code> is * returned. Infinity is handled.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the smallest of the values * @see IEEE754rUtils#min(float, float, float) for a version of this method that handles NaN differently */ public static float min(final float a, final float b, final float c) { return Math.min(Math.min(a, b), c); } // 3 param max //----------------------------------------------------------------------- /** * <p>Gets the maximum of three <code>long</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values */ public static long max(long a, final long b, final long c) { if (b > a) { a = b; } if (c > a) { a = c; } return a; } /** * <p>Gets the maximum of three <code>int</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values */ public static int max(int a, final int b, final int c) { if (b > a) { a = b; } if (c > a) { a = c; } return a; } /** * <p>Gets the maximum of three <code>short</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values */ public static short max(short a, final short b, final short c) { if (b > a) { a = b; } if (c > a) { a = c; } return a; } /** * <p>Gets the maximum of three <code>byte</code> values.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values */ public static byte max(byte a, final byte b, final byte c) { if (b > a) { a = b; } if (c > a) { a = c; } return a; } /** * <p>Gets the maximum of three <code>double</code> values.</p> * * <p>If any value is <code>NaN</code>, <code>NaN</code> is * returned. Infinity is handled.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values * @see IEEE754rUtils#max(double, double, double) for a version of this method that handles NaN differently */ public static double max(final double a, final double b, final double c) { return Math.max(Math.max(a, b), c); } /** * <p>Gets the maximum of three <code>float</code> values.</p> * * <p>If any value is <code>NaN</code>, <code>NaN</code> is * returned. Infinity is handled.</p> * * @param a value 1 * @param b value 2 * @param c value 3 * @return the largest of the values * @see IEEE754rUtils#max(float, float, float) for a version of this method that handles NaN differently */ public static float max(final float a, final float b, final float c) { return Math.max(Math.max(a, b), c); } //----------------------------------------------------------------------- /** * <p>Checks whether the <code>String</code> contains only * digit characters.</p> * * <p><code>Null</code> and empty String will return * <code>false</code>.</p> * * @param str the <code>String</code> to check * @return <code>true</code> if str contains only Unicode numeric */ public static boolean isDigits(final String str) { if (StringUtils.isEmpty(str)) { return false; } for (int i = 0; i < str.length(); i++) { if (!Character.isDigit(str.charAt(i))) { return false; } } return true; } /** * <p>Checks whether the String a valid Java number.</p> * * <p>Valid numbers include hexadecimal marked with the <code>0x</code> or * <code>0X</code> qualifier, octal numbers, scientific notation and numbers * marked with a type qualifier (e.g. 123L).</p> * * <p>Non-hexadecimal strings beginning with a leading zero are * treated as octal values. Thus the string <code>09</code> will return * <code>false</code>, since <code>9</code> is not a valid octal value. * However, numbers beginning with {@code 0.} are treated as decimal.</p> * * <p><code>null</code> and empty/blank {@code String} will return * <code>false</code>.</p> * * @param str the <code>String</code> to check * @return <code>true</code> if the string is a correctly formatted number * @since 3.3 the code supports hex {@code 0Xhhh} and octal {@code 0ddd} validation */ public static boolean isNumber(final String str) { if (StringUtils.isEmpty(str)) { return false; } final char[] chars = str.toCharArray(); int sz = chars.length; boolean hasExp = false; boolean hasDecPoint = false; boolean allowSigns = false; boolean foundDigit = false; // deal with any possible sign up front final int start = (chars[0] == '-') ? 1 : 0; if (sz > start + 1 && chars[start] == '0') { // leading 0 if ((chars[start + 1] == 'x') || (chars[start + 1] == 'X')) { // leading 0x/0X int i = start + 2; if (i == sz) { return false; // str == "0x" } // checking hex (it can't be anything else) for (; i < chars.length; i++) { if ((chars[i] < '0' || chars[i] > '9') && (chars[i] < 'a' || chars[i] > 'f') && (chars[i] < 'A' || chars[i] > 'F')) { return false; } } return true; } else if (Character.isDigit(chars[start + 1])) { // leading 0, but not hex, must be octal int i = start + 1; for (; i < chars.length; i++) { if (chars[i] < '0' || chars[i] > '7') { return false; } } return true; } } sz--; // don't want to loop to the last char, check it afterwords // for type qualifiers int i = start; // loop to the next to last char or to the last char if we need another digit to // make a valid number (e.g. chars[0..5] = "1234E") while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) { if (chars[i] >= '0' && chars[i] <= '9') { foundDigit = true; allowSigns = false; } else if (chars[i] == '.') { if (hasDecPoint || hasExp) { // two decimal points or dec in exponent return false; } hasDecPoint = true; } else if (chars[i] == 'e' || chars[i] == 'E') { // we've already taken care of hex. if (hasExp) { // two E's return false; } if (!foundDigit) { return false; } hasExp = true; allowSigns = true; } else if (chars[i] == '+' || chars[i] == '-') { if (!allowSigns) { return false; } allowSigns = false; foundDigit = false; // we need a digit after the E } else { return false; } i++; } if (i < chars.length) { if (chars[i] >= '0' && chars[i] <= '9') { // no type qualifier, OK return true; } if (chars[i] == 'e' || chars[i] == 'E') { // can't have an E at the last byte return false; } if (chars[i] == '.') { if (hasDecPoint || hasExp) { // two decimal points or dec in exponent return false; } // single trailing decimal point after non-exponent is ok return foundDigit; } if (!allowSigns && (chars[i] == 'd' || chars[i] == 'D' || chars[i] == 'f' || chars[i] == 'F')) { return foundDigit; } if (chars[i] == 'l' || chars[i] == 'L') { // not allowing L with an exponent or decimal point return foundDigit && !hasExp && !hasDecPoint; } // last character is illegal return false; } // allowSigns is true iff the val ends in 'E' // found digit it to make sure weird stuff like '.' and '1E-' doesn't pass return !allowSigns && foundDigit; } /** * <p>Checks whether the given String is a parsable number.</p> * * <p>Parsable numbers include those Strings understood by {@link Integer#parseInt(String)}, * {@link Long#parseLong(String)}, {@link Float#parseFloat(String)} or * {@link Double#parseDouble(String)}. This method can be used instead of catching {@link java.text.ParseException} * when calling one of those methods.</p> * * <p>Hexadecimal and scientific notations are <strong>not</strong> considered parsable. * See {@link #isNumber(String)} on those cases.</p> * * <p>{@code Null} and empty String will return <code>false</code>.</p> * * @param str the String to check. * @return {@code true} if the string is a parsable number. * @since 3.4 */ public static boolean isParsable(final String str) { if (StringUtils.endsWith(str, ".")) { return false; } if (StringUtils.startsWith(str, "-")) { return isDigits(StringUtils.replaceOnce(str.substring(1), ".", StringUtils.EMPTY)); } else { return isDigits(StringUtils.replaceOnce(str, ".", StringUtils.EMPTY)); } } /** * <p>Compares two {@code int} values numerically. This is the same functionality as provided in Java 7.</p> * * @param x the first {@code int} to compare * @param y the second {@code int} to compare * @return the value {@code 0} if {@code x == y}; * a value less than {@code 0} if {@code x < y}; and * a value greater than {@code 0} if {@code x > y} * @since 3.4 */ public static int compare(int x, int y) { if (x == y) { return 0; } if (x < y) { return -1; } else { return 1; } } /** * <p>Compares to {@code long} values numerically. This is the same functionality as provided in Java 7.</p> * * @param x the first {@code long} to compare * @param y the second {@code long} to compare * @return the value {@code 0} if {@code x == y}; * a value less than {@code 0} if {@code x < y}; and * a value greater than {@code 0} if {@code x > y} * @since 3.4 */ public static int compare(long x, long y) { if (x == y) { return 0; } if (x < y) { return -1; } else { return 1; } } /** * <p>Compares to {@code short} values numerically. This is the same functionality as provided in Java 7.</p> * * @param x the first {@code short} to compare * @param y the second {@code short} to compare * @return the value {@code 0} if {@code x == y}; * a value less than {@code 0} if {@code x < y}; and * a value greater than {@code 0} if {@code x > y} * @since 3.4 */ public static int compare(short x, short y) { if (x == y) { return 0; } if (x < y) { return -1; } else { return 1; } } /** * <p>Compares two {@code byte} values numerically. This is the same functionality as provided in Java 7.</p> * * @param x the first {@code byte} to compare * @param y the second {@code byte} to compare * @return the value {@code 0} if {@code x == y}; * a value less than {@code 0} if {@code x < y}; and * a value greater than {@code 0} if {@code x > y} * @since 3.4 */ public static int compare(byte x, byte y) { return x - y; } }