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.lang.math; import java.math.BigDecimal; import java.math.BigInteger; import org.apache.commons.lang.StringUtils; /** * <p>Provides extra functionality for Java Number classes.</p> * * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a> * @author Stephen Colebourne * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a> * @author Eric Pugh * @author Phil Steitz * @author Matthew Hawthorne * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a> * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a> * @since 2.0 * @version $Id$ */ public class NumberUtils { /** Reusable Long constant for zero. */ public static final Long LONG_ZERO = new Long(0L); /** Reusable Long constant for one. */ public static final Long LONG_ONE = new Long(1L); /** Reusable Long constant for minus one. */ public static final Long LONG_MINUS_ONE = new Long(-1L); /** Reusable Integer constant for zero. */ public static final Integer INTEGER_ZERO = new Integer(0); /** Reusable Integer constant for one. */ public static final Integer INTEGER_ONE = new Integer(1); /** Reusable Integer constant for minus one. */ public static final Integer INTEGER_MINUS_ONE = new Integer(-1); /** Reusable Short constant for zero. */ public static final Short SHORT_ZERO = new Short((short) 0); /** Reusable Short constant for one. */ public static final Short SHORT_ONE = new Short((short) 1); /** Reusable Short constant for minus one. */ public static final Short SHORT_MINUS_ONE = new Short((short) -1); /** Reusable Byte constant for zero. */ public static final Byte BYTE_ZERO = new Byte((byte) 0); /** Reusable Byte constant for one. */ public static final Byte BYTE_ONE = new Byte((byte) 1); /** Reusable Byte constant for minus one. */ public static final Byte BYTE_MINUS_ONE = new Byte((byte) -1); /** Reusable Double constant for zero. */ public static final Double DOUBLE_ZERO = new Double(0.0d); /** Reusable Double constant for one. */ public static final Double DOUBLE_ONE = new Double(1.0d); /** Reusable Double constant for minus one. */ public static final Double DOUBLE_MINUS_ONE = new Double(-1.0d); /** Reusable Float constant for zero. */ public static final Float FLOAT_ZERO = new Float(0.0f); /** Reusable Float constant for one. */ public static final Float FLOAT_ONE = new Float(1.0f); /** Reusable Float constant for minus one. */ public static final Float FLOAT_MINUS_ONE = new Float(-1.0f); /** * <p><code>NumberUtils</code> instances should NOT be constructed in standard programming. * Instead, the class should be used as <code>NumberUtils.stringToInt("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.stringToInt(null) = 0 * NumberUtils.stringToInt("") = 0 * NumberUtils.stringToInt("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 * @deprecated Use {@link #toInt(String)} * This method will be removed in Commons Lang 3.0 */ public static int stringToInt(String str) { return toInt(str); } /** * <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(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.stringToInt(null, 1) = 1 * NumberUtils.stringToInt("", 1) = 1 * NumberUtils.stringToInt("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 * @deprecated Use {@link #toInt(String, int)} * This method will be removed in Commons Lang 3.0 */ public static int stringToInt(String str, int defaultValue) { return toInt(str, defaultValue); } /** * <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(String str, int defaultValue) { if (str == null) { return defaultValue; } try { return Integer.parseInt(str); } catch (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(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(String str, long defaultValue) { if (str == null) { return defaultValue; } try { return Long.parseLong(str); } catch (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(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(String str, float defaultValue) { if (str == null) { return defaultValue; } try { return Float.parseFloat(str); } catch (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(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(String str, double defaultValue) { if (str == null) { return defaultValue; } try { return Double.parseDouble(str); } catch (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) // new Float(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) // new Integer(String) // new Double(String) // new Byte(String) // new Long(String) // Long.getLong(String) // Long.getLong(String,int) // Long.getLong(String,Integer) // Long.valueOf(String,int) // Long.valueOf(String) // new Short(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>First, the value is examined for a type qualifier on the end * (<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>If the string starts with <code>0x</code> or <code>-0x</code>, it * will be interpreted as a hexadecimal integer. Values with leading * <code>0</code>'s will not be interpreted as octal.</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 * @throws NumberFormatException if the value cannot be converted */ public static Number createNumber(String str) throws NumberFormatException { if (str == null) { return null; } if (StringUtils.isBlank(str)) { throw new NumberFormatException("A blank string is not a valid number"); } if (str.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. return null; } if (str.startsWith("0x") || str.startsWith("-0x")) { return createInteger(str); } char lastChar = str.charAt(str.length() - 1); String mant; String dec; String exp; int decPos = str.indexOf('.'); int expPos = str.indexOf('e') + str.indexOf('E') + 1; if (decPos > -1) { if (expPos > -1) { if (expPos < decPos) { throw new NumberFormatException(str + " is not a valid number."); } dec = str.substring(decPos + 1, expPos); } else { dec = str.substring(decPos + 1); } mant = str.substring(0, decPos); } else { if (expPos > -1) { mant = str.substring(0, expPos); } else { mant = str; } dec = null; } if (!Character.isDigit(lastChar)) { if (expPos > -1 && expPos < str.length() - 1) { exp = str.substring(expPos + 1, str.length() - 1); } else { exp = null; } //Requesting a specific type.. String numeric = str.substring(0, str.length() - 1); 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 (NumberFormatException nfe) { //Too big for a long } return createBigInteger(numeric); } throw new NumberFormatException(str + " is not a valid number."); case 'f': case 'F': try { 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 (NumberFormatException nfe) { // ignore the bad number } //Fall through case 'd': case 'D': try { Double d = NumberUtils.createDouble(numeric); if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) { return d; } } catch (NumberFormatException nfe) { // ignore the bad number } try { return createBigDecimal(numeric); } catch (NumberFormatException e) { // ignore the bad number } //Fall through default: throw new NumberFormatException(str + " is not a valid number."); } } else { //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) { //Must be an int,long,bigint try { return createInteger(str); } catch (NumberFormatException nfe) { // ignore the bad number } try { return createLong(str); } catch (NumberFormatException nfe) { // ignore the bad number } return createBigInteger(str); } else { //Must be a float,double,BigDec boolean allZeros = isAllZeros(mant) && isAllZeros(exp); try { Float f = createFloat(str); if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) { return f; } } catch (NumberFormatException nfe) { // ignore the bad number } try { Double d = createDouble(str); if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) { return d; } } catch (NumberFormatException nfe) { // ignore the bad number } return createBigDecimal(str); } } } /** * <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(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> * @throws NumberFormatException if the value cannot be converted */ public static Float createFloat(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> * @throws NumberFormatException if the value cannot be converted */ public static Double createDouble(String str) { if (str == null) { return null; } return Double.valueOf(str); } /** * <p>Convert a <code>String</code> to a <code>Integer</code>, handling * hex and octal 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>Integer</code> * @throws NumberFormatException if the value cannot be converted */ public static Integer createInteger(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>.</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> * @throws NumberFormatException if the value cannot be converted */ public static Long createLong(String str) { if (str == null) { return null; } return Long.valueOf(str); } /** * <p>Convert a <code>String</code> to a <code>BigInteger</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>BigInteger</code> * @throws NumberFormatException if the value cannot be converted */ public static BigInteger createBigInteger(String str) { if (str == null) { return null; } return new BigInteger(str); } /** * <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> * @throws NumberFormatException if the value cannot be converted */ public static BigDecimal createBigDecimal(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"); } return new BigDecimal(str); } // Equals in array //-------------------------------------------------------------------- /** * <p>Whether the contents of two byte[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(byte[] array1, byte[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (array1[i] != array2[i]) { return false; } } return true; } /** * <p>Whether the contents of two short[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(short[] array1, short[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (array1[i] != array2[i]) { return false; } } return true; } /** * <p>Whether the contents of two int[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(int[] array1, int[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (array1[i] != array2[i]) { return false; } } return true; } /** * <p>Whether the contents of two long[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(long[] array1, long[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (array1[i] != array2[i]) { return false; } } return true; } /** * <p>Whether the contents of two float[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(float[] array1, float[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (compare(array1[i], array2[i]) != 0) { return false; } } return true; } /** * <p>Whether the contents of two double[] arrays are equal.</p> * * @param array1 first array to compare * @param array2 second array to compare * @return whether the two arrays are equal */ public static boolean equals(double[] array1, double[] array2) { if (array1 == array2) { return true; } if (array1 == null || array2 == null) { return false; } if (array1.length != array2.length) { return false; } for (int i = 0; i < array1.length; i++) { if (compare(array1[i], array2[i]) != 0) { return false; } } return true; } // 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 */ public static long min(long[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 */ public static int min(int[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 */ public static short min(short[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 */ public static byte min(byte[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 */ public static double min(double[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // Finds and returns min double 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 */ public static float min(float[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // Finds and returns min float min = array[0]; for (int i = 1; i < array.length; i++) { 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static long max(long[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static int max(int[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static short max(short[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static byte max(byte[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static double max(double[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // Finds and returns max double 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 minimum value in the array * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty */ public static float max(float[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array cannot be empty."); } // Finds and returns max float max = array[0]; for (int j = 1; j < array.length; j++) { if (array[j] > max) { max = array[j]; } } return max; } // 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, long b, 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, int b, 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, short b, 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, byte b, 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 */ public static double min(double a, double b, 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 */ public static float min(float a, float b, 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, long b, 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, int b, 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, short b, 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, byte b, 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 */ public static double max(double a, double b, 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 */ public static float max(float a, float b, float c) { return Math.max(Math.max(a, b), c); } //----------------------------------------------------------------------- /** * <p>Compares two <code>doubles</code> for order.</p> * * <p>This method is more comprehensive than the standard Java greater * than, less than and equals operators.</p> * <ul> * <li>It returns <code>-1</code> if the first value is less than the second.</li> * <li>It returns <code>+1</code> if the first value is greater than the second.</li> * <li>It returns <code>0</code> if the values are equal.</li> * </ul> * * <p> * The ordering is as follows, largest to smallest: * <ul> * <li>NaN * <li>Positive infinity * <li>Maximum double * <li>Normal positive numbers * <li>+0.0 * <li>-0.0 * <li>Normal negative numbers * <li>Minimum double (<code>-Double.MAX_VALUE</code>) * <li>Negative infinity * </ul> * </p> * * <p>Comparing <code>NaN</code> with <code>NaN</code> will * return <code>0</code>.</p> * * @param lhs the first <code>double</code> * @param rhs the second <code>double</code> * @return <code>-1</code> if lhs is less, <code>+1</code> if greater, * <code>0</code> if equal to rhs */ public static int compare(double lhs, double rhs) { if (lhs < rhs) { return -1; } if (lhs > rhs) { return +1; } // Need to compare bits to handle 0.0 == -0.0 being true // compare should put -0.0 < +0.0 // Two NaNs are also == for compare purposes // where NaN == NaN is false long lhsBits = Double.doubleToLongBits(lhs); long rhsBits = Double.doubleToLongBits(rhs); if (lhsBits == rhsBits) { return 0; } // Something exotic! A comparison to NaN or 0.0 vs -0.0 // Fortunately NaN's long is > than everything else // Also negzeros bits < poszero // NAN: 9221120237041090560 // MAX: 9218868437227405311 // NEGZERO: -9223372036854775808 if (lhsBits < rhsBits) { return -1; } else { return +1; } } /** * <p>Compares two floats for order.</p> * * <p>This method is more comprehensive than the standard Java greater than, * less than and equals operators.</p> * <ul> * <li>It returns <code>-1</code> if the first value is less than the second. * <li>It returns <code>+1</code> if the first value is greater than the second. * <li>It returns <code>0</code> if the values are equal. * </ul> * * <p> The ordering is as follows, largest to smallest: * <ul> * <li>NaN * <li>Positive infinity * <li>Maximum float * <li>Normal positive numbers * <li>+0.0 * <li>-0.0 * <li>Normal negative numbers * <li>Minimum float (<code>-Float.MAX_VALUE</code>) * <li>Negative infinity * </ul> * * <p>Comparing <code>NaN</code> with <code>NaN</code> will return * <code>0</code>.</p> * * @param lhs the first <code>float</code> * @param rhs the second <code>float</code> * @return <code>-1</code> if lhs is less, <code>+1</code> if greater, * <code>0</code> if equal to rhs */ public static int compare(float lhs, float rhs) { if (lhs < rhs) { return -1; } if (lhs > rhs) { return +1; } //Need to compare bits to handle 0.0 == -0.0 being true // compare should put -0.0 < +0.0 // Two NaNs are also == for compare purposes // where NaN == NaN is false int lhsBits = Float.floatToIntBits(lhs); int rhsBits = Float.floatToIntBits(rhs); if (lhsBits == rhsBits) { return 0; } //Something exotic! A comparison to NaN or 0.0 vs -0.0 //Fortunately NaN's int is > than everything else //Also negzeros bits < poszero //NAN: 2143289344 //MAX: 2139095039 //NEGZERO: -2147483648 if (lhsBits < rhsBits) { return -1; } else { return +1; } } //----------------------------------------------------------------------- /** * <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(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> * qualifier, scientific notation and numbers marked with a type * qualifier (e.g. 123L).</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 the string is a correctly formatted number */ public static boolean isNumber(String str) { if (StringUtils.isEmpty(str)) { return false; } 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 int start = (chars[0] == '-') ? 1 : 0; if (sz > start + 1) { if (chars[start] == '0' && chars[start + 1] == 'x') { 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; } } 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 (!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 return foundDigit && !hasExp; } // 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; } }