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; import org.apache.commons.lang.math.NumberUtils; /** * <p>Operations on boolean primitives and Boolean objects.</p> * * <p>This class tries to handle <code>null</code> input gracefully. * An exception will not be thrown for a <code>null</code> input. * Each method documents its behaviour in more detail.</p> * * @author Stephen Colebourne * @author Matthew Hawthorne * @author Gary Gregory * @since 2.0 * @version $Id$ */ public class BooleanUtils { /** * <p><code>BooleanUtils</code> instances should NOT be constructed in standard programming. * Instead, the class should be used as <code>BooleanUtils.toBooleanObject(true);</code>.</p> * * <p>This constructor is public to permit tools that require a JavaBean instance * to operate.</p> */ public BooleanUtils() { super(); } // Boolean utilities //-------------------------------------------------------------------------- /** * <p>Negates the specified boolean.</p> * * <p>If <code>null</code> is passed in, <code>null</code> will be returned.</p> * * <pre> * BooleanUtils.negate(Boolean.TRUE) = Boolean.FALSE; * BooleanUtils.negate(Boolean.FALSE) = Boolean.TRUE; * BooleanUtils.negate(null) = null; * </pre> * * @param bool the Boolean to negate, may be null * @return the negated Boolean, or <code>null</code> if <code>null</code> input */ public static Boolean negate(Boolean bool) { if (bool == null) { return null; } return (bool.booleanValue() ? Boolean.FALSE : Boolean.TRUE); } // boolean Boolean methods //----------------------------------------------------------------------- /** * <p>Checks if a <code>Boolean</code> value is <code>true</code>, * handling <code>null</code> by returning <code>false</code>.</p> * * <pre> * BooleanUtils.isTrue(Boolean.TRUE) = true * BooleanUtils.isTrue(Boolean.FALSE) = false * BooleanUtils.isTrue(null) = false * </pre> * * @param bool the boolean to check, null returns <code>false</code> * @return <code>true</code> only if the input is non-null and true * @since 2.1 */ public static boolean isTrue(Boolean bool) { if (bool == null) { return false; } return bool.booleanValue() ? true : false; } /** * <p>Checks if a <code>Boolean</code> value is <i>not</i> <code>true</code>, * handling <code>null</code> by returning <code>true</code>.</p> * * <pre> * BooleanUtils.isNotTrue(Boolean.TRUE) = false * BooleanUtils.isNotTrue(Boolean.FALSE) = true * BooleanUtils.isNotTrue(null) = true * </pre> * * @param bool the boolean to check, null returns <code>true</code> * @return <code>true</code> if the input is null or false * @since 2.3 */ public static boolean isNotTrue(Boolean bool) { return !isTrue(bool); } /** * <p>Checks if a <code>Boolean</code> value is <code>false</code>, * handling <code>null</code> by returning <code>false</code>.</p> * * <pre> * BooleanUtils.isFalse(Boolean.TRUE) = false * BooleanUtils.isFalse(Boolean.FALSE) = true * BooleanUtils.isFalse(null) = false * </pre> * * @param bool the boolean to check, null returns <code>false</code> * @return <code>true</code> only if the input is non-null and false * @since 2.1 */ public static boolean isFalse(Boolean bool) { if (bool == null) { return false; } return bool.booleanValue() ? false : true; } /** * <p>Checks if a <code>Boolean</code> value is <i>not</i> <code>false</code>, * handling <code>null</code> by returning <code>true</code>.</p> * * <pre> * BooleanUtils.isNotFalse(Boolean.TRUE) = true * BooleanUtils.isNotFalse(Boolean.FALSE) = false * BooleanUtils.isNotFalse(null) = true * </pre> * * @param bool the boolean to check, null returns <code>true</code> * @return <code>true</code> if the input is null or true * @since 2.3 */ public static boolean isNotFalse(Boolean bool) { return !isFalse(bool); } //----------------------------------------------------------------------- /** * <p>Boolean factory that avoids creating new Boolean objecs all the time.</p> * * <p>This method was added to JDK1.4 but is available here for earlier JDKs.</p> * * <pre> * BooleanUtils.toBooleanObject(false) = Boolean.FALSE * BooleanUtils.toBooleanObject(true) = Boolean.TRUE * </pre> * * @param bool the boolean to convert * @return Boolean.TRUE or Boolean.FALSE as appropriate */ public static Boolean toBooleanObject(boolean bool) { return bool ? Boolean.TRUE : Boolean.FALSE; } /** * <p>Converts a Boolean to a boolean handling <code>null</code> * by returning <code>false</code>.</p> * * <pre> * BooleanUtils.toBoolean(Boolean.TRUE) = true * BooleanUtils.toBoolean(Boolean.FALSE) = false * BooleanUtils.toBoolean(null) = false * </pre> * * @param bool the boolean to convert * @return <code>true</code> or <code>false</code>, * <code>null</code> returns <code>false</code> */ public static boolean toBoolean(Boolean bool) { if (bool == null) { return false; } return bool.booleanValue() ? true : false; } /** * <p>Converts a Boolean to a boolean handling <code>null</code>.</p> * * <pre> * BooleanUtils.toBooleanDefaultIfNull(Boolean.TRUE, false) = true * BooleanUtils.toBooleanDefaultIfNull(Boolean.FALSE, true) = false * BooleanUtils.toBooleanDefaultIfNull(null, true) = true * </pre> * * @param bool the boolean to convert * @param valueIfNull the boolean value to return if <code>null</code> * @return <code>true</code> or <code>false</code> */ public static boolean toBooleanDefaultIfNull(Boolean bool, boolean valueIfNull) { if (bool == null) { return valueIfNull; } return bool.booleanValue() ? true : false; } // Integer to Boolean methods //----------------------------------------------------------------------- /** * <p>Converts an int to a boolean using the convention that <code>zero</code> * is <code>false</code>.</p> * * <pre> * BooleanUtils.toBoolean(0) = false * BooleanUtils.toBoolean(1) = true * BooleanUtils.toBoolean(2) = true * </pre> * * @param value the int to convert * @return <code>true</code> if non-zero, <code>false</code> * if zero */ public static boolean toBoolean(int value) { return value == 0 ? false : true; } /** * <p>Converts an int to a Boolean using the convention that <code>zero</code> * is <code>false</code>.</p> * * <pre> * BooleanUtils.toBoolean(0) = Boolean.FALSE * BooleanUtils.toBoolean(1) = Boolean.TRUE * BooleanUtils.toBoolean(2) = Boolean.TRUE * </pre> * * @param value the int to convert * @return Boolean.TRUE if non-zero, Boolean.FALSE if zero, * <code>null</code> if <code>null</code> */ public static Boolean toBooleanObject(int value) { return value == 0 ? Boolean.FALSE : Boolean.TRUE; } /** * <p>Converts an Integer to a Boolean using the convention that <code>zero</code> * is <code>false</code>.</p> * * <p><code>null</code> will be converted to <code>null</code>.</p> * * <pre> * BooleanUtils.toBoolean(new Integer(0)) = Boolean.FALSE * BooleanUtils.toBoolean(new Integer(1)) = Boolean.TRUE * BooleanUtils.toBoolean(new Integer(null)) = null * </pre> * * @param value the Integer to convert * @return Boolean.TRUE if non-zero, Boolean.FALSE if zero, * <code>null</code> if <code>null</code> input */ public static Boolean toBooleanObject(Integer value) { if (value == null) { return null; } return value.intValue() == 0 ? Boolean.FALSE : Boolean.TRUE; } /** * <p>Converts an int to a boolean specifying the conversion values.</p> * * <pre> * BooleanUtils.toBoolean(0, 1, 0) = false * BooleanUtils.toBoolean(1, 1, 0) = true * BooleanUtils.toBoolean(2, 1, 2) = false * BooleanUtils.toBoolean(2, 2, 0) = true * </pre> * * @param value the Integer to convert * @param trueValue the value to match for <code>true</code> * @param falseValue the value to match for <code>false</code> * @return <code>true</code> or <code>false</code> * @throws IllegalArgumentException if no match */ public static boolean toBoolean(int value, int trueValue, int falseValue) { if (value == trueValue) { return true; } else if (value == falseValue) { return false; } // no match throw new IllegalArgumentException("The Integer did not match either specified value"); } /** * <p>Converts an Integer to a boolean specifying the conversion values.</p> * * <pre> * BooleanUtils.toBoolean(new Integer(0), new Integer(1), new Integer(0)) = false * BooleanUtils.toBoolean(new Integer(1), new Integer(1), new Integer(0)) = true * BooleanUtils.toBoolean(new Integer(2), new Integer(1), new Integer(2)) = false * BooleanUtils.toBoolean(new Integer(2), new Integer(2), new Integer(0)) = true * BooleanUtils.toBoolean(null, null, new Integer(0)) = true * </pre> * * @param value the Integer to convert * @param trueValue the value to match for <code>true</code>, * may be <code>null</code> * @param falseValue the value to match for <code>false</code>, * may be <code>null</code> * @return <code>true</code> or <code>false</code> * @throws IllegalArgumentException if no match */ public static boolean toBoolean(Integer value, Integer trueValue, Integer falseValue) { if (value == null) { if (trueValue == null) { return true; } else if (falseValue == null) { return false; } } else if (value.equals(trueValue)) { return true; } else if (value.equals(falseValue)) { return false; } // no match throw new IllegalArgumentException("The Integer did not match either specified value"); } /** * <p>Converts an int to a Boolean specifying the conversion values.</p> * * <pre> * BooleanUtils.toBooleanObject(0, 0, 2, 3) = Boolean.TRUE * BooleanUtils.toBooleanObject(2, 1, 2, 3) = Boolean.FALSE * BooleanUtils.toBooleanObject(3, 1, 2, 3) = null * </pre> * * @param value the Integer to convert * @param trueValue the value to match for <code>true</code> * @param falseValue the value to match for <code>false</code> * @param nullValue the value to to match for <code>null</code> * @return Boolean.TRUE, Boolean.FALSE, or <code>null</code> * @throws IllegalArgumentException if no match */ public static Boolean toBooleanObject(int value, int trueValue, int falseValue, int nullValue) { if (value == trueValue) { return Boolean.TRUE; } else if (value == falseValue) { return Boolean.FALSE; } else if (value == nullValue) { return null; } // no match throw new IllegalArgumentException("The Integer did not match any specified value"); } /** * <p>Converts an Integer to a Boolean specifying the conversion values.</p> * * <pre> * BooleanUtils.toBooleanObject(new Integer(0), new Integer(0), new Integer(2), new Integer(3)) = Boolean.TRUE * BooleanUtils.toBooleanObject(new Integer(2), new Integer(1), new Integer(2), new Integer(3)) = Boolean.FALSE * BooleanUtils.toBooleanObject(new Integer(3), new Integer(1), new Integer(2), new Integer(3)) = null * </pre> * * @param value the Integer to convert * @param trueValue the value to match for <code>true</code>, * may be <code>null</code> * @param falseValue the value to match for <code>false</code>, * may be <code>null</code> * @param nullValue the value to to match for <code>null</code>, * may be <code>null</code> * @return Boolean.TRUE, Boolean.FALSE, or <code>null</code> * @throws IllegalArgumentException if no match */ public static Boolean toBooleanObject(Integer value, Integer trueValue, Integer falseValue, Integer nullValue) { if (value == null) { if (trueValue == null) { return Boolean.TRUE; } else if (falseValue == null) { return Boolean.FALSE; } else if (nullValue == null) { return null; } } else if (value.equals(trueValue)) { return Boolean.TRUE; } else if (value.equals(falseValue)) { return Boolean.FALSE; } else if (value.equals(nullValue)) { return null; } // no match throw new IllegalArgumentException("The Integer did not match any specified value"); } // Boolean to Integer methods //----------------------------------------------------------------------- /** * <p>Converts a boolean to an int using the convention that * <code>zero</code> is <code>false</code>.</p> * * <pre> * BooleanUtils.toInteger(true) = 1 * BooleanUtils.toInteger(false) = 0 * </pre> * * @param bool the boolean to convert * @return one if <code>true</code>, zero if <code>false</code> */ public static int toInteger(boolean bool) { return bool ? 1 : 0; } /** * <p>Converts a boolean to an Integer using the convention that * <code>zero</code> is <code>false</code>.</p> * * <pre> * BooleanUtils.toIntegerObject(true) = new Integer(1) * BooleanUtils.toIntegerObject(false) = new Integer(0) * </pre> * * @param bool the boolean to convert * @return one if <code>true</code>, zero if <code>false</code> */ public static Integer toIntegerObject(boolean bool) { return bool ? NumberUtils.INTEGER_ONE : NumberUtils.INTEGER_ZERO; } /** * <p>Converts a Boolean to a Integer using the convention that * <code>zero</code> is <code>false</code>.</p> * * <p><code>null</code> will be converted to <code>null</code>.</p> * * <pre> * BooleanUtils.toIntegerObject(Boolean.TRUE) = new Integer(1) * BooleanUtils.toIntegerObject(Boolean.FALSE) = new Integer(0) * </pre> * * @param bool the Boolean to convert * @return one if Boolean.TRUE, zero if Boolean.FALSE, <code>null</code> if <code>null</code> */ public static Integer toIntegerObject(Boolean bool) { if (bool == null) { return null; } return bool.booleanValue() ? NumberUtils.INTEGER_ONE : NumberUtils.INTEGER_ZERO; } /** * <p>Converts a boolean to an int specifying the conversion values.</p> * * <pre> * BooleanUtils.toInteger(true, 1, 0) = 1 * BooleanUtils.toInteger(false, 1, 0) = 0 * </pre> * * @param bool the to convert * @param trueValue the value to return if <code>true</code> * @param falseValue the value to return if <code>false</code> * @return the appropriate value */ public static int toInteger(boolean bool, int trueValue, int falseValue) { return bool ? trueValue : falseValue; } /** * <p>Converts a Boolean to an int specifying the conversion values.</p> * * <pre> * BooleanUtils.toInteger(Boolean.TRUE, 1, 0, 2) = 1 * BooleanUtils.toInteger(Boolean.FALSE, 1, 0, 2) = 0 * BooleanUtils.toInteger(null, 1, 0, 2) = 2 * </pre> * * @param bool the Boolean to convert * @param trueValue the value to return if <code>true</code> * @param falseValue the value to return if <code>false</code> * @param nullValue the value to return if <code>null</code> * @return the appropriate value */ public static int toInteger(Boolean bool, int trueValue, int falseValue, int nullValue) { if (bool == null) { return nullValue; } return bool.booleanValue() ? trueValue : falseValue; } /** * <p>Converts a boolean to an Integer specifying the conversion values.</p> * * <pre> * BooleanUtils.toIntegerObject(true, new Integer(1), new Integer(0)) = new Integer(1) * BooleanUtils.toIntegerObject(false, new Integer(1), new Integer(0)) = new Integer(0) * </pre> * * @param bool the to convert * @param trueValue the value to return if <code>true</code>, * may be <code>null</code> * @param falseValue the value to return if <code>false</code>, * may be <code>null</code> * @return the appropriate value */ public static Integer toIntegerObject(boolean bool, Integer trueValue, Integer falseValue) { return bool ? trueValue : falseValue; } /** * <p>Converts a Boolean to an Integer specifying the conversion values.</p> * * <pre> * BooleanUtils.toIntegerObject(Boolean.TRUE, new Integer(1), new Integer(0), new Integer(2)) = new Integer(1) * BooleanUtils.toIntegerObject(Boolean.FALSE, new Integer(1), new Integer(0), new Integer(2)) = new Integer(0) * BooleanUtils.toIntegerObject(null, new Integer(1), new Integer(0), new Integer(2)) = new Integer(2) * </pre> * * @param bool the Boolean to convert * @param trueValue the value to return if <code>true</code>, * may be <code>null</code> * @param falseValue the value to return if <code>false</code>, * may be <code>null</code> * @param nullValue the value to return if <code>null</code>, * may be <code>null</code> * @return the appropriate value */ public static Integer toIntegerObject(Boolean bool, Integer trueValue, Integer falseValue, Integer nullValue) { if (bool == null) { return nullValue; } return bool.booleanValue() ? trueValue : falseValue; } // String to Boolean methods //----------------------------------------------------------------------- /** * <p>Converts a String to a Boolean.</p> * * <p><code>'true'</code>, <code>'on'</code> or <code>'yes'</code> * (case insensitive) will return <code>true</code>. * <code>'false'</code>, <code>'off'</code> or <code>'no'</code> * (case insensitive) will return <code>false</code>. * Otherwise, <code>null</code> is returned.</p> * * <pre> * BooleanUtils.toBooleanObject(null) = null * BooleanUtils.toBooleanObject("true") = Boolean.TRUE * BooleanUtils.toBooleanObject("false") = Boolean.FALSE * BooleanUtils.toBooleanObject("on") = Boolean.TRUE * BooleanUtils.toBooleanObject("ON") = Boolean.TRUE * BooleanUtils.toBooleanObject("off") = Boolean.FALSE * BooleanUtils.toBooleanObject("oFf") = Boolean.FALSE * BooleanUtils.toBooleanObject("blue") = null * </pre> * * @param str the String to check * @return the Boolean value of the string, * <code>null</code> if no match or <code>null</code> input */ public static Boolean toBooleanObject(String str) { if ("true".equalsIgnoreCase(str)) { return Boolean.TRUE; } else if ("false".equalsIgnoreCase(str)) { return Boolean.FALSE; } else if ("on".equalsIgnoreCase(str)) { return Boolean.TRUE; } else if ("off".equalsIgnoreCase(str)) { return Boolean.FALSE; } else if ("yes".equalsIgnoreCase(str)) { return Boolean.TRUE; } else if ("no".equalsIgnoreCase(str)) { return Boolean.FALSE; } // no match return null; } /** * <p>Converts a String to a Boolean throwing an exception if no match.</p> * * <pre> * BooleanUtils.toBooleanObject("true", "true", "false", "null") = Boolean.TRUE * BooleanUtils.toBooleanObject("false", "true", "false", "null") = Boolean.FALSE * BooleanUtils.toBooleanObject("null", "true", "false", "null") = null * </pre> * * @param str the String to check * @param trueString the String to match for <code>true</code> * (case sensitive), may be <code>null</code> * @param falseString the String to match for <code>false</code> * (case sensitive), may be <code>null</code> * @param nullString the String to match for <code>null</code> * (case sensitive), may be <code>null</code> * @return the Boolean value of the string, * <code>null</code> if either the String matches <code>nullString</code> * or if <code>null</code> input and <code>nullString</code> is * <code>null</code> * @throws IllegalArgumentException if the String doesn't match */ public static Boolean toBooleanObject(String str, String trueString, String falseString, String nullString) { if (str == null) { if (trueString == null) { return Boolean.TRUE; } else if (falseString == null) { return Boolean.FALSE; } else if (nullString == null) { return null; } } else if (str.equals(trueString)) { return Boolean.TRUE; } else if (str.equals(falseString)) { return Boolean.FALSE; } else if (str.equals(nullString)) { return null; } // no match throw new IllegalArgumentException("The String did not match any specified value"); } // String to boolean methods //----------------------------------------------------------------------- /** * <p>Converts a String to a boolean (optimised for performance).</p> * * <p><code>'true'</code>, <code>'on'</code> or <code>'yes'</code> * (case insensitive) will return <code>true</code>. Otherwise, * <code>false</code> is returned.</p> * * <p>This method performs 4 times faster (JDK1.4) than * <code>Boolean.valueOf(String)</code>. However, this method accepts * 'on' and 'yes' as true values. * * <pre> * BooleanUtils.toBoolean(null) = false * BooleanUtils.toBoolean("true") = true * BooleanUtils.toBoolean("TRUE") = true * BooleanUtils.toBoolean("tRUe") = true * BooleanUtils.toBoolean("on") = true * BooleanUtils.toBoolean("yes") = true * BooleanUtils.toBoolean("false") = false * BooleanUtils.toBoolean("x gti") = false * </pre> * * @param str the String to check * @return the boolean value of the string, <code>false</code> if no match */ public static boolean toBoolean(String str) { // Previously used equalsIgnoreCase, which was fast for interned 'true'. // Non interned 'true' matched 15 times slower. // // Optimisation provides same performance as before for interned 'true'. // Similar performance for null, 'false', and other strings not length 2/3/4. // 'true'/'TRUE' match 4 times slower, 'tRUE'/'True' 7 times slower. if (str == "true") { return true; } if (str == null) { return false; } switch (str.length()) { case 2: { char ch0 = str.charAt(0); char ch1 = str.charAt(1); return (ch0 == 'o' || ch0 == 'O') && (ch1 == 'n' || ch1 == 'N'); } case 3: { char ch = str.charAt(0); if (ch == 'y') { return (str.charAt(1) == 'e' || str.charAt(1) == 'E') && (str.charAt(2) == 's' || str.charAt(2) == 'S'); } if (ch == 'Y') { return (str.charAt(1) == 'E' || str.charAt(1) == 'e') && (str.charAt(2) == 'S' || str.charAt(2) == 's'); } return false; } case 4: { char ch = str.charAt(0); if (ch == 't') { return (str.charAt(1) == 'r' || str.charAt(1) == 'R') && (str.charAt(2) == 'u' || str.charAt(2) == 'U') && (str.charAt(3) == 'e' || str.charAt(3) == 'E'); } if (ch == 'T') { return (str.charAt(1) == 'R' || str.charAt(1) == 'r') && (str.charAt(2) == 'U' || str.charAt(2) == 'u') && (str.charAt(3) == 'E' || str.charAt(3) == 'e'); } } } return false; } // public static void main(String[] args) { // long start = System.currentTimeMillis(); // boolean flag = true; // int count = 0; // for (int i = 0; i < 100000000; i++) { // flag = toBoolean("YES"); // } // long end = System.currentTimeMillis(); // System.out.println((end - start) + " " + flag + " " + count); // } /** * <p>Converts a String to a Boolean throwing an exception if no match found.</p> * * <p>null is returned if there is no match.</p> * * <pre> * BooleanUtils.toBoolean("true", "true", "false") = true * BooleanUtils.toBoolean("false", "true", "false") = false * </pre> * * @param str the String to check * @param trueString the String to match for <code>true</code> * (case sensitive), may be <code>null</code> * @param falseString the String to match for <code>false</code> * (case sensitive), may be <code>null</code> * @return the boolean value of the string * @throws IllegalArgumentException if the String doesn't match */ public static boolean toBoolean(String str, String trueString, String falseString) { if (str == null) { if (trueString == null) { return true; } else if (falseString == null) { return false; } } else if (str.equals(trueString)) { return true; } else if (str.equals(falseString)) { return false; } // no match throw new IllegalArgumentException("The String did not match either specified value"); } // Boolean to String methods //----------------------------------------------------------------------- /** * <p>Converts a Boolean to a String returning <code>'true'</code>, * <code>'false'</code>, or <code>null</code>.</p> * * <pre> * BooleanUtils.toStringTrueFalse(Boolean.TRUE) = "true" * BooleanUtils.toStringTrueFalse(Boolean.FALSE) = "false" * BooleanUtils.toStringTrueFalse(null) = null; * </pre> * * @param bool the Boolean to check * @return <code>'true'</code>, <code>'false'</code>, * or <code>null</code> */ public static String toStringTrueFalse(Boolean bool) { return toString(bool, "true", "false", null); } /** * <p>Converts a Boolean to a String returning <code>'on'</code>, * <code>'off'</code>, or <code>null</code>.</p> * * <pre> * BooleanUtils.toStringOnOff(Boolean.TRUE) = "on" * BooleanUtils.toStringOnOff(Boolean.FALSE) = "off" * BooleanUtils.toStringOnOff(null) = null; * </pre> * * @param bool the Boolean to check * @return <code>'on'</code>, <code>'off'</code>, * or <code>null</code> */ public static String toStringOnOff(Boolean bool) { return toString(bool, "on", "off", null); } /** * <p>Converts a Boolean to a String returning <code>'yes'</code>, * <code>'no'</code>, or <code>null</code>.</p> * * <pre> * BooleanUtils.toStringYesNo(Boolean.TRUE) = "yes" * BooleanUtils.toStringYesNo(Boolean.FALSE) = "no" * BooleanUtils.toStringYesNo(null) = null; * </pre> * * @param bool the Boolean to check * @return <code>'yes'</code>, <code>'no'</code>, * or <code>null</code> */ public static String toStringYesNo(Boolean bool) { return toString(bool, "yes", "no", null); } /** * <p>Converts a Boolean to a String returning one of the input Strings.</p> * * <pre> * BooleanUtils.toString(Boolean.TRUE, "true", "false", null) = "true" * BooleanUtils.toString(Boolean.FALSE, "true", "false", null) = "false" * BooleanUtils.toString(null, "true", "false", null) = null; * </pre> * * @param bool the Boolean to check * @param trueString the String to return if <code>true</code>, * may be <code>null</code> * @param falseString the String to return if <code>false</code>, * may be <code>null</code> * @param nullString the String to return if <code>null</code>, * may be <code>null</code> * @return one of the three input Strings */ public static String toString(Boolean bool, String trueString, String falseString, String nullString) { if (bool == null) { return nullString; } return bool.booleanValue() ? trueString : falseString; } // boolean to String methods //----------------------------------------------------------------------- /** * <p>Converts a boolean to a String returning <code>'true'</code> * or <code>'false'</code>.</p> * * <pre> * BooleanUtils.toStringTrueFalse(true) = "true" * BooleanUtils.toStringTrueFalse(false) = "false" * </pre> * * @param bool the Boolean to check * @return <code>'true'</code>, <code>'false'</code>, * or <code>null</code> */ public static String toStringTrueFalse(boolean bool) { return toString(bool, "true", "false"); } /** * <p>Converts a boolean to a String returning <code>'on'</code> * or <code>'off'</code>.</p> * * <pre> * BooleanUtils.toStringOnOff(true) = "on" * BooleanUtils.toStringOnOff(false) = "off" * </pre> * * @param bool the Boolean to check * @return <code>'on'</code>, <code>'off'</code>, * or <code>null</code> */ public static String toStringOnOff(boolean bool) { return toString(bool, "on", "off"); } /** * <p>Converts a boolean to a String returning <code>'yes'</code> * or <code>'no'</code>.</p> * * <pre> * BooleanUtils.toStringYesNo(true) = "yes" * BooleanUtils.toStringYesNo(false) = "no" * </pre> * * @param bool the Boolean to check * @return <code>'yes'</code>, <code>'no'</code>, * or <code>null</code> */ public static String toStringYesNo(boolean bool) { return toString(bool, "yes", "no"); } /** * <p>Converts a boolean to a String returning one of the input Strings.</p> * * <pre> * BooleanUtils.toString(true, "true", "false") = "true" * BooleanUtils.toString(false, "true", "false") = "false" * </pre> * * @param bool the Boolean to check * @param trueString the String to return if <code>true</code>, * may be <code>null</code> * @param falseString the String to return if <code>false</code>, * may be <code>null</code> * @return one of the two input Strings */ public static String toString(boolean bool, String trueString, String falseString) { return bool ? trueString : falseString; } // xor methods // ---------------------------------------------------------------------- /** * <p>Performs an xor on a set of booleans.</p> * * <pre> * BooleanUtils.xor(new boolean[] { true, true }) = false * BooleanUtils.xor(new boolean[] { false, false }) = false * BooleanUtils.xor(new boolean[] { true, false }) = true * </pre> * * @param array an array of <code>boolean<code>s * @return <code>true</code> if the xor is successful. * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty. */ public static boolean xor(boolean[] array) { // Validates input if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array is empty"); } // Loops through array, comparing each item int trueCount = 0; for (int i = 0; i < array.length; i++) { // If item is true, and trueCount is < 1, increments count // Else, xor fails if (array[i]) { if (trueCount < 1) { trueCount++; } else { return false; } } } // Returns true if there was exactly 1 true item return trueCount == 1; } /** * <p>Performs an xor on an array of Booleans.</p> * * <pre> * BooleanUtils.xor(new Boolean[] { Boolean.TRUE, Boolean.TRUE }) = Boolean.FALSE * BooleanUtils.xor(new Boolean[] { Boolean.FALSE, Boolean.FALSE }) = Boolean.FALSE * BooleanUtils.xor(new Boolean[] { Boolean.TRUE, Boolean.FALSE }) = Boolean.TRUE * </pre> * * @param array an array of <code>Boolean<code>s * @return <code>true</code> if the xor is successful. * @throws IllegalArgumentException if <code>array</code> is <code>null</code> * @throws IllegalArgumentException if <code>array</code> is empty. * @throws IllegalArgumentException if <code>array</code> contains a <code>null</code> */ public static Boolean xor(Boolean[] array) { if (array == null) { throw new IllegalArgumentException("The Array must not be null"); } else if (array.length == 0) { throw new IllegalArgumentException("Array is empty"); } boolean[] primitive = null; try { primitive = ArrayUtils.toPrimitive(array); } catch (NullPointerException ex) { throw new IllegalArgumentException("The array must not contain any null elements"); } return xor(primitive) ? Boolean.TRUE : Boolean.FALSE; } }