Java tutorial
//package com.java2s; /* * 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. */ public class Main { /** * <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 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.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"); } /** * <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) { // 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 Boolean.TRUE; } if (str == null) { return null; } switch (str.length()) { case 1: { char ch0 = str.charAt(0); if ((ch0 == 'y' || ch0 == 'Y') || (ch0 == 't' || ch0 == 'T')) { return Boolean.TRUE; } if ((ch0 == 'n' || ch0 == 'N') || (ch0 == 'f' || ch0 == 'F')) { return Boolean.FALSE; } break; } case 2: { char ch0 = str.charAt(0); char ch1 = str.charAt(1); if ((ch0 == 'o' || ch0 == 'O') && (ch1 == 'n' || ch1 == 'N')) { return Boolean.TRUE; } if ((ch0 == 'n' || ch0 == 'N') && (ch1 == 'o' || ch1 == 'O')) { return Boolean.FALSE; } break; } case 3: { char ch0 = str.charAt(0); char ch1 = str.charAt(1); char ch2 = str.charAt(2); if ((ch0 == 'y' || ch0 == 'Y') && (ch1 == 'e' || ch1 == 'E') && (ch2 == 's' || ch2 == 'S')) { return Boolean.TRUE; } if ((ch0 == 'o' || ch0 == 'O') && (ch1 == 'f' || ch1 == 'F') && (ch2 == 'f' || ch2 == 'F')) { return Boolean.FALSE; } break; } case 4: { char ch0 = str.charAt(0); char ch1 = str.charAt(1); char ch2 = str.charAt(2); char ch3 = str.charAt(3); if ((ch0 == 't' || ch0 == 'T') && (ch1 == 'r' || ch1 == 'R') && (ch2 == 'u' || ch2 == 'U') && (ch3 == 'e' || ch3 == 'E')) { return Boolean.TRUE; } break; } case 5: { char ch0 = str.charAt(0); char ch1 = str.charAt(1); char ch2 = str.charAt(2); char ch3 = str.charAt(3); char ch4 = str.charAt(4); if ((ch0 == 'f' || ch0 == 'F') && (ch1 == 'a' || ch1 == 'A') && (ch2 == 'l' || ch2 == 'L') && (ch3 == 's' || ch3 == 'S') && (ch4 == 'e' || ch4 == 'E')) { return Boolean.FALSE; } break; } } 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"); } }