001 /*--------------------------------------------------------------------------+ 002 $Id: EnumUtils.java 26268 2010-02-18 10:44:30Z juergens $ 003 | | 004 | Copyright 2005-2010 Technische Universitaet Muenchen | 005 | | 006 | Licensed under the Apache License, Version 2.0 (the "License"); | 007 | you may not use this file except in compliance with the License. | 008 | You may obtain a copy of the License at | 009 | | 010 | http://www.apache.org/licenses/LICENSE-2.0 | 011 | | 012 | Unless required by applicable law or agreed to in writing, software | 013 | distributed under the License is distributed on an "AS IS" BASIS, | 014 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 015 | See the License for the specific language governing permissions and | 016 | limitations under the License. | 017 +--------------------------------------------------------------------------*/ 018 package edu.tum.cs.commons.enums; 019 020 import edu.tum.cs.commons.assertion.CCSMAssert; 021 022 /** 023 * Utility class for enumerations. 024 * 025 * @author Florian Deissenboeck 026 * @author $Author: juergens $ 027 * 028 * @version $Rev: 26268 $ 029 * @levd.rating GREEN Hash: C7E378E216DC3DABDB774FCA63D04260 030 */ 031 public class EnumUtils { 032 033 /** 034 * This works like {@link Enum#valueOf(java.lang.Class, java.lang.String)} 035 * but returns <code>null</code> if constant wasn't found instead of 036 * throwing an <code>IllegalArgumentException</code>. 037 * 038 * @param enumType 039 * Enumeration class 040 * @param constantName 041 * name of the constant 042 * @return the matching constant or <code>null</code> if not found 043 */ 044 public static <T extends Enum<T>> T valueOf(Class<T> enumType, 045 String constantName) { 046 try { 047 T constant = Enum.valueOf(enumType, constantName); 048 return constant; 049 } catch (IllegalArgumentException ex) { 050 return null; 051 } 052 } 053 054 /** 055 * Works like {@link #valueOf(Class, String)} but ignores case. 056 * 057 * Worst case runtime is O('number of constants in enum'). 058 */ 059 public static <T extends Enum<T>> T valueOfIgnoreCase(Class<T> enumType, 060 String constantName) { 061 T[] constants = enumType.getEnumConstants(); 062 CCSMAssert.isNotNull(constants); 063 for (T constant : constants) { 064 if (constant.name().equalsIgnoreCase(constantName)) { 065 return constant; 066 } 067 } 068 return null; 069 } 070 071 /** 072 * Returns an array containing the names of the enum element. Ordering is 073 * same as element ordering in enum. 074 */ 075 public static <T extends Enum<T>> String[] stringValues(Class<T> enumType) { 076 T[] constants = enumType.getEnumConstants(); 077 CCSMAssert.isNotNull(constants); 078 String[] result = new String[constants.length]; 079 for (int i = 0; i < constants.length; i++) { 080 result[i] = constants[i].name(); 081 } 082 return result; 083 } 084 }