001/* 002 * The contents of this file are subject to the terms of the Common Development and 003 * Distribution License (the License). You may not use this file except in compliance with the 004 * License. 005 * 006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the 007 * specific language governing permission and limitations under the License. 008 * 009 * When distributing Covered Software, include this CDDL Header Notice in each file and include 010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL 011 * Header, with the fields enclosed by brackets [] replaced by your own identifying 012 * information: "Portions Copyright [year] [name of copyright owner]". 013 * 014 * Copyright 2010-2011 ApexIdentity Inc. 015 * Portions Copyright 2011-2015 ForgeRock AS. 016 */ 017 018package org.forgerock.openig.util; 019 020import java.util.Collections; 021import java.util.HashMap; 022import java.util.LinkedHashSet; 023import java.util.Map; 024import java.util.Set; 025 026/** 027 * Utility class for accessing Java enum types. 028 */ 029public final class EnumUtil { 030 031 /** Cache of name sets for repeated call efficiency. */ 032 private static final Map<Class<?>, Set<String>> NAMESETS = new HashMap<>(); 033 034 /** Static methods only. */ 035 private EnumUtil() { 036 } 037 038 /** 039 * Returns a set of the names of the enum constants of the specified enum type. The 040 * returned set maintains iteration order of the constants in the order they're declared 041 * in the enum type. 042 * 043 * @param enumType the class of the enum type from which to return the names. 044 * @param <T> enumeration type 045 * @return a set of the names of the enum constants in the specified enum. 046 */ 047 public static <T extends Enum<T>> Set<String> names(Class<T> enumType) { 048 Set<String> set = NAMESETS.get(enumType); 049 if (set == null) { 050 // cached for repeated call efficiency 051 set = new LinkedHashSet<>(); 052 for (T constant : enumType.getEnumConstants()) { 053 set.add(constant.toString()); 054 } 055 NAMESETS.put(enumType, Collections.unmodifiableSet(set)); 056 } 057 return set; 058 } 059 060 /** 061 * Returns the enum constant of the specified enum type with the specified name, or 062 * {@code null} if the specified enum type has no constant with the specified name, or 063 * if the specified class object does not represent an enum type. 064 * 065 * @param enumType the class of the enum type from which to return a constant. 066 * @param name the name of the constant to return. 067 * @param <T> enumeration type 068 * @return the matching enum constant or {@code null} if no match found. 069 */ 070 public static <T extends Enum<T>> T valueOf(Class<T> enumType, Object name) { 071 T value = null; 072 if (name instanceof CharSequence) { 073 try { 074 value = Enum.valueOf(enumType, name.toString()); 075 } catch (IllegalArgumentException iae) { 076 // result in null return value 077 } 078 } 079 return value; 080 } 081}