001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.lang.enums;
018
019 import java.util.Iterator;
020 import java.util.List;
021 import java.util.Map;
022
023 /**
024 * <p>Utility class for accessing and manipulating {@link Enum}s.</p>
025 *
026 * @see Enum
027 * @see ValuedEnum
028 * @author Apache Software Foundation
029 * @author Gary Gregory
030 * @since 2.1 (class existed in enum package from v1.0)
031 * @version $Id: EnumUtils.java 905636 2010-02-02 14:03:32Z niallp $
032 */
033 public class EnumUtils {
034
035 /**
036 * Public constructor. This class should not normally be instantiated.
037 * @since 2.0
038 */
039 public EnumUtils() {
040 super();
041 }
042
043 /**
044 * <p>Gets an <code>Enum</code> object by class and name.</p>
045 *
046 * @param enumClass the class of the <code>Enum</code> to get
047 * @param name the name of the Enum to get, may be <code>null</code>
048 * @return the enum object
049 * @throws IllegalArgumentException if the enum class is <code>null</code>
050 */
051 public static Enum getEnum(Class enumClass, String name) {
052 return Enum.getEnum(enumClass, name);
053 }
054
055 /**
056 * <p>Gets a <code>ValuedEnum</code> object by class and value.</p>
057 *
058 * @param enumClass the class of the <code>Enum</code> to get
059 * @param value the value of the <code>Enum</code> to get
060 * @return the enum object, or null if the enum does not exist
061 * @throws IllegalArgumentException if the enum class is <code>null</code>
062 */
063 public static ValuedEnum getEnum(Class enumClass, int value) {
064 return (ValuedEnum) ValuedEnum.getEnum(enumClass, value);
065 }
066
067 /**
068 * <p>Gets the <code>Map</code> of <code>Enum</code> objects by
069 * name using the <code>Enum</code> class.</p>
070 *
071 * <p>If the requested class has no enum objects an empty
072 * <code>Map</code> is returned. The <code>Map</code> is unmodifiable.</p>
073 *
074 * @param enumClass the class of the <code>Enum</code> to get
075 * @return the enum object Map
076 * @throws IllegalArgumentException if the enum class is <code>null</code>
077 * @throws IllegalArgumentException if the enum class is not a subclass
078 * of <code>Enum</code>
079 */
080 public static Map getEnumMap(Class enumClass) {
081 return Enum.getEnumMap(enumClass);
082 }
083
084 /**
085 * <p>Gets the <code>List</code> of <code>Enum</code> objects using
086 * the <code>Enum</code> class.</p>
087 *
088 * <p>The list is in the order that the objects were created
089 * (source code order).</p>
090 *
091 * <p>If the requested class has no enum objects an empty
092 * <code>List</code> is returned. The <code>List</code> is unmodifiable.</p>
093 *
094 * @param enumClass the class of the Enum to get
095 * @return the enum object Map
096 * @throws IllegalArgumentException if the enum class is <code>null</code>
097 * @throws IllegalArgumentException if the enum class is not a subclass
098 * of <code>Enum</code>
099 */
100 public static List getEnumList(Class enumClass) {
101 return Enum.getEnumList(enumClass);
102 }
103
104 /**
105 * <p>Gets an <code>Iterator</code> over the <code>Enum</code> objects
106 * in an <code>Enum</code> class.</p>
107 *
108 * <p>The iterator is in the order that the objects were created
109 * (source code order).</p>
110 *
111 * <p>If the requested class has no enum objects an empty
112 * <code>Iterator</code> is returned. The <code>Iterator</code>
113 * is unmodifiable.</p>
114 *
115 * @param enumClass the class of the <code>Enum</code> to get
116 * @return an <code>Iterator</code> of the <code>Enum</code> objects
117 * @throws IllegalArgumentException if the enum class is <code>null</code>
118 * @throws IllegalArgumentException if the enum class is not a subclass of <code>Enum</code>
119 */
120 public static Iterator iterator(Class enumClass) {
121 return Enum.getEnumList(enumClass).iterator();
122 }
123
124 }