1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.lang.enums;
18
19 import java.util.Iterator;
20 import java.util.List;
21 import java.util.Map;
22
23 /**
24 * <p>Utility class for accessing and manipulating {@link Enum}s.</p>
25 *
26 * @see Enum
27 * @see ValuedEnum
28 * @author Stephen Colebourne
29 * @author Gary Gregory
30 * @since 2.1 (class existed in enum package from v1.0)
31 * @version $Id: EnumUtils.java 437554 2006-08-28 06:21:41Z bayard $
32 */
33 public class EnumUtils {
34
35 /**
36 * Public constructor. This class should not normally be instantiated.
37 * @since 2.0
38 */
39 public EnumUtils() {
40 super();
41 }
42
43 /**
44 * <p>Gets an <code>Enum</code> object by class and name.</p>
45 *
46 * @param enumClass the class of the <code>Enum</code> to get
47 * @param name the name of the Enum to get, may be <code>null</code>
48 * @return the enum object
49 * @throws IllegalArgumentException if the enum class is <code>null</code>
50 */
51 public static Enum getEnum(Class enumClass, String name) {
52 return Enum.getEnum(enumClass, name);
53 }
54
55 /**
56 * <p>Gets a <code>ValuedEnum</code> object by class and value.</p>
57 *
58 * @param enumClass the class of the <code>Enum</code> to get
59 * @param value the value of the <code>Enum</code> to get
60 * @return the enum object, or null if the enum does not exist
61 * @throws IllegalArgumentException if the enum class is <code>null</code>
62 */
63 public static ValuedEnum getEnum(Class enumClass, int value) {
64 return (ValuedEnum) ValuedEnum.getEnum(enumClass, value);
65 }
66
67 /**
68 * <p>Gets the <code>Map</code> of <code>Enum</code> objects by
69 * name using the <code>Enum</code> class.</p>
70 *
71 * <p>If the requested class has no enum objects an empty
72 * <code>Map</code> is returned. The <code>Map</code> is unmodifiable.</p>
73 *
74 * @param enumClass the class of the <code>Enum</code> to get
75 * @return the enum object Map
76 * @throws IllegalArgumentException if the enum class is <code>null</code>
77 * @throws IllegalArgumentException if the enum class is not a subclass
78 * of <code>Enum</code>
79 */
80 public static Map getEnumMap(Class enumClass) {
81 return Enum.getEnumMap(enumClass);
82 }
83
84 /**
85 * <p>Gets the <code>List</code> of <code>Enum</code> objects using
86 * the <code>Enum</code> class.</p>
87 *
88 * <p>The list is in the order that the objects were created
89 * (source code order).</p>
90 *
91 * <p>If the requested class has no enum objects an empty
92 * <code>List</code> is returned. The <code>List</code> is unmodifiable.</p>
93 *
94 * @param enumClass the class of the Enum to get
95 * @return the enum object Map
96 * @throws IllegalArgumentException if the enum class is <code>null</code>
97 * @throws IllegalArgumentException if the enum class is not a subclass
98 * of <code>Enum</code>
99 */
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 }