    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    }