| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2002-2003 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, if |
| * any, must include the following acknowlegement: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowlegement may appear in the software itself, |
| * if and wherever such third-party acknowlegements normally appear. |
| * |
| * 4. The names "The Jakarta Project", "Commons", and "Apache Software |
| * Foundation" must not be used to endorse or promote products derived |
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| * 5. Products derived from this software may not be called "Apache" |
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| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.commons.lang.enum; |
| |
| import java.util.Iterator; |
| import java.util.List; |
| /** |
| * <p>Abstract superclass for type-safe enums with integer values suitable |
| * for use in <code>switch</code> statements.</p> |
| * |
| * <p><em>NOTE:</em>Due to the way in which Java ClassLoaders work, comparing |
| * <code>Enum</code> objects should always be done using the equals() method, |
| * not <code>==</code>. The equals() method will try <code>==</code> first so |
| * in most cases the effect is the same.</p> |
| * |
| * <p>To use this class, it must be subclassed. For example:</p> |
| * |
| * <pre> |
| * public final class JavaVersionEnum extends ValuedEnum { |
| * //standard enums for version of JVM |
| * public static final int JAVA1_0_VALUE = 100; |
| * public static final int JAVA1_1_VALUE = 110; |
| * public static final int JAVA1_2_VALUE = 120; |
| * public static final int JAVA1_3_VALUE = 130; |
| * public static final JavaVersionEnum JAVA1_0 = new JavaVersionEnum( "Java 1.0", JAVA1_0_VALUE ); |
| * public static final JavaVersionEnum JAVA1_1 = new JavaVersionEnum( "Java 1.1", JAVA1_1_VALUE ); |
| * public static final JavaVersionEnum JAVA1_2 = new JavaVersionEnum( "Java 1.2", JAVA1_2_VALUE ); |
| * public static final JavaVersionEnum JAVA1_3 = new JavaVersionEnum( "Java 1.3", JAVA1_3_VALUE ); |
| * |
| * private JavaVersionEnum(String name, int value) { |
| * super( name, value ); |
| * } |
| * |
| * public static JavaVersionEnum getEnum(String javaVersion) { |
| * return (JavaVersionEnum) getEnum(JavaVersionEnum.class, javaVersion); |
| * } |
| * |
| * public static JavaVersionEnum getEnum(int javaVersion) { |
| * return (JavaVersionEnum) getEnum(JavaVersionEnum.class, javaVersion); |
| * } |
| * |
| * public static Map getEnumMap() { |
| * return getEnumMap(JavaVersionEnum.class); |
| * } |
| * |
| * public static List getEnumList() { |
| * return getEnumList(JavaVersionEnum.class); |
| * } |
| * |
| * public static Iterator iterator() { |
| * return iterator(JavaVersionEnum.class); |
| * } |
| * } |
| * </pre> |
| * |
| * <p>The above class could then be used as follows:</p> |
| * |
| * <pre> |
| * public void doSomething(JavaVersion ver) { |
| * switch (ver.getValue()) { |
| * case JAVA1_0_VALUE: |
| * // ... |
| * break; |
| * case JAVA1_1_VALUE: |
| * // ... |
| * break; |
| * //... |
| * } |
| * } |
| * </pre> |
| * |
| * <p>As shown, each enum has a name and a value. These can be accessed using |
| * <code>getName</code> and <code>getValue</code>.</p> |
| * |
| * <p>The <code>getEnum</code> and <code>iterator</code> methods are recommended. |
| * Unfortunately, Java restrictions require these to be coded as shown in each subclass. |
| * An alternative choice is to use the {@link EnumUtils} class.</p> |
| * |
| * <p><em>NOTE:</em> This class originated in the Jakarta Avalon project.</p> |
| * |
| * @author Stephen Colebourne |
| * @since 1.0 |
| * @version $Id: ValuedEnum.java,v 1.6 2003/07/14 22:25:04 bayard Exp $ |
| */ |
| public abstract class ValuedEnum extends Enum { |
| /** |
| * The value contained in enum. |
| */ |
| private final int iValue; |
| |
| /** |
| * Constructor for enum item. |
| * |
| * @param name the name of enum item. |
| * @param value the value of enum item. |
| */ |
| protected ValuedEnum(String name, int value) { |
| super(name); |
| iValue = value; |
| } |
| |
| /** |
| * <p>Gets an <code>Enum</code> object by class and value.</p> |
| * |
| * <p>This method loops through the list of <code>Enum</code>, |
| * thus if there are many <code>Enum</code>s this will be |
| * slow.</p> |
| * |
| * @param enumClass the class of the <code>Enum</code> to get |
| * @param value the value of the <code>Enum</code> to get |
| * @return the enum object, or null if the enum does not exist |
| * @throws IllegalArgumentException if the enum class is <code>null</code> |
| */ |
| protected static Enum getEnum(Class enumClass, int value) { |
| if (enumClass == null) { |
| throw new IllegalArgumentException("The Enum Class must not be null"); |
| } |
| List list = Enum.getEnumList(enumClass); |
| for (Iterator it = list.iterator(); it.hasNext();) { |
| ValuedEnum enum = (ValuedEnum) it.next(); |
| if (enum.getValue() == value) { |
| return enum; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * <p>Get value of enum item.</p> |
| * |
| * @return the enum item's value. |
| */ |
| public final int getValue() { |
| return iValue; |
| } |
| |
| /** |
| * <p>Tests for order.</p> |
| * |
| * <p>The default ordering is numeric by value, but this |
| * can be overridden by subclasses.</p> |
| * |
| * @see java.lang.Comparable#compareTo(Object) |
| * @param other the other object to compare to |
| * @return -ve if this is less than the other object, +ve if greater than, |
| * <code>0</code> of equal |
| * @throws ClassCastException if other is not an <code>Enum</code> |
| * @throws NullPointerException if other is <code>null</code> |
| */ |
| public int compareTo(Object other) { |
| return iValue - ((ValuedEnum) other).iValue; |
| } |
| |
| /** |
| * <p>Human readable description of this <code>Enum</code> item.</p> |
| * |
| * <p>For use when debugging.</p> |
| * |
| * @return String in the form <code>type[name=value]</code>, for example: |
| * <code>JavaVersion[Java 1.0=100]</code>. Note that the package name is |
| * stripped from the type name. |
| */ |
| public String toString() { |
| String shortName = Enum.getEnumClass(getClass()).getName(); |
| int pos = shortName.lastIndexOf('.'); |
| if (pos != -1) { |
| shortName = shortName.substring(pos + 1); |
| } |
| shortName = shortName.replace('$', '.'); |
| return shortName + "[" + getName() + "=" + getValue() + "]"; |
| } |
| } |