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commons-lang-1.0.1.jar - Apache Commons Lang
commons-lang-1.0.1.jar is the JAR file for Apache Commons Lang 1.0.1, which provides a host of helper utilities for the java.lang API.
JAR File Size and Download Location:
File name: commons-lang-1.0.1.jar File size: 63980 bytes Date modified: 11/22/2002 Download: Apache Commons Lang Website
✍: FYIcenter.com
⏎ org/apache/commons/lang/enum/Enum.java
/* ==================================================================== * The Apache Software License, Version 1.1 * * Copyright (c) 2002 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 * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * 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.io.Serializable; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; /** * Abstract superclass for type-safe enums. * <p> * One feature of the C programming language lacking in Java is enumerations. The * C implementation based on ints was poor and open to abuse. The original Java * recommendation and most of the JDK also uses int constants. It has been recognised * however that a more robust type-safe class-based solution can be designed. This * class follows the basic Java type-safe enumeration pattern. * <p> * <em>NOTE:</em>Due to the way in which Java ClassLoaders work, comparing Enum objects * should always be done using the equals() method, not ==. The equals() method will * try == first so in most cases the effect is the same. * <p> * To use this class, it must be subclassed. For example: * * <pre> * public final class ColorEnum extends Enum { * public static final ColorEnum RED = new ColorEnum("Red"); * public static final ColorEnum GREEN = new ColorEnum("Green"); * public static final ColorEnum BLUE = new ColorEnum("Blue"); * * private ColorEnum(String color) { * super(color); * } * * public static ColorEnum getEnum(String color) { * return (ColorEnum) getEnum(ColorEnum.class, color); * } * * public static Map getEnumMap() { * return getEnumMap(ColorEnum.class); * } * * public static List getEnumList() { * return getEnumList(ColorEnum.class); * } * * public static Iterator iterator() { * return iterator(ColorEnum.class); * } * } * </pre> * <p> * As shown, each enum has a name. This can be accessed using <code>getName</code>. * <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> * <em>NOTE:</em> This class originated in the Jakarta Avalon project. * </p> * * @author <a href="mailto:scolebourne@joda.org">Stephen Colebourne</a> * @version $Id: Enum.java,v 1.2.2.1 2002/11/22 20:07:53 bayard Exp $ */ public abstract class Enum implements Comparable, Serializable { /** * An empty map, as JDK1.2 didn't have an empty map */ private static final Map EMPTY_MAP = Collections.unmodifiableMap(new HashMap()); /** * Map, key of class name, value of Entry. */ private static final Map cEnumClasses = new HashMap(); /** * The string representation of the Enum. */ private final String iName; /** * Enable the iterator to retain the source code order */ private static class Entry { /** Map of Enum name to Enum */ final Map map = new HashMap(50); /** List of Enums in source code order */ final List list = new ArrayList(25); /** * Restrictive constructor */ private Entry() { } } /** * Constructor to add a new named item to the enumeration. * * @param name the name of the enum object * @throws IllegalArgumentException if the name is null or a blank string */ protected Enum(String name) { super(); if (name == null || name.length() == 0) { throw new IllegalArgumentException("The Enum name must not be empty"); } iName = name; Entry entry = (Entry) cEnumClasses.get(getClass().getName()); if (entry == null) { entry = new Entry(); cEnumClasses.put(getClass().getName(), entry); } if (entry.map.containsKey(name)) { throw new IllegalArgumentException("The Enum name must be unique, '" + name + "' has already been added"); } entry.map.put(name, this); entry.list.add(this); } /** * Handle the deserialization of the class to ensure that multiple * copies are not wastefully created, or illegal enum types created. * @return the resolved object */ protected Object readResolve() { return Enum.getEnum(getClass(), getName()); } /** * Gets an Enum object by class and name. * * @param enumClass the class of the Enum to get * @param name the name of the Enum to get, may be null * @return the enum object, or null if the enum does not exist * @throws IllegalArgumentException if the enum class is null */ protected static Enum getEnum(Class enumClass, String name) { if (enumClass == null) { throw new IllegalArgumentException("The Enum Class must not be null"); } Entry entry = (Entry) cEnumClasses.get(enumClass.getName()); if (entry == null) { return null; } return (Enum) entry.map.get(name); } /** * Gets the Map of Enum objects by name using the Enum class. * If the requested class has no enum objects an empty Map is returned. * * @param enumClass the class of the Enum to get * @return the enum object Map * @throws IllegalArgumentException if the enum class is null * @throws IllegalArgumentException if the enum class is not a subclass of Enum */ protected static Map getEnumMap(Class enumClass) { if (enumClass == null) { throw new IllegalArgumentException("The Enum Class must not be null"); } if (Enum.class.isAssignableFrom(enumClass) == false) { throw new IllegalArgumentException("The Class must be a subclass of Enum"); } Entry entry = (Entry) cEnumClasses.get(enumClass.getName()); if (entry == null) { return EMPTY_MAP; } return Collections.unmodifiableMap(entry.map); } /** * Gets the List of Enum objects using the Enum class. * The list is in the order that the objects were created (source code order). * If the requested class has no enum objects an empty List is returned. * * @param enumClass the class of the Enum to get * @return the enum object Map * @throws IllegalArgumentException if the enum class is null * @throws IllegalArgumentException if the enum class is not a subclass of Enum */ protected static List getEnumList(Class enumClass) { if (enumClass == null) { throw new IllegalArgumentException("The Enum Class must not be null"); } if (Enum.class.isAssignableFrom(enumClass) == false) { throw new IllegalArgumentException("The Class must be a subclass of Enum"); } Entry entry = (Entry) cEnumClasses.get(enumClass.getName()); if (entry == null) { return Collections.EMPTY_LIST; } return Collections.unmodifiableList(entry.list); } /** * Gets an iterator over the Enum objects in an Enum class. * The iterator is in the order that the objects were created (source code order). * If the requested class has no enum objects an empty Iterator is returned. * * @param enumClass the class of the Enum to get * @return an iterator of the Enum objects * @throws IllegalArgumentException if the enum class is null * @throws IllegalArgumentException if the enum class is not a subclass of Enum */ protected static Iterator iterator(Class enumClass) { return Enum.getEnumList(enumClass).iterator(); } /** * Retrieve the name of this Enum item, set in the constructor. * * @return the <code>String</code> name of this Enum item */ public final String getName() { return iName; } /** * Tests for equality. Two Enum objects are considered equal * if they have the same class names and the same names. * Identity is tested for first, so this method usually runs fast. * * @param other the other object to compare for equality * @return true if the Enums are equal */ public final boolean equals(Object other) { if (other == this) { return true; } else if (other == null) { return false; } else if (other.getClass() == this.getClass()) { // shouldn't happen, but... return iName.equals(((Enum) other).iName); } else if (other.getClass().getName().equals(this.getClass().getName())) { // different classloaders try { // try to avoid reflection return iName.equals(((Enum) other).iName); } catch (ClassCastException ex) { // use reflection try { Method mth = other.getClass().getMethod("getName", null); String name = (String) mth.invoke(other, null); return iName.equals(name); } catch (NoSuchMethodException ex2) { // ignore - should never happen } catch (IllegalAccessException ex2) { // ignore - should never happen } catch (InvocationTargetException ex2) { // ignore - should never happen } return false; } } else { return false; } } /** * Returns a suitable hashCode for the enumeration. * * @return a hashcode based on the name */ public final int hashCode() { return 7 + iName.hashCode(); } /** * Tests for order. The default ordering is alphabetic by name, but this * can be overridden by subclasses. * * @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, 0 of equal * @throws ClassCastException if other is not an Enum * @throws NullPointerException if other is null */ public int compareTo(Object other) { return iName.compareTo(((Enum) other).iName); } /** * Human readable description of this Enum item. For use when debugging. * * @return String in the form <code>type[name]</code>, for example: * <code>Color[Red]</code>. Note that the package name is stripped from * the type name. */ public String toString() { String shortName = getClass().getName(); int pos = shortName.lastIndexOf('.'); if (pos != -1) { shortName = shortName.substring(pos + 1); } return shortName + "[" + getName() + "]"; } }
⏎ org/apache/commons/lang/enum/Enum.java
⇒ Using commons-lang3.jar in Java Programs
⇐ commons-lang-2.6.jar - Apache Commons Lang
2017-04-15, 18580👍, 0💬
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