code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.lang.enum;
  
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.commons.lang.ClassUtils;
  
  /**
   * <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(JavaVersionEnum 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>
   *
   * @deprecated Replaced by {@link org.apache.commons.lang.enums.ValuedEnum org.apache.commons.lang.enums.ValuedEnum}
   *          and will be removed in version 3.0. All classes in this package are deprecated and repackaged to 
   *          {@link org.apache.commons.lang.enums} since <code>enum</code> is a Java 1.5 keyword. 
   * @see org.apache.commons.lang.enums.ValuedEnum
   * @author Apache Avalon project
   * @author Stephen Colebourne
   * @since 1.0
   * @version $Id: ValuedEnum.java 441929 2006-09-10 08:04:17Z bayard $
   */
  public abstract class ValuedEnum extends Enum {
      
      /**
       * Required for serialization support. Lang version 1.0.1 serial compatibility.
       * 
       * @see java.io.Serializable
       */
      private static final long serialVersionUID = -7129650521543789085L;
      
      /**
       * 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 enumeration = (ValuedEnum) it.next();
              if (enumeration.getValue() == value) {
                  return enumeration;
              }
          }
          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>
       *
       * @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() {
          if (iToString == null) {
              String shortName = ClassUtils.getShortClassName(getEnumClass());
              iToString = shortName + "[" + getName() + "=" + getValue() + "]";
          }
          return iToString;
      }
  }
  