/*

  * $Id: MapEntry.java 1049711 2010-12-15 21:12:00Z apetrelli $

  *

  * 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.tiles.request.collection;

 import java.util.Map;

 /**

  * <p>Map.Entry implementation that can be constructed to either be read-only

  * or not.</p>

  *

  * @version $Rev: 1049711 $ $Date: 2010-12-16 08:12:00 +1100 (Thu, 16 Dec 2010) $

  * @param <K> The key type.

  * @param <V> The value type.

  */

 public class MapEntry<K, V> implements Map.Entry<K, V> {

     /**

      * <p>The entry key.</p>

      */

     private K key;

     /**

      * <p>The entry value.</p>

      */

     private V value;

     /**

      * <p>Whether the entry can be modified.</p>

      */

     private boolean modifiable = false;

     /**

      * <p>Creates a map entry that can either allow modifications or not.</p>

      *

      * @param key        The entry key

      * @param value      The entry value

      * @param modifiable Whether the entry should allow modification or not

      */

     public MapEntry(K key, V value, boolean modifiable) {

         this.key = key;

         this.value = value;

         this.modifiable = modifiable;

     }

     /**

      * <p>Gets the entry key.</p>

      *

      * @return The entry key

      */

     public K getKey() {

         return key;

     }

     /**

      * <p>Gets the entry value.</p>

      *

      * @return The entry key

      */

     public V getValue() {

         return value;

     }

     /**

      * <p>Sets the entry value if the entry can be modified.</p>

      *

      * @param val The new value

      * @return The old entry value

      * @throws UnsupportedOperationException If the entry cannot be modified

      */

     public V setValue(V val) {

         if (modifiable) {

             V oldVal = this.value;

             this.value = val;

             return oldVal;

         }

         throw new UnsupportedOperationException("The map entry is not modifiable");

     }

     /**

      * <p>Determines if this entry is equal to the passed object.</p>

      *

      * @param o The object to test

      * @return True if equal, else false

      */

     @Override

     @SuppressWarnings("unchecked")

     public boolean equals(Object o) {

         if (o != null && o instanceof Map.Entry) {

             Map.Entry<K, V> entry = (Map.Entry<K, V>) o;

             return (this.getKey() == null ? entry.getKey() == null : this

                     .getKey().equals(entry.getKey()))

                     && (this.getValue() == null ? entry.getValue() == null

                             : this.getValue().equals(entry.getValue()));

         }

         return false;

     }

     /**

      * <p>Returns the hashcode for this entry.</p>

      *

      * @return The and'ed hashcode of the key and value

      */

     @Override

     public int hashCode() {

         return (this.getKey() == null ? 0 : this.getKey().hashCode())

             ^ (this.getValue() == null ? 0 : this.getValue().hashCode());

     }

 }