1 /*
2 * $Id: MapEntry.java 1049711 2010-12-15 21:12:00Z apetrelli $
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21 package org.apache.tiles.request.collection;
22
23
24 import java.util.Map;
25
26
27 /**
28 * <p>Map.Entry implementation that can be constructed to either be read-only
29 * or not.</p>
30 *
31 * @version $Rev: 1049711 $ $Date: 2010-12-16 08:12:00 +1100 (Thu, 16 Dec 2010) $
32 * @param <K> The key type.
33 * @param <V> The value type.
34 */
35
36 public class MapEntry<K, V> implements Map.Entry<K, V> {
37
38
39 /**
40 * <p>The entry key.</p>
41 */
42 private K key;
43
44 /**
45 * <p>The entry value.</p>
46 */
47 private V value;
48
49 /**
50 * <p>Whether the entry can be modified.</p>
51 */
52 private boolean modifiable = false;
53
54
55 /**
56 * <p>Creates a map entry that can either allow modifications or not.</p>
57 *
58 * @param key The entry key
59 * @param value The entry value
60 * @param modifiable Whether the entry should allow modification or not
61 */
62 public MapEntry(K key, V value, boolean modifiable) {
63 this.key = key;
64 this.value = value;
65 this.modifiable = modifiable;
66 }
67
68
69 /**
70 * <p>Gets the entry key.</p>
71 *
72 * @return The entry key
73 */
74 public K getKey() {
75 return key;
76 }
77
78
79 /**
80 * <p>Gets the entry value.</p>
81 *
82 * @return The entry key
83 */
84 public V getValue() {
85 return value;
86 }
87
88
89 /**
90 * <p>Sets the entry value if the entry can be modified.</p>
91 *
92 * @param val The new value
93 * @return The old entry value
94 * @throws UnsupportedOperationException If the entry cannot be modified
95 */
96 public V setValue(V val) {
97 if (modifiable) {
98 V oldVal = this.value;
99 this.value = val;
100 return oldVal;
101 }
102 throw new UnsupportedOperationException("The map entry is not modifiable");
103 }
104
105
106 /**
107 * <p>Determines if this entry is equal to the passed object.</p>
108 *
109 * @param o The object to test
110 * @return True if equal, else false
111 */
112 @Override
113 @SuppressWarnings("unchecked")
114 public boolean equals(Object o) {
115 if (o != null && o instanceof Map.Entry) {
116 Map.Entry<K, V> entry = (Map.Entry<K, V>) o;
117 return (this.getKey() == null ? entry.getKey() == null : this
118 .getKey().equals(entry.getKey()))
119 && (this.getValue() == null ? entry.getValue() == null
120 : this.getValue().equals(entry.getValue()));
121 }
122 return false;
123 }
124
125
126 /**
127 * <p>Returns the hashcode for this entry.</p>
128 *
129 * @return The and'ed hashcode of the key and value
130 */
131 @Override
132 public int hashCode() {
133 return (this.getKey() == null ? 0 : this.getKey().hashCode())
134 ^ (this.getValue() == null ? 0 : this.getValue().hashCode());
135 }
136 }