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Java > Open Source Codes > org > apache > commons > chain > web > MapEntry


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.chain.web;
17
18
19 import java.util.Map JavaDoc;
20
21
22 /**
23  * <p>Map.Entry implementation that can be constructed to either be read-only
24  * or not.</p>
25  *
26  * @version $Revision: 1.3 $ $Date: 2004/11/30 05:52:23 $
27  */
28
29 public class MapEntry implements Map.Entry JavaDoc {
30
31
32     /**
33      * <p>The entry key.</p>
34      */
35     private Object JavaDoc key;
36
37     /**
38      * <p>The entry value.</p>
39      */
40     private Object JavaDoc value;
41
42     /**
43      * <p>Whether the entry can be modified.</p>
44      */
45     private boolean modifiable = false;
46
47
48     /**
49      * <p>Creates a map entry that can either allow modifications or not.</p>
50      *
51      * @param key The entry key
52      * @param value The entry value
53      * @param modifiable Whether the entry should allow modification or not
54      */
55     public MapEntry(Object JavaDoc key, Object JavaDoc value, boolean modifiable) {
56         this.key = key;
57         this.value = value;
58         this.modifiable = modifiable;
59     }
60
61
62     /**
63      * <p>Gets the entry key.</p>
64      *
65      * @return The entry key
66      */
67     public Object JavaDoc getKey() {
68         return key;
69     }
70
71
72     /**
73      * <p>Gets the entry value.</p>
74      *
75      * @return The entry key
76      */
77     public Object JavaDoc getValue() {
78         return value;
79     }
80
81
82     /**
83      * <p>Sets the entry value if the entry can be modified.</p>
84      *
85      * @param val The new value
86      * @return The old entry value
87      * @throws UnsupportedOperationException If the entry cannot be modified
88      */
89     public Object JavaDoc setValue(Object JavaDoc val) {
90         if (modifiable) {
91             Object JavaDoc oldVal = this.value;
92             this.value = val;
93             return oldVal;
94         } else {
95             throw new UnsupportedOperationException JavaDoc();
96         }
97     }
98
99
100     /**
101      * <p>Determines if this entry is equal to the passed object.</p>
102      *
103      * @param o The object to test
104      * @return True if equal, else false
105      */
106     public boolean equals(Object JavaDoc o) {
107         if (o != null && o instanceof Map.Entry JavaDoc) {
108             Map.Entry JavaDoc entry = (Map.Entry JavaDoc)o;
109             return (this.getKey() == null ?
110                     entry.getKey() == null : this.getKey().equals(entry.getKey())) &&
111                    (this.getValue() == null ?
112                     entry.getValue() == null : this.getValue().equals(entry.getValue()));
113         }
114         return false;
115     }
116
117
118     /**
119      * <p>Returns the hashcode for this entry.</p>
120      *
121      * @return The and'ed hashcode of the key and value
122      */
123     public int hashCode() {
124         return (this.getKey() == null ? 0 : this.getKey().hashCode()) ^
125                (this.getValue() == null ? 0 : this.getValue().hashCode());
126     }
127 }
128
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