1// GenericsNote: Converted.
2/*
3 *  Copyright 2003-2004 The Apache Software Foundation
4 *
5 *  Licensed under the Apache License, Version 2.0 (the "License");
6 *  you may not use this file except in compliance with the License.
7 *  You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 */
17package org.jivesoftware.smack.util.collections;
18
19import java.util.Map;
20
21/**
22 * Abstract Pair class to assist with creating correct Map Entry implementations.
23 *
24 * @author James Strachan
25 * @author Michael A. Smith
26 * @author Neil O'Toole
27 * @author Matt Hall, John Watkinson, Stephen Colebourne
28 * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $
29 * @since Commons Collections 3.0
30 */
31public abstract class AbstractMapEntry <K,V> extends AbstractKeyValue<K, V> implements Map.Entry<K, V> {
32
33    /**
34     * Constructs a new entry with the given key and given value.
35     *
36     * @param key   the key for the entry, may be null
37     * @param value the value for the entry, may be null
38     */
39    protected AbstractMapEntry(K key, V value) {
40        super(key, value);
41    }
42
43    // Map.Entry interface
44    //-------------------------------------------------------------------------
45    /**
46     * Sets the value stored in this Map Entry.
47     * <p/>
48     * This Map Entry is not connected to a Map, so only the local data is changed.
49     *
50     * @param value the new value
51     * @return the previous value
52     */
53    public V setValue(V value) {
54        V answer = this.value;
55        this.value = value;
56        return answer;
57    }
58
59    /**
60     * Compares this Map Entry with another Map Entry.
61     * <p/>
62     * Implemented per API documentation of {@link java.util.Map.Entry#equals(Object)}
63     *
64     * @param obj the object to compare to
65     * @return true if equal key and value
66     */
67    public boolean equals(Object obj) {
68        if (obj == this) {
69            return true;
70        }
71        if (obj instanceof Map.Entry == false) {
72            return false;
73        }
74        Map.Entry other = (Map.Entry) obj;
75        return (getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) && (getValue() == null ? other.getValue() == null : getValue().equals(other.getValue()));
76    }
77
78    /**
79     * Gets a hashCode compatible with the equals method.
80     * <p/>
81     * Implemented per API documentation of {@link java.util.Map.Entry#hashCode()}
82     *
83     * @return a suitable hash code
84     */
85    public int hashCode() {
86        return (getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode());
87    }
88
89}
90