AbstractMapDecorator


1   /*
2    *  Copyright 2003-2004 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.collections.map;
17  
18  import java.util.Collection  ;
19  import java.util.Map  ;
20  import java.util.Set  ;
21  
22  /**
23   * Provides a base decorator that enables additional functionality to be added
24   * to a Map via decoration.
25   * <p>
26   * Methods are forwarded directly to the decorated map.
27   * <p>
28   * This implementation does not perform any special processing with
29   * {@link #entrySet()}, {@link #keySet()} or {@link #values()}. Instead
30   * it simply returns the set/collection from the wrapped map. This may be
31   * undesirable, for example if you are trying to write a validating
32   * implementation it would provide a loophole around the validation.
33   * But, you might want that loophole, so this class is kept simple.
34   *
35   * @since Commons Collections 3.0
36   * @version $Revision: 1.5 $ $Date: 2004/04/02 21:02:54 $
37   * 
38   * @author Daniel Rall
39   * @author Stephen Colebourne
40   */
41  public abstract class AbstractMapDecorator implements Map   {
42  
43      /** The map to decorate */
44      protected transient Map   map;
45  
46      /**
47       * Constructor only used in deserialization, do not use otherwise.
48       * @since Commons Collections 3.1
49       */
50      protected AbstractMapDecorator() {
51          super();
52      }
53  
54      /**
55       * Constructor that wraps (not copies).
56       *
57       * @param map  the map to decorate, must not be null
58       * @throws IllegalArgumentException if the collection is null
59       */
60      public AbstractMapDecorator(Map   map) {
61          if (map == null) {
62              throw new IllegalArgumentException  ("Map must not be null");
63          }
64          this.map = map;
65      }
66  
67      /**
68       * Gets the map being decorated.
69       * 
70       * @return the decorated map
71       */
72      protected Map   getMap() {
73          return map;
74      }
75  
76      //-----------------------------------------------------------------------
77      public void clear() {
78          map.clear();
79      }
80  
81      public boolean containsKey(Object   key) {
82          return map.containsKey(key);
83      }
84  
85      public boolean containsValue(Object   value) {
86          return map.containsValue(value);
87      }
88  
89      public Set   entrySet() {
90          return map.entrySet();
91      }
92  
93      public Object   get(Object   key) {
94          return map.get(key);
95      }
96  
97      public boolean isEmpty() {
98          return map.isEmpty();
99      }
100 
101     public Set   keySet() {
102         return map.keySet();
103     }
104 
105     public Object   put(Object   key, Object   value) {
106         return map.put(key, value);
107     }
108 
109     public void putAll(Map   mapToCopy) {
110         map.putAll(mapToCopy);
111     }
112 
113     public Object   remove(Object   key) {
114         return map.remove(key);
115     }
116 
117     public int size() {
118         return map.size();
119     }
120 
121     public Collection   values() {
122         return map.values();
123     }
124    
125     public boolean equals(Object   object) {
126         if (object == this) {
127             return true;
128         }
129         return map.equals(object);
130     }
131 
132     public int hashCode() {
133         return map.hashCode();
134     }
135 
136     public String   toString() {
137         return map.toString();
138     }
139 
140 }
141
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