1   /*
2    * Copyright (C) 2007 The Guava Authors
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  
17  package com.google.common.collect;
18  
19  import com.google.common.annotations.GwtCompatible;
20  
21  import java.util.concurrent.ConcurrentMap;
22  
23  /**
24   * A concurrent map which forwards all its method calls to another concurrent
25   * map. Subclasses should override one or more methods to modify the behavior of
26   * the backing map as desired per the <a
27   * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
28   *
29   * @author Charles Fry
30   * @since 2.0 (imported from Google Collections Library)
31   */
32  @GwtCompatible
33  public abstract class ForwardingConcurrentMap<K, V> extends ForwardingMap<K, V>
34      implements ConcurrentMap<K, V> {
35  
36    /** Constructor for use by subclasses. */
37    protected ForwardingConcurrentMap() {}
38  
39    @Override protected abstract ConcurrentMap<K, V> delegate();
40  
41    @Override
42    public V putIfAbsent(K key, V value) {
43      return delegate().putIfAbsent(key, value);
44    }
45  
46    @Override
47    public boolean remove(Object key, Object value) {
48      return delegate().remove(key, value);
49    }
50  
51    @Override
52    public V replace(K key, V value) {
53      return delegate().replace(key, value);
54    }
55  
56    @Override
57    public boolean replace(K key, V oldValue, V newValue) {
58      return delegate().replace(key, oldValue, newValue);
59    }
60  
61  }