001    /*
002     * Copyright (C) 2007 The Guava Authors
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package com.google.common.collect;
018    
019    import com.google.common.annotations.GwtCompatible;
020    
021    import java.util.concurrent.ConcurrentMap;
022    
023    /**
024     * A concurrent map which forwards all its method calls to another concurrent
025     * map. Subclasses should override one or more methods to modify the behavior of
026     * the backing map as desired per the <a
027     * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
028     *
029     * @author Charles Fry
030     * @since 2 (imported from Google Collections Library)
031     */
032    @GwtCompatible
033    public abstract class ForwardingConcurrentMap<K, V> extends ForwardingMap<K, V>
034        implements ConcurrentMap<K, V> {
035    
036      /** Constructor for use by subclasses. */
037      protected ForwardingConcurrentMap() {}
038    
039      @Override protected abstract ConcurrentMap<K, V> delegate();
040    
041      @Override
042      public V putIfAbsent(K key, V value) {
043        return delegate().putIfAbsent(key, value);
044      }
045    
046      @Override
047      public boolean remove(Object key, Object value) {
048        return delegate().remove(key, value);
049      }
050    
051      @Override
052      public V replace(K key, V value) {
053        return delegate().replace(key, value);
054      }
055    
056      @Override
057      public boolean replace(K key, V oldValue, V newValue) {
058        return delegate().replace(key, oldValue, newValue);
059      }
060    
061    }