    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 2.0 (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    }