001    /*
002     * Copyright (C) 2007 Google Inc.
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.Comparator;
022    import java.util.SortedMap;
023    
024    /**
025     * A sorted map which forwards all its method calls to another sorted map.
026     * Subclasses should override one or more methods to modify the behavior of
027     * the backing sorted map as desired per the <a
028     * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
029     *
030     * @author Mike Bostock
031     * @since 2 (imported from Google Collections Library)
032     */
033    @GwtCompatible
034    public abstract class ForwardingSortedMap<K, V> extends ForwardingMap<K, V>
035        implements SortedMap<K, V> {
036    
037      /** Constructor for use by subclasses. */
038      protected ForwardingSortedMap() {}
039    
040      @Override protected abstract SortedMap<K, V> delegate();
041    
042      public Comparator<? super K> comparator() {
043        return delegate().comparator();
044      }
045    
046      public K firstKey() {
047        return delegate().firstKey();
048      }
049    
050      public SortedMap<K, V> headMap(K toKey) {
051        return delegate().headMap(toKey);
052      }
053    
054      public K lastKey() {
055        return delegate().lastKey();
056      }
057    
058      public SortedMap<K, V> subMap(K fromKey, K toKey) {
059        return delegate().subMap(fromKey, toKey);
060      }
061    
062      public SortedMap<K, V> tailMap(K fromKey) {
063        return delegate().tailMap(fromKey);
064      }
065    }