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.SortedSet;
023    
024    /**
025     * A sorted set which forwards all its method calls to another sorted set.
026     * Subclasses should override one or more methods to modify the behavior of the
027     * backing sorted set 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 ForwardingSortedSet<E> extends ForwardingSet<E>
035        implements SortedSet<E> {
036    
037      /** Constructor for use by subclasses. */
038      protected ForwardingSortedSet() {}
039    
040      @Override protected abstract SortedSet<E> delegate();
041    
042      public Comparator<? super E> comparator() {
043        return delegate().comparator();
044      }
045    
046      public E first() {
047        return delegate().first();
048      }
049    
050      public SortedSet<E> headSet(E toElement) {
051        return delegate().headSet(toElement);
052      }
053    
054      public E last() {
055        return delegate().last();
056      }
057    
058      public SortedSet<E> subSet(E fromElement, E toElement) {
059        return delegate().subSet(fromElement, toElement);
060      }
061    
062      public SortedSet<E> tailSet(E fromElement) {
063        return delegate().tailSet(fromElement);
064      }
065    }