001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one or more
003     *  contributor license agreements.  See the NOTICE file distributed with
004     *  this work for additional information regarding copyright ownership.
005     *  The ASF licenses this file to You under the Apache License, Version 2.0
006     *  (the "License"); you may not use this file except in compliance with
007     *  the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    package org.apache.commons.collections.set;
018    
019    import java.util.Comparator;
020    import java.util.Set;
021    import java.util.SortedSet;
022    
023    /**
024     * Decorates another <code>SortedSet</code> to provide additional behaviour.
025     * <p>
026     * Methods are forwarded directly to the decorated set.
027     *
028     * @since Commons Collections 3.0
029     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
030     * 
031     * @author Stephen Colebourne
032     */
033    public abstract class AbstractSortedSetDecorator extends AbstractSetDecorator implements SortedSet {
034    
035        /**
036         * Constructor only used in deserialization, do not use otherwise.
037         * @since Commons Collections 3.1
038         */
039        protected AbstractSortedSetDecorator() {
040            super();
041        }
042    
043        /**
044         * Constructor that wraps (not copies).
045         * 
046         * @param set  the set to decorate, must not be null
047         * @throws IllegalArgumentException if set is null
048         */
049        protected AbstractSortedSetDecorator(Set set) {
050            super(set);
051        }
052    
053        /**
054         * Gets the sorted set being decorated.
055         * 
056         * @return the decorated set
057         */
058        protected SortedSet getSortedSet() {
059            return (SortedSet) getCollection();
060        }
061        
062        //-----------------------------------------------------------------------
063        public SortedSet subSet(Object fromElement, Object toElement) {
064            return getSortedSet().subSet(fromElement, toElement);
065        }
066    
067        public SortedSet headSet(Object toElement) {
068            return getSortedSet().headSet(toElement);
069        }
070    
071        public SortedSet tailSet(Object fromElement) {
072            return getSortedSet().tailSet(fromElement);
073        }
074    
075        public Object first() {
076            return getSortedSet().first();
077        }
078    
079        public Object last() {
080            return getSortedSet().last();
081        }
082    
083        public Comparator comparator() {
084            return getSortedSet().comparator();
085        }
086    
087    }