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.map;
018    
019    import java.util.Comparator;
020    import java.util.SortedMap;
021    
022    /** 
023     * Provides a base decorator that enables additional functionality to be added
024     * to a Map via decoration.
025     * <p>
026     * Methods are forwarded directly to the decorated map.
027     * <p>
028     * This implementation does not perform any special processing with the map views.
029     * Instead it simply returns the set/collection from the wrapped map. This may be
030     * undesirable, for example if you are trying to write a validating implementation
031     * it would provide a loophole around the validation.
032     * But, you might want that loophole, so this class is kept simple.
033     *
034     * @since Commons Collections 3.0
035     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
036     * 
037     * @author Stephen Colebourne
038     */
039    public abstract class AbstractSortedMapDecorator
040            extends AbstractMapDecorator implements SortedMap {
041    
042        /**
043         * Constructor only used in deserialization, do not use otherwise.
044         * @since Commons Collections 3.1
045         */
046        protected AbstractSortedMapDecorator() {
047            super();
048        }
049    
050        /**
051         * Constructor that wraps (not copies).
052         *
053         * @param map  the map to decorate, must not be null
054         * @throws IllegalArgumentException if the collection is null
055         */
056        public AbstractSortedMapDecorator(SortedMap map) {
057            super(map);
058        }
059    
060        /**
061         * Gets the map being decorated.
062         * 
063         * @return the decorated map
064         */
065        protected SortedMap getSortedMap() {
066            return (SortedMap) map;
067        }
068    
069        //-----------------------------------------------------------------------
070        public Comparator comparator() {
071            return getSortedMap().comparator();
072        }
073    
074        public Object firstKey() {
075            return getSortedMap().firstKey();
076        }
077    
078        public SortedMap headMap(Object toKey) {
079            return getSortedMap().headMap(toKey);
080        }
081    
082        public Object lastKey() {
083            return getSortedMap().lastKey();
084        }
085    
086        public SortedMap subMap(Object fromKey, Object toKey) {
087            return getSortedMap().subMap(fromKey, toKey);
088        }
089    
090        public SortedMap tailMap(Object fromKey) {
091            return getSortedMap().tailMap(fromKey);
092        }
093    
094    }