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; 018 019 /** 020 * Defines a map that allows bidirectional lookup between key and values 021 * and retains and provides access to an ordering. 022 * <p> 023 * Implementations should allow a value to be looked up from a key and 024 * a key to be looked up from a value with equal performance. 025 * 026 * @since Commons Collections 3.0 027 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 028 * 029 * @author Stephen Colebourne 030 */ 031 public interface OrderedBidiMap extends BidiMap, OrderedMap { 032 033 /** 034 * Gets a view of this map where the keys and values are reversed. 035 * <p> 036 * Changes to one map will be visible in the other and vice versa. 037 * This enables both directions of the map to be accessed equally. 038 * <p> 039 * Implementations should seek to avoid creating a new object every time this 040 * method is called. See <code>AbstractMap.values()</code> etc. Calling this 041 * method on the inverse map should return the original. 042 * <p> 043 * Implementations must return an <code>OrderedBidiMap</code> instance, 044 * usually by forwarding to <code>inverseOrderedBidiMap()</code>. 045 * 046 * @return an inverted bidirectional map 047 */ 048 public BidiMap inverseBidiMap(); 049 050 /** 051 * Gets a view of this map where the keys and values are reversed. 052 * <p> 053 * Changes to one map will be visible in the other and vice versa. 054 * This enables both directions of the map to be accessed equally. 055 * <p> 056 * Implementations should seek to avoid creating a new object every time this 057 * method is called. See <code>AbstractMap.values()</code> etc. Calling this 058 * method on the inverse map should return the original. 059 * 060 * @return an inverted bidirectional map 061 */ 062 public OrderedBidiMap inverseOrderedBidiMap(); 063 064 }