- /*
- * Copyright 2003-2004 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.apache.commons.collections.bidimap;
-
- import java.io.IOException;
- import java.io.ObjectInputStream;
- import java.io.ObjectOutputStream;
- import java.io.Serializable;
- import java.util.HashMap;
- import java.util.Map;
-
- import org.apache.commons.collections.BidiMap;
-
- /**
- * Implementation of <code>BidiMap</code> that uses two <code>HashMap</code> instances.
- * <p>
- * Two <code>HashMap</code> instances are used in this class.
- * This provides fast lookups at the expense of storing two sets of map entries.
- * Commons Collections would welcome the addition of a direct hash-based
- * implementation of the <code>BidiMap</code> interface.
- * <p>
- * NOTE: From Commons Collections 3.1, all subclasses will use <code>HashMap</code>
- * and the flawed <code>createMap</code> method is ignored.
- *
- * @since Commons Collections 3.0
- * @version $Id: DualHashBidiMap.java,v 1.7 2004/06/11 23:27:37 scolebourne Exp $
- *
- * @author Matthew Hawthorne
- * @author Stephen Colebourne
- */
- public class DualHashBidiMap
- extends AbstractDualBidiMap implements Serializable {
-
- /** Ensure serialization compatibility */
- private static final long serialVersionUID = 721969328361808L;
-
- /**
- * Creates an empty <code>HashBidiMap</code>.
- */
- public DualHashBidiMap() {
- super(new HashMap(), new HashMap());
- }
-
- /**
- * Constructs a <code>HashBidiMap</code> and copies the mappings from
- * specified <code>Map</code>.
- *
- * @param map the map whose mappings are to be placed in this map
- */
- public DualHashBidiMap(Map map) {
- super(new HashMap(), new HashMap());
- putAll(map);
- }
-
- /**
- * Constructs a <code>HashBidiMap</code> that decorates the specified maps.
- *
- * @param normalMap the normal direction map
- * @param reverseMap the reverse direction map
- * @param inverseBidiMap the inverse BidiMap
- */
- protected DualHashBidiMap(Map normalMap, Map reverseMap, BidiMap inverseBidiMap) {
- super(normalMap, reverseMap, inverseBidiMap);
- }
-
- /**
- * Creates a new instance of this object.
- *
- * @param normalMap the normal direction map
- * @param reverseMap the reverse direction map
- * @param inverseBidiMap the inverse BidiMap
- * @return new bidi map
- */
- protected BidiMap createBidiMap(Map normalMap, Map reverseMap, BidiMap inverseBidiMap) {
- return new DualHashBidiMap(normalMap, reverseMap, inverseBidiMap);
- }
-
- // Serialization
- //-----------------------------------------------------------------------
- private void writeObject(ObjectOutputStream out) throws IOException {
- out.defaultWriteObject();
- out.writeObject(maps[0]);
- }
-
- private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
- in.defaultReadObject();
- maps[0] = new HashMap();
- maps[1] = new HashMap();
- Map map = (Map) in.readObject();
- putAll(map);
- }
-
- }