Java tutorial
/* * 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.map; import java.util.Collection; import java.util.Map; import java.util.Set; /** * Provides a base decorator that enables additional functionality to be added * to a Map via decoration. * <p> * Methods are forwarded directly to the decorated map. * <p> * This implementation does not perform any special processing with * {@link #entrySet()}, {@link #keySet()} or {@link #values()}. Instead * it simply returns the set/collection from the wrapped map. This may be * undesirable, for example if you are trying to write a validating * implementation it would provide a loophole around the validation. * But, you might want that loophole, so this class is kept simple. * * @since Commons Collections 3.0 * @version $Revision: 1.5 $ $Date: 2004/04/02 21:02:54 $ * * @author Daniel Rall * @author Stephen Colebourne */ public abstract class AbstractMapDecorator implements Map { /** The map to decorate */ protected transient Map map; /** * Constructor only used in deserialization, do not use otherwise. * @since Commons Collections 3.1 */ protected AbstractMapDecorator() { super(); } /** * Constructor that wraps (not copies). * * @param map the map to decorate, must not be null * @throws IllegalArgumentException if the collection is null */ public AbstractMapDecorator(Map map) { if (map == null) { throw new IllegalArgumentException("Map must not be null"); } this.map = map; } /** * Gets the map being decorated. * * @return the decorated map */ protected Map getMap() { return map; } //----------------------------------------------------------------------- public void clear() { map.clear(); } public boolean containsKey(Object key) { return map.containsKey(key); } public boolean containsValue(Object value) { return map.containsValue(value); } public Set entrySet() { return map.entrySet(); } public Object get(Object key) { return map.get(key); } public boolean isEmpty() { return map.isEmpty(); } public Set keySet() { return map.keySet(); } public Object put(Object key, Object value) { return map.put(key, value); } public void putAll(Map mapToCopy) { map.putAll(mapToCopy); } public Object remove(Object key) { return map.remove(key); } public int size() { return map.size(); } public Collection values() { return map.values(); } public boolean equals(Object object) { if (object == this) { return true; } return map.equals(object); } public int hashCode() { return map.hashCode(); } public String toString() { return map.toString(); } }