src/java/org/apache/commons/collections/map/AbstractOrderedMapDecorator.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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 org.apache.commons.collections.MapIterator;
import org.apache.commons.collections.OrderedMap;
import org.apache.commons.collections.OrderedMapIterator;

/** 
 * Provides a base decorator that enables additional functionality to be added
 * to an OrderedMap via decoration.
 * <p>
 * Methods are forwarded directly to the decorated map.
 * <p>
 * This implementation does not perform any special processing with the map views.
 * 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 $Revision$ $Date$
 * 
 * @author Stephen Colebourne
 */
public abstract class AbstractOrderedMapDecorator
        extends AbstractMapDecorator implements OrderedMap {

    /**
     * Constructor only used in deserialization, do not use otherwise.
     * @since Commons Collections 3.1
     */
    protected AbstractOrderedMapDecorator() {
        super();
    }

    /**
     * Constructor that wraps (not copies).
     *
     * @param map  the map to decorate, must not be null
     * @throws IllegalArgumentException if the collection is null
     */
    public AbstractOrderedMapDecorator(OrderedMap map) {
        super(map);
    }

    /**
     * Gets the map being decorated.
     * 
     * @return the decorated map
     */
    protected OrderedMap getOrderedMap() {
        return (OrderedMap) map;
    }

    //-----------------------------------------------------------------------
    public Object firstKey() {
        return getOrderedMap().firstKey();
    }

    public Object lastKey() {
        return getOrderedMap().lastKey();
    }

    public Object nextKey(Object key) {
        return getOrderedMap().nextKey(key);
    }

    public Object previousKey(Object key) {
        return getOrderedMap().previousKey(key);
    }

    public MapIterator mapIterator() {
        return getOrderedMap().mapIterator();
    }

    public OrderedMapIterator orderedMapIterator() {
        return getOrderedMap().orderedMapIterator();
    }

}