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 */
017package org.apache.commons.collections4.keyvalue;
018
019import java.util.Map;
020
021import org.apache.commons.collections4.KeyValue;
022
023/**
024 * Provides a base decorator that allows additional functionality to be
025 * added to a {@link java.util.Map.Entry Map.Entry}.
026 *
027 * @since 3.0
028 */
029public abstract class AbstractMapEntryDecorator<K, V> implements Map.Entry<K, V>, KeyValue<K, V> {
030
031    /** The <code>Map.Entry</code> to decorate */
032    private final Map.Entry<K, V> entry;
033
034    /**
035     * Constructor that wraps (not copies).
036     *
037     * @param entry  the <code>Map.Entry</code> to decorate, must not be null
038     * @throws NullPointerException if the collection is null
039     */
040    public AbstractMapEntryDecorator(final Map.Entry<K, V> entry) {
041        if (entry == null) {
042            throw new NullPointerException("Map Entry must not be null.");
043        }
044        this.entry = entry;
045    }
046
047    /**
048     * Gets the map being decorated.
049     *
050     * @return the decorated map
051     */
052    protected Map.Entry<K, V> getMapEntry() {
053        return entry;
054    }
055
056    //-----------------------------------------------------------------------
057
058    @Override
059    public K getKey() {
060        return entry.getKey();
061    }
062
063    @Override
064    public V getValue() {
065        return entry.getValue();
066    }
067
068    @Override
069    public V setValue(final V object) {
070        return entry.setValue(object);
071    }
072
073    @Override
074    public boolean equals(final Object object) {
075        if (object == this) {
076            return true;
077        }
078        return entry.equals(object);
079    }
080
081    @Override
082    public int hashCode() {
083        return entry.hashCode();
084    }
085
086    @Override
087    public String toString() {
088        return entry.toString();
089    }
090
091}