    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.map;
    018
    019import java.util.Collection;
    020import java.util.Map;
    021import java.util.Set;
    022
    023/**
    024 * Provides a base decorator that enables additional functionality to be added
    025 * to a Map via decoration.
    026 * <p>
    027 * Methods are forwarded directly to the decorated map.
    028 * <p>
    029 * This implementation does not perform any special processing with
    030 * {@link #entrySet()}, {@link #keySet()} or {@link #values()}. Instead
    031 * it simply returns the set/collection from the wrapped map. This may be
    032 * undesirable, for example if you are trying to write a validating
    033 * implementation it would provide a loophole around the validation.
    034 * But, you might want that loophole, so this class is kept simple.
    035 *
    036 * @param <K> the type of the keys in the map
    037 * @param <V> the type of the values in the map
    038 * @since 3.0
    039 */
    040public abstract class AbstractMapDecorator<K, V> extends AbstractIterableMap<K, V> {
    041
    042    /** The map to decorate */
    043    transient Map<K, V> map;
    044
    045    /**
    046     * Constructor only used in deserialization, do not use otherwise.
    047     * @since 3.1
    048     */
    049    protected AbstractMapDecorator() {
    050        super();
    051    }
    052
    053    /**
    054     * Constructor that wraps (not copies).
    055     *
    056     * @param map  the map to decorate, must not be null
    057     * @throws NullPointerException if the map is null
    058     */
    059    protected AbstractMapDecorator(final Map<K, V> map) {
    060        if (map == null) {
    061            throw new NullPointerException("Map must not be null.");
    062        }
    063        this.map = map;
    064    }
    065
    066    /**
    067     * Gets the map being decorated.
    068     *
    069     * @return the decorated map
    070     */
    071    protected Map<K, V> decorated() {
    072        return map;
    073    }
    074
    075    //-----------------------------------------------------------------------
    076    @Override
    077    public void clear() {
    078        decorated().clear();
    079    }
    080
    081    @Override
    082    public boolean containsKey(final Object key) {
    083        return decorated().containsKey(key);
    084    }
    085
    086    @Override
    087    public boolean containsValue(final Object value) {
    088        return decorated().containsValue(value);
    089    }
    090
    091    @Override
    092    public Set<Map.Entry<K, V>> entrySet() {
    093        return decorated().entrySet();
    094    }
    095
    096    @Override
    097    public V get(final Object key) {
    098        return decorated().get(key);
    099    }
    100
    101    @Override
    102    public boolean isEmpty() {
    103        return decorated().isEmpty();
    104    }
    105
    106    @Override
    107    public Set<K> keySet() {
    108        return decorated().keySet();
    109    }
    110
    111    @Override
    112    public V put(final K key, final V value) {
    113        return decorated().put(key, value);
    114    }
    115
    116    @Override
    117    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    118        decorated().putAll(mapToCopy);
    119    }
    120
    121    @Override
    122    public V remove(final Object key) {
    123        return decorated().remove(key);
    124    }
    125
    126    @Override
    127    public int size() {
    128        return decorated().size();
    129    }
    130
    131    @Override
    132    public Collection<V> values() {
    133        return decorated().values();
    134    }
    135
    136    @Override
    137    public boolean equals(final Object object) {
    138        if (object == this) {
    139            return true;
    140        }
    141        return decorated().equals(object);
    142    }
    143
    144    @Override
    145    public int hashCode() {
    146        return decorated().hashCode();
    147    }
    148
    149    @Override
    150    public String toString() {
    151        return decorated().toString();
    152    }
    153
    154}