    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 * <p>
    030 * This implementation does not perform any special processing with
    031 * {@link #entrySet()}, {@link #keySet()} or {@link #values()}. Instead
    032 * it simply returns the set/collection from the wrapped map. This may be
    033 * undesirable, for example if you are trying to write a validating
    034 * implementation it would provide a loophole around the validation.
    035 * But, you might want that loophole, so this class is kept simple.
    036 * </p>
    037 *
    038 * @param <K> the type of the keys in the map
    039 * @param <V> the type of the values in the map
    040 * @since 3.0
    041 */
    042public abstract class AbstractMapDecorator<K, V> extends AbstractIterableMap<K, V> {
    043
    044    /** The map to decorate */
    045    transient Map<K, V> map;
    046
    047    /**
    048     * Constructor only used in deserialization, do not use otherwise.
    049     * @since 3.1
    050     */
    051    protected AbstractMapDecorator() {
    052        super();
    053    }
    054
    055    /**
    056     * Constructor that wraps (not copies).
    057     *
    058     * @param map  the map to decorate, must not be null
    059     * @throws NullPointerException if the map is null
    060     */
    061    protected AbstractMapDecorator(final Map<K, V> map) {
    062        if (map == null) {
    063            throw new NullPointerException("Map must not be null.");
    064        }
    065        this.map = map;
    066    }
    067
    068    /**
    069     * Gets the map being decorated.
    070     *
    071     * @return the decorated map
    072     */
    073    protected Map<K, V> decorated() {
    074        return map;
    075    }
    076
    077    //-----------------------------------------------------------------------
    078    @Override
    079    public void clear() {
    080        decorated().clear();
    081    }
    082
    083    @Override
    084    public boolean containsKey(final Object key) {
    085        return decorated().containsKey(key);
    086    }
    087
    088    @Override
    089    public boolean containsValue(final Object value) {
    090        return decorated().containsValue(value);
    091    }
    092
    093    @Override
    094    public Set<Map.Entry<K, V>> entrySet() {
    095        return decorated().entrySet();
    096    }
    097
    098    @Override
    099    public V get(final Object key) {
    100        return decorated().get(key);
    101    }
    102
    103    @Override
    104    public boolean isEmpty() {
    105        return decorated().isEmpty();
    106    }
    107
    108    @Override
    109    public Set<K> keySet() {
    110        return decorated().keySet();
    111    }
    112
    113    @Override
    114    public V put(final K key, final V value) {
    115        return decorated().put(key, value);
    116    }
    117
    118    @Override
    119    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    120        decorated().putAll(mapToCopy);
    121    }
    122
    123    @Override
    124    public V remove(final Object key) {
    125        return decorated().remove(key);
    126    }
    127
    128    @Override
    129    public int size() {
    130        return decorated().size();
    131    }
    132
    133    @Override
    134    public Collection<V> values() {
    135        return decorated().values();
    136    }
    137
    138    @Override
    139    public boolean equals(final Object object) {
    140        if (object == this) {
    141            return true;
    142        }
    143        return decorated().equals(object);
    144    }
    145
    146    @Override
    147    public int hashCode() {
    148        return decorated().hashCode();
    149    }
    150
    151    @Override
    152    public String toString() {
    153        return decorated().toString();
    154    }
    155
    156}