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