    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.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     * @since 3.1
    051     */
    052    protected AbstractMapDecorator() {
    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        this.map = Objects.requireNonNull(map, "map");
    063    }
    064
    065    @Override
    066    public void clear() {
    067        decorated().clear();
    068    }
    069
    070    @Override
    071    public boolean containsKey(final Object key) {
    072        return decorated().containsKey(key);
    073    }
    074
    075    @Override
    076    public boolean containsValue(final Object value) {
    077        return decorated().containsValue(value);
    078    }
    079
    080    /**
    081     * Gets the map being decorated.
    082     *
    083     * @return the decorated map
    084     */
    085    protected Map<K, V> decorated() {
    086        return map;
    087    }
    088
    089    @Override
    090    public Set<Map.Entry<K, V>> entrySet() {
    091        return decorated().entrySet();
    092    }
    093
    094    @Override
    095    public boolean equals(final Object object) {
    096        if (object == this) {
    097            return true;
    098        }
    099        return decorated().equals(object);
    100    }
    101
    102    @Override
    103    public V get(final Object key) {
    104        return decorated().get(key);
    105    }
    106
    107    @Override
    108    public int hashCode() {
    109        return decorated().hashCode();
    110    }
    111
    112    @Override
    113    public boolean isEmpty() {
    114        return decorated().isEmpty();
    115    }
    116
    117    @Override
    118    public Set<K> keySet() {
    119        return decorated().keySet();
    120    }
    121
    122    @Override
    123    public V put(final K key, final V value) {
    124        return decorated().put(key, value);
    125    }
    126
    127    @Override
    128    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    129        decorated().putAll(mapToCopy);
    130    }
    131
    132    @Override
    133    public V remove(final Object key) {
    134        return decorated().remove(key);
    135    }
    136
    137    @Override
    138    public int size() {
    139        return decorated().size();
    140    }
    141
    142    @Override
    143    public String toString() {
    144        return decorated().toString();
    145    }
    146
    147    @Override
    148    public Collection<V> values() {
    149        return decorated().values();
    150    }
    151
    152}