    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.bidimap;
    018
    019import java.util.Map;
    020import java.util.Set;
    021
    022import org.apache.commons.collections4.BidiMap;
    023import org.apache.commons.collections4.MapIterator;
    024import org.apache.commons.collections4.Unmodifiable;
    025import org.apache.commons.collections4.iterators.UnmodifiableMapIterator;
    026import org.apache.commons.collections4.map.UnmodifiableEntrySet;
    027import org.apache.commons.collections4.set.UnmodifiableSet;
    028
    029/**
    030 * Decorates another {@link BidiMap} to ensure it can't be altered.
    031 * <p>
    032 * Attempts to modify it will result in an UnsupportedOperationException.
    033 * </p>
    034 *
    035 * @param <K> The type of the keys in this map
    036 * @param <V> The type of the values in this map
    037 * @since 3.0
    038 */
    039public final class UnmodifiableBidiMap<K, V>
    040        extends AbstractBidiMapDecorator<K, V> implements Unmodifiable {
    041
    042    /**
    043     * Factory method to create an unmodifiable map.
    044     * <p>
    045     * If the map passed in is already unmodifiable, it is returned.
    046     *
    047     * @param <K> The key type
    048     * @param <V> The value type
    049     * @param map  The map to decorate, must not be null
    050     * @return An unmodifiable BidiMap
    051     * @throws NullPointerException if map is null
    052     * @since 4.0
    053     */
    054    public static <K, V> BidiMap<K, V> unmodifiableBidiMap(final BidiMap<? extends K, ? extends V> map) {
    055        if (map instanceof Unmodifiable) {
    056            @SuppressWarnings("unchecked") // safe to upcast
    057            final BidiMap<K, V> tmpMap = (BidiMap<K, V>) map;
    058            return tmpMap;
    059        }
    060        return new UnmodifiableBidiMap<>(map);
    061    }
    062
    063    /** The inverse unmodifiable map */
    064    private UnmodifiableBidiMap<V, K> inverse;
    065
    066    /**
    067     * Constructor that wraps (not copies).
    068     *
    069     * @param map  The map to decorate, must not be null
    070     * @throws NullPointerException if map is null
    071     */
    072    @SuppressWarnings("unchecked") // safe to upcast
    073    private UnmodifiableBidiMap(final BidiMap<? extends K, ? extends V> map) {
    074        super((BidiMap<K, V>) map);
    075    }
    076
    077    /**
    078     * Always throws {@link UnsupportedOperationException}.
    079     *
    080     * @throws UnsupportedOperationException Always thrown.
    081     */
    082    @Override
    083    public void clear() {
    084        throw new UnsupportedOperationException();
    085    }
    086
    087    @Override
    088    public Set<Map.Entry<K, V>> entrySet() {
    089        final Set<Map.Entry<K, V>> set = super.entrySet();
    090        return UnmodifiableEntrySet.unmodifiableEntrySet(set);
    091    }
    092
    093    @Override
    094    public synchronized BidiMap<V, K> inverseBidiMap() {
    095        if (inverse == null) {
    096            inverse = new UnmodifiableBidiMap<>(decorated().inverseBidiMap());
    097            inverse.inverse = this;
    098        }
    099        return inverse;
    100    }
    101
    102    @Override
    103    public Set<K> keySet() {
    104        final Set<K> set = super.keySet();
    105        return UnmodifiableSet.unmodifiableSet(set);
    106    }
    107
    108    @Override
    109    public MapIterator<K, V> mapIterator() {
    110        final MapIterator<K, V> it = decorated().mapIterator();
    111        return UnmodifiableMapIterator.unmodifiableMapIterator(it);
    112    }
    113
    114    /**
    115     * Always throws {@link UnsupportedOperationException}.
    116     *
    117     * @param key Ignored.
    118     * @param value Ignored.
    119     * @throws UnsupportedOperationException Always thrown.
    120     */
    121    @Override
    122    public V put(final K key, final V value) {
    123        throw new UnsupportedOperationException();
    124    }
    125
    126    /**
    127     * Always throws {@link UnsupportedOperationException}.
    128     *
    129     * @param mapToCopy Ignored.
    130     * @throws UnsupportedOperationException Always thrown.
    131     */
    132    @Override
    133    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    134        throw new UnsupportedOperationException();
    135    }
    136
    137    /**
    138     * Always throws {@link UnsupportedOperationException}.
    139     *
    140     * @param key Ignored.
    141     * @throws UnsupportedOperationException Always thrown.
    142     */
    143    @Override
    144    public V remove(final Object key) {
    145        throw new UnsupportedOperationException();
    146    }
    147
    148    /**
    149     * Always throws {@link UnsupportedOperationException}.
    150     *
    151     * @param value Ignored.
    152     * @throws UnsupportedOperationException Always thrown.
    153     */
    154    @Override
    155    public K removeValue(final Object value) {
    156        throw new UnsupportedOperationException();
    157    }
    158
    159    @Override
    160    public Set<V> values() {
    161        return UnmodifiableSet.unmodifiableSet(super.values());
    162    }
    163
    164}