    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.bidimap;
    018
    019import java.util.Map;
    020import java.util.Set;
    021
    022import org.apache.commons.collections4.OrderedBidiMap;
    023import org.apache.commons.collections4.OrderedMapIterator;
    024import org.apache.commons.collections4.Unmodifiable;
    025import org.apache.commons.collections4.iterators.UnmodifiableOrderedMapIterator;
    026import org.apache.commons.collections4.map.UnmodifiableEntrySet;
    027import org.apache.commons.collections4.set.UnmodifiableSet;
    028
    029/**
    030 * Decorates another {@link OrderedBidiMap} 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 UnmodifiableOrderedBidiMap<K, V>
    040        extends AbstractOrderedBidiMapDecorator<K, V> implements Unmodifiable {
    041
    042    /** The inverse unmodifiable map */
    043    private UnmodifiableOrderedBidiMap<V, K> inverse;
    044
    045    /**
    046     * Factory method to create an unmodifiable map.
    047     * <p>
    048     * If the map passed in is already unmodifiable, it is returned.
    049     *
    050     * @param <K> the key type
    051     * @param <V> the value type
    052     * @param map  the map to decorate, must not be null
    053     * @return an unmodifiable OrderedBidiMap
    054     * @throws NullPointerException if map is null
    055     * @since 4.0
    056     */
    057    public static <K, V> OrderedBidiMap<K, V> unmodifiableOrderedBidiMap(
    058            final OrderedBidiMap<? extends K, ? extends V> map) {
    059        if (map instanceof Unmodifiable) {
    060            @SuppressWarnings("unchecked") // safe to upcast
    061            final OrderedBidiMap<K, V> tmpMap = (OrderedBidiMap<K, V>) map;
    062            return tmpMap;
    063        }
    064        return new UnmodifiableOrderedBidiMap<>(map);
    065    }
    066
    067    //-----------------------------------------------------------------------
    068    /**
    069     * Constructor that wraps (not copies).
    070     *
    071     * @param map  the map to decorate, must not be null
    072     * @throws NullPointerException if map is null
    073     */
    074    @SuppressWarnings("unchecked") // safe to upcast
    075    private UnmodifiableOrderedBidiMap(final OrderedBidiMap<? extends K, ? extends V> map) {
    076        super((OrderedBidiMap<K, V>) map);
    077    }
    078
    079    //-----------------------------------------------------------------------
    080    @Override
    081    public void clear() {
    082        throw new UnsupportedOperationException();
    083    }
    084
    085    @Override
    086    public V put(final K key, final V value) {
    087        throw new UnsupportedOperationException();
    088    }
    089
    090    @Override
    091    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    092        throw new UnsupportedOperationException();
    093    }
    094
    095    @Override
    096    public V remove(final Object key) {
    097        throw new UnsupportedOperationException();
    098    }
    099
    100    @Override
    101    public Set<Map.Entry<K, V>> entrySet() {
    102        final Set<Map.Entry<K, V>> set = super.entrySet();
    103        return UnmodifiableEntrySet.unmodifiableEntrySet(set);
    104    }
    105
    106    @Override
    107    public Set<K> keySet() {
    108        final Set<K> set = super.keySet();
    109        return UnmodifiableSet.unmodifiableSet(set);
    110    }
    111
    112    @Override
    113    public Set<V> values() {
    114        final Set<V> set = super.values();
    115        return UnmodifiableSet.unmodifiableSet(set);
    116    }
    117
    118    //-----------------------------------------------------------------------
    119    @Override
    120    public K removeValue(final Object value) {
    121        throw new UnsupportedOperationException();
    122    }
    123
    124    @Override
    125    public OrderedBidiMap<V, K> inverseBidiMap() {
    126        return inverseOrderedBidiMap();
    127    }
    128
    129    //-----------------------------------------------------------------------
    130    @Override
    131    public OrderedMapIterator<K, V> mapIterator() {
    132        final OrderedMapIterator<K, V> it = decorated().mapIterator();
    133        return UnmodifiableOrderedMapIterator.unmodifiableOrderedMapIterator(it);
    134    }
    135
    136    /**
    137     * Gets an unmodifiable view of this map where the keys and values are reversed.
    138     *
    139     * @return an inverted unmodifiable bidirectional map
    140     */
    141    public OrderedBidiMap<V, K> inverseOrderedBidiMap() {
    142        if (inverse == null) {
    143            inverse = new UnmodifiableOrderedBidiMap<>(decorated().inverseBidiMap());
    144            inverse.inverse = this;
    145        }
    146        return inverse;
    147    }
    148
    149}