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}