    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.trie;
    018
    019import java.io.Serializable;
    020import java.util.Collection;
    021import java.util.Collections;
    022import java.util.Comparator;
    023import java.util.Map;
    024import java.util.Objects;
    025import java.util.Set;
    026import java.util.SortedMap;
    027
    028import org.apache.commons.collections4.OrderedMapIterator;
    029import org.apache.commons.collections4.Trie;
    030import org.apache.commons.collections4.Unmodifiable;
    031import org.apache.commons.collections4.iterators.UnmodifiableOrderedMapIterator;
    032import org.apache.commons.collections4.map.UnmodifiableEntrySet;
    033
    034/**
    035 * An unmodifiable {@link Trie}.
    036 *
    037 * @param <K> The type of the keys in this map
    038 * @param <V> The type of the values in this map
    039 * @since 4.0
    040 */
    041public class UnmodifiableTrie<K, V> implements Trie<K, V>, Serializable, Unmodifiable {
    042
    043    /** Serialization version */
    044    private static final long serialVersionUID = -7156426030315945159L;
    045
    046    /**
    047     * Factory method to create an unmodifiable trie.
    048     *
    049     * @param <K>  the key type
    050     * @param <V>  the value type
    051     * @param trie  The trie to decorate, must not be null
    052     * @return A new unmodifiable trie
    053     * @throws NullPointerException if trie is null
    054     */
    055    public static <K, V> Trie<K, V> unmodifiableTrie(final Trie<K, ? extends V> trie) {
    056        if (trie instanceof Unmodifiable) {
    057            @SuppressWarnings("unchecked") // safe to upcast
    058            final Trie<K, V> tmpTrie = (Trie<K, V>) trie;
    059            return tmpTrie;
    060        }
    061        return new UnmodifiableTrie<>(trie);
    062    }
    063
    064    /**
    065     * The delegate Trie.
    066     */
    067    private final Trie<K, V> delegate;
    068
    069    /**
    070     * Constructor that wraps (not copies).
    071     *
    072     * @param trie  The trie to decorate, must not be null
    073     * @throws NullPointerException if trie is null
    074     */
    075    public UnmodifiableTrie(final Trie<K, ? extends V> trie) {
    076        @SuppressWarnings("unchecked") // safe to upcast
    077        final Trie<K, V> tmpTrie = (Trie<K, V>) Objects.requireNonNull(trie, "trie");
    078        this.delegate = tmpTrie;
    079    }
    080
    081    /**
    082     * Always throws {@link UnsupportedOperationException}.
    083     *
    084     * @throws UnsupportedOperationException Always thrown.
    085     */
    086    @Override
    087    public void clear() {
    088        throw new UnsupportedOperationException();
    089    }
    090
    091    @Override
    092    public Comparator<? super K> comparator() {
    093        return delegate.comparator();
    094    }
    095
    096    @Override
    097    public boolean containsKey(final Object key) {
    098        return delegate.containsKey(key);
    099    }
    100
    101    @Override
    102    public boolean containsValue(final Object value) {
    103        return delegate.containsValue(value);
    104    }
    105
    106    @Override
    107    public Set<Entry<K, V>> entrySet() {
    108        return UnmodifiableEntrySet.unmodifiableEntrySet(delegate.entrySet());
    109    }
    110
    111    @Override
    112    public boolean equals(final Object obj) {
    113        return delegate.equals(obj);
    114    }
    115
    116    @Override
    117    public K firstKey() {
    118        return delegate.firstKey();
    119    }
    120
    121    @Override
    122    public V get(final Object key) {
    123        return delegate.get(key);
    124    }
    125
    126    @Override
    127    public int hashCode() {
    128        return delegate.hashCode();
    129    }
    130
    131    @Override
    132    public SortedMap<K, V> headMap(final K toKey) {
    133        return Collections.unmodifiableSortedMap(delegate.headMap(toKey));
    134    }
    135
    136    @Override
    137    public boolean isEmpty() {
    138        return delegate.isEmpty();
    139    }
    140
    141    @Override
    142    public Set<K> keySet() {
    143        return Collections.unmodifiableSet(delegate.keySet());
    144    }
    145
    146    @Override
    147    public K lastKey() {
    148        return delegate.lastKey();
    149    }
    150
    151    @Override
    152    public OrderedMapIterator<K, V> mapIterator() {
    153        final OrderedMapIterator<K, V> it = delegate.mapIterator();
    154        return UnmodifiableOrderedMapIterator.unmodifiableOrderedMapIterator(it);
    155    }
    156
    157    @Override
    158    public K nextKey(final K key) {
    159        return delegate.nextKey(key);
    160    }
    161
    162    @Override
    163    public SortedMap<K, V> prefixMap(final K key) {
    164        return Collections.unmodifiableSortedMap(delegate.prefixMap(key));
    165    }
    166
    167    @Override
    168    public K previousKey(final K key) {
    169        return delegate.previousKey(key);
    170    }
    171
    172    /**
    173     * Always throws {@link UnsupportedOperationException}.
    174     *
    175     * @param key Ignored.
    176     * @param value Ignored.
    177     * @throws UnsupportedOperationException Always thrown.
    178     */
    179    @Override
    180    public V put(final K key, final V value) {
    181        throw new UnsupportedOperationException();
    182    }
    183
    184    /**
    185     * Always throws {@link UnsupportedOperationException}.
    186     *
    187     * @param m Ignored.
    188     * @throws UnsupportedOperationException Always thrown.
    189     */
    190    @Override
    191    public void putAll(final Map<? extends K, ? extends V> m) {
    192        throw new UnsupportedOperationException();
    193    }
    194
    195    /**
    196     * Always throws {@link UnsupportedOperationException}.
    197     *
    198     * @param key Ignored.
    199     * @throws UnsupportedOperationException Always thrown.
    200     */
    201    @Override
    202    public V remove(final Object key) {
    203        throw new UnsupportedOperationException();
    204    }
    205
    206    @Override
    207    public int size() {
    208        return delegate.size();
    209    }
    210
    211    @Override
    212    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
    213        return Collections.unmodifiableSortedMap(delegate.subMap(fromKey, toKey));
    214    }
    215
    216    @Override
    217    public SortedMap<K, V> tailMap(final K fromKey) {
    218        return Collections.unmodifiableSortedMap(delegate.tailMap(fromKey));
    219    }
    220
    221    @Override
    222    public String toString() {
    223        return delegate.toString();
    224    }
    225
    226    @Override
    227    public Collection<V> values() {
    228        return Collections.unmodifiableCollection(delegate.values());
    229    }
    230
    231}