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.io.IOException;
020import java.io.ObjectInputStream;
021import java.io.ObjectOutputStream;
022import java.io.Serializable;
023import java.util.Collection;
024import java.util.Comparator;
025import java.util.Map;
026import java.util.Set;
027import java.util.SortedMap;
028
029import org.apache.commons.collections4.Unmodifiable;
030import org.apache.commons.collections4.collection.UnmodifiableCollection;
031import org.apache.commons.collections4.set.UnmodifiableSet;
032
033/**
034 * Decorates another {@code SortedMap} to ensure it can't be altered.
035 * <p>
036 * This class is Serializable from Commons Collections 3.1.
037 * </p>
038 * <p>
039 * Attempts to modify it will result in an UnsupportedOperationException.
040 * </p>
041 *
042 * @param <K> the type of the keys in this map
043 * @param <V> the type of the values in this map
044 * @since 3.0
045 */
046public final class UnmodifiableSortedMap<K, V>
047        extends AbstractSortedMapDecorator<K, V>
048        implements Unmodifiable, Serializable {
049
050    /** Serialization version */
051    private static final long serialVersionUID = 5805344239827376360L;
052
053    /**
054     * Factory method to create an unmodifiable sorted map.
055     *
056     * @param <K>  the key type
057     * @param <V>  the value type
058     * @param map  the map to decorate, must not be null
059     * @return a new unmodifiable sorted map
060     * @throws NullPointerException if map is null
061     * @since 4.0
062     */
063    public static <K, V> SortedMap<K, V> unmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
064        if (map instanceof Unmodifiable) {
065            @SuppressWarnings("unchecked") // safe to upcast
066            final SortedMap<K, V> tmpMap = (SortedMap<K, V>) map;
067            return tmpMap;
068        }
069        return new UnmodifiableSortedMap<>(map);
070    }
071
072    /**
073     * Constructor that wraps (not copies).
074     *
075     * @param map  the map to decorate, must not be null
076     * @throws NullPointerException if map is null
077     */
078    @SuppressWarnings("unchecked") // safe to upcast
079    private UnmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
080        super((SortedMap<K, V>) map);
081    }
082
083    @Override
084    public void clear() {
085        throw new UnsupportedOperationException();
086    }
087
088    @Override
089    public Comparator<? super K> comparator() {
090        return decorated().comparator();
091    }
092
093    @Override
094    public Set<Map.Entry<K, V>> entrySet() {
095        return UnmodifiableEntrySet.unmodifiableEntrySet(super.entrySet());
096    }
097
098    @Override
099    public K firstKey() {
100        return decorated().firstKey();
101    }
102
103    @Override
104    public SortedMap<K, V> headMap(final K toKey) {
105        return new UnmodifiableSortedMap<>(decorated().headMap(toKey));
106    }
107
108    @Override
109    public Set<K> keySet() {
110        return UnmodifiableSet.unmodifiableSet(super.keySet());
111    }
112
113    @Override
114    public K lastKey() {
115        return decorated().lastKey();
116    }
117
118    @Override
119    public V put(final K key, final V value) {
120        throw new UnsupportedOperationException();
121    }
122
123    @Override
124    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
125        throw new UnsupportedOperationException();
126    }
127
128    /**
129     * Deserializes the map in using a custom routine.
130     *
131     * @param in  the input stream
132     * @throws IOException if an error occurs while reading from the stream
133     * @throws ClassNotFoundException if an object read from the stream cannot be loaded
134     * @since 3.1
135     */
136    @SuppressWarnings("unchecked")
137    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
138        in.defaultReadObject();
139        map = (Map<K, V>) in.readObject();
140    }
141
142    @Override
143    public V remove(final Object key) {
144        throw new UnsupportedOperationException();
145    }
146
147    @Override
148    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
149        return new UnmodifiableSortedMap<>(decorated().subMap(fromKey, toKey));
150    }
151
152    @Override
153    public SortedMap<K, V> tailMap(final K fromKey) {
154        return new UnmodifiableSortedMap<>(decorated().tailMap(fromKey));
155    }
156
157    @Override
158    public Collection<V> values() {
159        return UnmodifiableCollection.unmodifiableCollection(super.values());
160    }
161
162    /**
163     * Serializes this object to an ObjectOutputStream.
164     *
165     * @param out the target ObjectOutputStream.
166     * @throws IOException thrown when an I/O errors occur writing to the target stream.
167     * @since 3.1
168     */
169    private void writeObject(final ObjectOutputStream out) throws IOException {
170        out.defaultWriteObject();
171        out.writeObject(map);
172    }
173
174}