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.Map;
025import java.util.Set;
026import java.util.SortedMap;
027
028import org.apache.commons.collections4.BoundedMap;
029import org.apache.commons.collections4.CollectionUtils;
030import org.apache.commons.collections4.collection.UnmodifiableCollection;
031import org.apache.commons.collections4.set.UnmodifiableSet;
032
033/**
034 * Decorates another <code>SortedMap</code> to fix the size blocking add/remove.
035 * <p>
036 * Any action that would change the size of the map is disallowed.
037 * The put method is allowed to change the value associated with an existing
038 * key however.
039 * </p>
040 * <p>
041 * If trying to remove or clear the map, an UnsupportedOperationException is
042 * thrown. If trying to put a new mapping into the map, an
043 * IllegalArgumentException is thrown. This is because the put method can
044 * succeed if the mapping's key already exists in the map, so the put method
045 * is not always unsupported.
046 * </p>
047 * <p>
048 * <strong>Note that FixedSizeSortedMap is not synchronized and is not thread-safe.</strong>
049 * If you wish to use this map from multiple threads concurrently, you must use
050 * appropriate synchronization. The simplest approach is to wrap this map
051 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw
052 * exceptions when accessed by concurrent threads without synchronization.
053 * </p>
054 * <p>
055 * This class is Serializable from Commons Collections 3.1.
056 * </p>
057 *
058 * @param <K> the type of the keys in this map
059 * @param <V> the type of the values in this map
060 * @since 3.0
061 */
062public class FixedSizeSortedMap<K, V>
063        extends AbstractSortedMapDecorator<K, V>
064        implements BoundedMap<K, V>, Serializable {
065
066    /** Serialization version */
067    private static final long serialVersionUID = 3126019624511683653L;
068
069    /**
070     * Factory method to create a fixed size sorted map.
071     *
072     * @param <K>  the key type
073     * @param <V>  the value type
074     * @param map  the map to decorate, must not be null
075     * @return a new fixed size sorted map
076     * @throws NullPointerException if map is null
077     * @since 4.0
078     */
079    public static <K, V> FixedSizeSortedMap<K, V> fixedSizeSortedMap(final SortedMap<K, V> map) {
080        return new FixedSizeSortedMap<>(map);
081    }
082
083    //-----------------------------------------------------------------------
084    /**
085     * Constructor that wraps (not copies).
086     *
087     * @param map  the map to decorate, must not be null
088     * @throws NullPointerException if map is null
089     */
090    protected FixedSizeSortedMap(final SortedMap<K, V> map) {
091        super(map);
092    }
093
094    /**
095     * Gets the map being decorated.
096     *
097     * @return the decorated map
098     */
099    protected SortedMap<K, V> getSortedMap() {
100        return (SortedMap<K, V>) map;
101    }
102
103    //-----------------------------------------------------------------------
104    /**
105     * Write the map out using a custom routine.
106     *
107     * @param out  the output stream
108     * @throws IOException if an error occurs while writing to the stream
109     */
110    private void writeObject(final ObjectOutputStream out) throws IOException {
111        out.defaultWriteObject();
112        out.writeObject(map);
113    }
114
115    /**
116     * Read the map in using a custom routine.
117     *
118     * @param in the input stream
119     * @throws IOException if an error occurs while reading from the stream
120     * @throws ClassNotFoundException if an object read from the stream can not be loaded
121     */
122    @SuppressWarnings("unchecked") // (1) should only fail if input stream is incorrect
123    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
124        in.defaultReadObject();
125        map = (Map<K, V>) in.readObject(); // (1)
126    }
127
128    //-----------------------------------------------------------------------
129    @Override
130    public V put(final K key, final V value) {
131        if (map.containsKey(key) == false) {
132            throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size");
133        }
134        return map.put(key, value);
135    }
136
137    @Override
138    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
139        if (CollectionUtils.isSubCollection(mapToCopy.keySet(), keySet())) {
140            throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size");
141        }
142        map.putAll(mapToCopy);
143    }
144
145    @Override
146    public void clear() {
147        throw new UnsupportedOperationException("Map is fixed size");
148    }
149
150    @Override
151    public V remove(final Object key) {
152        throw new UnsupportedOperationException("Map is fixed size");
153    }
154
155    @Override
156    public Set<Map.Entry<K, V>> entrySet() {
157        return UnmodifiableSet.unmodifiableSet(map.entrySet());
158    }
159
160    @Override
161    public Set<K> keySet() {
162        return UnmodifiableSet.unmodifiableSet(map.keySet());
163    }
164
165    @Override
166    public Collection<V> values() {
167        return UnmodifiableCollection.unmodifiableCollection(map.values());
168    }
169
170    //-----------------------------------------------------------------------
171    @Override
172    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
173        return new FixedSizeSortedMap<>(getSortedMap().subMap(fromKey, toKey));
174    }
175
176    @Override
177    public SortedMap<K, V> headMap(final K toKey) {
178        return new FixedSizeSortedMap<>(getSortedMap().headMap(toKey));
179    }
180
181    @Override
182    public SortedMap<K, V> tailMap(final K fromKey) {
183        return new FixedSizeSortedMap<>(getSortedMap().tailMap(fromKey));
184    }
185
186    @Override
187    public boolean isFull() {
188        return true;
189    }
190
191    @Override
192    public int maxSize() {
193        return size();
194    }
195
196}