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     */
017    package org.apache.commons.collections.map;
018    
019    import java.io.IOException;
020    import java.io.ObjectInputStream;
021    import java.io.ObjectOutputStream;
022    import java.io.Serializable;
023    import java.util.Collection;
024    import java.util.Map;
025    import java.util.Set;
026    
027    import org.apache.commons.collections.IterableMap;
028    import org.apache.commons.collections.MapIterator;
029    import org.apache.commons.collections.Unmodifiable;
030    import org.apache.commons.collections.collection.UnmodifiableCollection;
031    import org.apache.commons.collections.iterators.EntrySetMapIterator;
032    import org.apache.commons.collections.iterators.UnmodifiableMapIterator;
033    import org.apache.commons.collections.set.UnmodifiableSet;
034    
035    /**
036     * Decorates another <code>Map</code> to ensure it can't be altered.
037     * <p>
038     * This class is Serializable from Commons Collections 3.1.
039     *
040     * @since Commons Collections 3.0
041     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
042     * 
043     * @author Stephen Colebourne
044     */
045    public final class UnmodifiableMap
046            extends AbstractMapDecorator
047            implements IterableMap, Unmodifiable, Serializable {
048    
049        /** Serialization version */
050        private static final long serialVersionUID = 2737023427269031941L;
051    
052        /**
053         * Factory method to create an unmodifiable map.
054         * 
055         * @param map  the map to decorate, must not be null
056         * @throws IllegalArgumentException if map is null
057         */
058        public static Map decorate(Map map) {
059            if (map instanceof Unmodifiable) {
060                return map;
061            }
062            return new UnmodifiableMap(map);
063        }
064    
065        //-----------------------------------------------------------------------
066        /**
067         * Constructor that wraps (not copies).
068         * 
069         * @param map  the map to decorate, must not be null
070         * @throws IllegalArgumentException if map is null
071         */
072        private UnmodifiableMap(Map map) {
073            super(map);
074        }
075    
076        //-----------------------------------------------------------------------
077        /**
078         * Write the map out using a custom routine.
079         * 
080         * @param out  the output stream
081         * @throws IOException
082         * @since Commons Collections 3.1
083         */
084        private void writeObject(ObjectOutputStream out) throws IOException {
085            out.defaultWriteObject();
086            out.writeObject(map);
087        }
088    
089        /**
090         * Read the map in using a custom routine.
091         * 
092         * @param in  the input stream
093         * @throws IOException
094         * @throws ClassNotFoundException
095         * @since Commons Collections 3.1
096         */
097        private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
098            in.defaultReadObject();
099            map = (Map) in.readObject();
100        }
101    
102        //-----------------------------------------------------------------------
103        public void clear() {
104            throw new UnsupportedOperationException();
105        }
106    
107        public Object put(Object key, Object value) {
108            throw new UnsupportedOperationException();
109        }
110    
111        public void putAll(Map mapToCopy) {
112            throw new UnsupportedOperationException();
113        }
114    
115        public Object remove(Object key) {
116            throw new UnsupportedOperationException();
117        }
118    
119        public MapIterator mapIterator() {
120            if (map instanceof IterableMap) {
121                MapIterator it = ((IterableMap) map).mapIterator();
122                return UnmodifiableMapIterator.decorate(it);
123            } else {
124                MapIterator it = new EntrySetMapIterator(map);
125                return UnmodifiableMapIterator.decorate(it);
126            }
127        }
128    
129        public Set entrySet() {
130            Set set = super.entrySet();
131            return UnmodifiableEntrySet.decorate(set);
132        }
133    
134        public Set keySet() {
135            Set set = super.keySet();
136            return UnmodifiableSet.decorate(set);
137        }
138    
139        public Collection values() {
140            Collection coll = super.values();
141            return UnmodifiableCollection.decorate(coll);
142        }
143    
144    }