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.iterators;
018    
019    import org.apache.commons.collections.MapIterator;
020    import org.apache.commons.collections.Unmodifiable;
021    
022    /** 
023     * Decorates a map iterator such that it cannot be modified.
024     *
025     * @since Commons Collections 3.0
026     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
027     * 
028     * @author Stephen Colebourne
029     */
030    public final class UnmodifiableMapIterator implements MapIterator, Unmodifiable {
031    
032        /** The iterator being decorated */
033        private MapIterator iterator;
034    
035        //-----------------------------------------------------------------------
036        /**
037         * Decorates the specified iterator such that it cannot be modified.
038         *
039         * @param iterator  the iterator to decorate
040         * @throws IllegalArgumentException if the iterator is null
041         */
042        public static MapIterator decorate(MapIterator iterator) {
043            if (iterator == null) {
044                throw new IllegalArgumentException("MapIterator must not be null");
045            }
046            if (iterator instanceof Unmodifiable) {
047                return iterator;
048            }
049            return new UnmodifiableMapIterator(iterator);
050        }
051        
052        //-----------------------------------------------------------------------
053        /**
054         * Constructor.
055         *
056         * @param iterator  the iterator to decorate
057         */
058        private UnmodifiableMapIterator(MapIterator iterator) {
059            super();
060            this.iterator = iterator;
061        }
062    
063        //-----------------------------------------------------------------------
064        public boolean hasNext() {
065            return iterator.hasNext();
066        }
067    
068        public Object next() {
069            return iterator.next();
070        }
071    
072        public Object getKey() {
073            return iterator.getKey();
074        }
075    
076        public Object getValue() {
077            return iterator.getValue();
078        }
079    
080        public Object setValue(Object value) {
081            throw new UnsupportedOperationException("setValue() is not supported");
082        }
083    
084        public void remove() {
085            throw new UnsupportedOperationException("remove() is not supported");
086        }
087    
088    }