001    /*
002     * JBoss DNA (http://www.jboss.org/dna)
003     * See the COPYRIGHT.txt file distributed with this work for information
004     * regarding copyright ownership.  Some portions may be licensed
005     * to Red Hat, Inc. under one or more contributor license agreements.
006     * See the AUTHORS.txt file in the distribution for a full listing of 
007     * individual contributors.
008     *
009     * Unless otherwise indicated, all code in JBoss DNA is licensed
010     * to you under the terms of the GNU Lesser General Public License as
011     * published by the Free Software Foundation; either version 2.1 of
012     * the License, or (at your option) any later version.
013     * 
014     * JBoss DNA is distributed in the hope that it will be useful,
015     * but WITHOUT ANY WARRANTY; without even the implied warranty of
016     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017     * Lesser General Public License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this software; if not, write to the Free
021     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
022     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
023     */
024    package org.jboss.dna.common.collection;
025    
026    import java.util.Iterator;
027    
028    /**
029     * An {@link Iterator} implementation that only allows reading elements, used as a wrapper around another iterator to make the
030     * contents appear to be immutable.
031     * 
032     * @param <T> the type that is being iterated over
033     */
034    public final class ReadOnlyIterator<T> implements Iterator<T> {
035    
036        private final Iterator<T> delegate;
037    
038        public ReadOnlyIterator( Iterator<T> delegate ) {
039            this.delegate = delegate;
040            assert this.delegate != null;
041        }
042    
043        /**
044         * {@inheritDoc}
045         * 
046         * @see java.util.Iterator#hasNext()
047         */
048        public boolean hasNext() {
049            return delegate.hasNext();
050        }
051    
052        /**
053         * {@inheritDoc}
054         * 
055         * @see java.util.Iterator#next()
056         */
057        public T next() {
058            return delegate.next();
059        }
060    
061        /**
062         * {@inheritDoc}
063         * 
064         * @see java.util.Iterator#remove()
065         */
066        public void remove() {
067            throw new UnsupportedOperationException();
068        }
069    
070    }