001/*
002 * ModeShape (http://www.modeshape.org)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *       http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.modeshape.common.collection;
017
018import java.util.Iterator;
019
020/**
021 * An {@link Iterator} implementation that only allows reading elements, used as a wrapper around another iterator to make the
022 * contents immutable to the user of this iterator.
023 * 
024 * @param <T> the type of the elements over which the iteration is being performed
025 */
026public final class ReadOnlyIterator<T> implements Iterator<T> {
027
028    public static <T> ReadOnlyIterator<T> around( Iterator<T> delegate ) {
029        return new ReadOnlyIterator<T>(delegate);
030    }
031
032    private final Iterator<T> delegate;
033
034    public ReadOnlyIterator( Iterator<T> delegate ) {
035        this.delegate = delegate;
036        assert this.delegate != null;
037    }
038
039    @Override
040    public boolean hasNext() {
041        return delegate.hasNext();
042    }
043
044    @Override
045    public T next() {
046        return delegate.next();
047    }
048
049    @Override
050    public void remove() {
051        throw new UnsupportedOperationException();
052    }
053
054}