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1   /*
2    * ModeShape (http://www.modeshape.org)
3    * See the COPYRIGHT.txt file distributed with this work for information
4    * regarding copyright ownership.  Some portions may be licensed
5    * to Red Hat, Inc. under one or more contributor license agreements.
6    * See the AUTHORS.txt file in the distribution for a full listing of 
7    * individual contributors.
8    *
9    * Unless otherwise indicated, all code in ModeShape is licensed
10   * to you under the terms of the GNU Lesser General Public License as
11   * published by the Free Software Foundation; either version 2.1 of
12   * the License, or (at your option) any later version.
13   * 
14   * ModeShape is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17   * Lesser General Public License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this software; if not, write to the Free
21   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23   */
24  package org.modeshape.common.collection;
25  
26  import java.util.Iterator;
27  
28  /**
29   * An {@link Iterator} implementation that only allows reading elements, used as a wrapper around another iterator to make the
30   * contents immutable to the user of this iterator.
31   * 
32   * @param <T> the type of the elements over which the iteration is being performed
33   */
34  public final class ReadOnlyIterator<T> implements Iterator<T> {
35  
36      private final Iterator<T> delegate;
37  
38      public ReadOnlyIterator( Iterator<T> delegate ) {
39          this.delegate = delegate;
40          assert this.delegate != null;
41      }
42  
43      /**
44       * {@inheritDoc}
45       * 
46       * @see java.util.Iterator#hasNext()
47       */
48      public boolean hasNext() {
49          return delegate.hasNext();
50      }
51  
52      /**
53       * {@inheritDoc}
54       * 
55       * @see java.util.Iterator#next()
56       */
57      public T next() {
58          return delegate.next();
59      }
60  
61      /**
62       * {@inheritDoc}
63       * 
64       * @see java.util.Iterator#remove()
65       */
66      public void remove() {
67          throw new UnsupportedOperationException();
68      }
69  
70  }