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1   /*
2    *  Copyright 2003-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License");
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License.
15   */
16  package net.sf.collections15;
17  
18  import java.util.Iterator;
19  
20  /***
21   * Defines an iterator that operates over an ordered collection.
22   * <p/>
23   * This iterator allows both forward and reverse iteration through the
24   * collection.
25   *
26   * @author Stephen Colebourne
27   * @version $Revision: 1.2 $ $Date: 2004/10/17 01:02:42 $
28   * @since Commons Collections 3.0
29   */
30  public interface OrderedIterator <E> extends Iterator<E>
31  {
32  
33      /***
34       * Checks to see if there is a previous element that can be iterated to.
35       *
36       * @return <code>true</code> if the iterator has a previous element
37       */
38      boolean hasPrevious();
39  
40      /***
41       * Gets the previous element from the collection.
42       *
43       * @return the previous element in the iteration
44       *
45       * @throws java.util.NoSuchElementException
46       *          if the iteration is finished
47       */
48      E previous();
49  }