ReverseListIterator


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8     * under the terms of the GNU Lesser General Public License as
9     * published by the Free Software Foundation; either version 2.1 of
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14    * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15    * Lesser General Public License for more details.
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21    */
22  package org.jboss.util.collection;
23  
24  import java.util.Iterator  ;
25  import java.util.List  ;
26  import java.util.NoSuchElementException  ;
27  
28  /**
29   * An iterator that returns elements in reverse order from a list.
30   *
31   * @version <tt>$Revision: 1958 $</tt>
32   * @author  <a HREF="mailto:jason@planet57.com">Jason Dillon</a>
33   */
34  public class ReverseListIterator
35     implements Iterator  
36  {
37     /** The list to get elements from */
38     protected final List   list;
39     
40     /** The current index of the list */
41     protected int current;
42  
43     /**
44      * Construct a ReverseListIterator for the given list.
45      *
46      * @param list    List to iterate over.
47      */
48     public ReverseListIterator(final List   list) {
49        this.list = list;
50        current = list.size() - 1;
51     }
52  
53     /**
54      * Check if there are more elements.
55      *
56      * @return  True if there are more elements.
57      */
58     public boolean hasNext() {
59        return current > 0;
60     }
61  
62     /**
63      * Get the next element.
64      *
65      * @return  The next element.
66      *
67      * @throws NoSuchElementException
68      */
69     public Object   next() {
70        if (current <= 0) {
71           throw new NoSuchElementException  ();
72        }
73        
74        return list.get(current--);
75     }
76  
77     /**
78      * Remove the current element.
79      */
80     public void remove() {
81        list.remove(current);
82     }
83  }
84
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