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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/PrecedingSiblingAxisIterator.java,v 1.12 2005/04/11 19:14:10 elharo Exp $
3    * $Revision: 1.12 $
4    * $Date: 2005/04/11 19:14:10 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions
13   * are met:
14   * 
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows 
20   *    these conditions in the documentation and/or other materials 
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   * 
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   * 
31   * In addition, we request (but do not require) that you include in the 
32   * end-user documentation provided with the redistribution and/or in the 
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos 
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many 
54   * individuals on behalf of the Jaxen Project and was originally 
55   * created by bob mcwhirter <bob@werken.com> and 
56   * James Strachan <jstrachan@apache.org>.  For more information on the 
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   * 
59   * $Id: PrecedingSiblingAxisIterator.java,v 1.12 2005/04/11 19:14:10 elharo Exp $
60   */
61  
62  
63  
64  package org.jaxen.util;
65  
66  import java.util.Iterator;
67  import java.util.LinkedList;
68  import java.util.NoSuchElementException;
69  
70  import org.jaxen.JaxenConstants;
71  import org.jaxen.Navigator;
72  import org.jaxen.UnsupportedAxisException;
73  
74  public class PrecedingSiblingAxisIterator implements Iterator
75  {
76      private Object    contextNode;
77      private Navigator navigator;
78  
79      private Iterator  siblingIter;
80      private Object    nextObj;
81  
82      public PrecedingSiblingAxisIterator(Object contextNode,
83                                          Navigator navigator) throws UnsupportedAxisException
84      {
85          this.contextNode = contextNode;
86          this.navigator   = navigator;
87  
88          init();
89          if ( siblingIter.hasNext() )
90          {
91              this.nextObj = siblingIter.next();
92          }
93      }
94  
95      private void init() throws UnsupportedAxisException
96      {
97          
98          Object parent = this.navigator.getParentNode( this.contextNode );
99  
100         if ( parent != null )
101         {
102             Iterator childIter = this.navigator.getChildAxisIterator( parent );
103             LinkedList siblings = new LinkedList();
104             
105             while ( childIter.hasNext() )
106             {
107                 Object eachChild = childIter.next();
108                 if ( eachChild.equals(this.contextNode) )
109                 {
110                     break;
111                 }
112                 siblings.addFirst( eachChild );
113             }
114             
115             this.siblingIter = siblings.iterator();
116             
117         }
118         else {
119             this.siblingIter = JaxenConstants.EMPTY_ITERATOR;
120         }
121         
122     }
123 
124     public boolean hasNext()
125     {
126         return ( this.nextObj != null );
127     }
128 
129     public Object next() throws NoSuchElementException
130     {
131         if ( ! hasNext() )
132         {
133             throw new NoSuchElementException();
134         }
135 
136         Object obj = this.nextObj;
137         if ( siblingIter.hasNext() )
138         {
139             this.nextObj = siblingIter.next();
140         }
141         else {
142             this.nextObj = null;
143         }
144         return obj;
145     }
146 
147     public void remove() throws UnsupportedOperationException
148     {
149         throw new UnsupportedOperationException();
150     }
151 
152 }