Coverage Report - org.jaxen.util.PrecedingAxisIterator
 
Classes in this File Line Coverage Branch Coverage Complexity
PrecedingAxisIterator
90%
38/42
100%
8/8
4.6
 
 1  
 package org.jaxen.util;
 2  
 
 3  
 /*
 4  
  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/PrecedingAxisIterator.java,v 1.11 2006/11/13 22:10:09 elharo Exp $
 5  
  * $Revision: 1.11 $
 6  
  * $Date: 2006/11/13 22:10:09 $
 7  
  *
 8  
  * ====================================================================
 9  
  *
 10  
  * Copyright 2000-2005 bob mcwhirter & James Strachan.
 11  
  * All rights reserved.
 12  
  *
 13  
  *
 14  
  * Redistribution and use in source and binary forms, with or without
 15  
  * modification, are permitted provided that the following conditions are
 16  
  * met:
 17  
  * 
 18  
  *   * Redistributions of source code must retain the above copyright
 19  
  *     notice, this list of conditions and the following disclaimer.
 20  
  * 
 21  
  *   * Redistributions in binary form must reproduce the above copyright
 22  
  *     notice, this list of conditions and the following disclaimer in the
 23  
  *     documentation and/or other materials provided with the distribution.
 24  
  * 
 25  
  *   * Neither the name of the Jaxen Project nor the names of its
 26  
  *     contributors may be used to endorse or promote products derived 
 27  
  *     from this software without specific prior written permission.
 28  
  * 
 29  
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 30  
  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 31  
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 32  
  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 33  
  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 34  
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 35  
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 36  
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 37  
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 38  
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 39  
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 40  
  *
 41  
  * ====================================================================
 42  
  * This software consists of voluntary contributions made by many
 43  
  * individuals on behalf of the Jaxen Project and was originally
 44  
  * created by bob mcwhirter <bob@werken.com> and
 45  
  * James Strachan <jstrachan@apache.org>.  For more information on the
 46  
  * Jaxen Project, please see <http://www.jaxen.org/>.
 47  
  *
 48  
  * $Id: PrecedingAxisIterator.java,v 1.11 2006/11/13 22:10:09 elharo Exp $
 49  
 */
 50  
 
 51  
 import org.jaxen.JaxenConstants;
 52  
 import org.jaxen.JaxenRuntimeException;
 53  
 import org.jaxen.Navigator;
 54  
 import org.jaxen.UnsupportedAxisException;
 55  
 
 56  
 import java.util.ArrayList;
 57  
 import java.util.Iterator;
 58  
 import java.util.ListIterator;
 59  
 import java.util.NoSuchElementException;
 60  
 
 61  
 /**
 62  
  * <p>
 63  
  * Represents the XPath <code>preceding</code> axis. 
 64  
  * The "<code>preceding</code> axis contains all nodes in the same document as the context 
 65  
  * node that are before the context node in document order, excluding any ancestors 
 66  
  * and excluding attribute nodes and namespace nodes."
 67  
  * 
 68  
  * <p>
 69  
  * This implementation of '<code>preceding</code>' works like so:
 70  
  * the <code>preceding</code> axis includes preceding siblings of this node and 
 71  
  * their descendants. Also, for each ancestor node of this node, it includes
 72  
  * all preceding siblings of that ancestor, and their descendants. Finally, it
 73  
  * includes the ancestor nodes themselves.
 74  
  * </p>
 75  
  * 
 76  
  * <p>
 77  
  * The reversed <code>descendant-or-self</code> axes that are required are calculated using a
 78  
  * stack of reversed 'child-or-self' axes. When asked for a node, it is always taken
 79  
  * from a child-or-self axis. If it was the last node on that axis, the node is returned.
 80  
  * Otherwise, this axis is pushed on the stack, and the process is repeated with the child-or-self
 81  
  * of the node. Eventually this recurses down to the last descendant of any node, then works
 82  
  * back up to the root.
 83  
  * </p>
 84  
  * 
 85  
  * <p>
 86  
  * Most object models could provide a faster implementation of the reversed
 87  
  * 'children-or-self' used here.</p>
 88  
  * 
 89  
  * @version 1.2b12
 90  
  */
 91  
 public class PrecedingAxisIterator implements Iterator
 92  
 {
 93  
     private Iterator ancestorOrSelf;
 94  
     private Iterator precedingSibling;
 95  
     private ListIterator childrenOrSelf;
 96  
     private ArrayList stack;
 97  
 
 98  
     private Navigator navigator;
 99  
 
 100  
     /**
 101  
      * Create a new <code>preceding</code> axis iterator.
 102  
      * 
 103  
      * @param contextNode the node to start from
 104  
      * @param navigator the object model specific navigator
 105  
      */
 106  
     public PrecedingAxisIterator(Object contextNode,
 107  
                                  Navigator navigator) throws UnsupportedAxisException
 108  158
     {
 109  158
         this.navigator = navigator;
 110  158
         this.ancestorOrSelf = navigator.getAncestorOrSelfAxisIterator(contextNode);
 111  158
         this.precedingSibling = JaxenConstants.EMPTY_ITERATOR;
 112  158
         this.childrenOrSelf = JaxenConstants.EMPTY_LIST_ITERATOR;
 113  158
         this.stack = new ArrayList();
 114  158
     }
 115  
 
 116  
 
 117  
     /**
 118  
      * Returns true if there are any preceding nodes remaining; false otherwise.
 119  
      * 
 120  
      * @return true if any preceding nodes remain; false otherwise
 121  
      * 
 122  
      * @see java.util.Iterator#hasNext()
 123  
      */
 124  
     public boolean hasNext()
 125  
     {
 126  
         try
 127  
         {
 128  1784
             while (!childrenOrSelf.hasPrevious())
 129  
             {
 130  674
                 if (stack.isEmpty())
 131  
                 {
 132  806
                     while (!precedingSibling.hasNext())
 133  
                     {
 134  622
                         if (!ancestorOrSelf.hasNext())
 135  
                         {
 136  156
                             return false;
 137  
                         }
 138  466
                         Object contextNode = ancestorOrSelf.next();
 139  466
                         precedingSibling = new PrecedingSiblingAxisIterator(contextNode, navigator);
 140  466
                     }
 141  184
                     Object node = precedingSibling.next();
 142  184
                     childrenOrSelf = childrenOrSelf(node);
 143  184
                 }
 144  
                 else
 145  
                 {
 146  334
                     childrenOrSelf = (ListIterator) stack.remove(stack.size()-1);
 147  
                 }
 148  334
             }
 149  1110
             return true;
 150  
         }
 151  0
         catch (UnsupportedAxisException e)
 152  
         {
 153  0
             throw new JaxenRuntimeException(e);
 154  
         }
 155  
     }
 156  
 
 157  
     private ListIterator childrenOrSelf(Object node)
 158  
     {
 159  
         try
 160  
         {
 161  518
             ArrayList reversed = new ArrayList();
 162  518
             reversed.add(node);
 163  518
             Iterator childAxisIterator = navigator.getChildAxisIterator(node);
 164  518
             if (childAxisIterator != null)
 165  
             {
 166  852
                 while (childAxisIterator.hasNext())
 167  
                 {
 168  334
                     reversed.add(childAxisIterator.next());
 169  334
                 }
 170  
             }
 171  518
             return reversed.listIterator(reversed.size());
 172  
         }
 173  0
         catch (UnsupportedAxisException e)
 174  
         {
 175  0
             throw new JaxenRuntimeException(e);
 176  
         }
 177  
     }
 178  
 
 179  
     /**
 180  
      * Returns the next preceding node.
 181  
      * 
 182  
      * @return the next preceding node
 183  
      * 
 184  
      * @throws NoSuchElementException if no preceding nodes remain
 185  
      * 
 186  
      * @see java.util.Iterator#next()
 187  
      */
 188  
     public Object next() throws NoSuchElementException
 189  
     {
 190  520
         if (!hasNext())
 191  
         {
 192  2
             throw new NoSuchElementException();
 193  
         }
 194  
         while (true)
 195  
         {
 196  852
             Object result = childrenOrSelf.previous();
 197  852
             if (childrenOrSelf.hasPrevious())
 198  
             {
 199  
                 // if this isn't 'self' construct 'descendant-or-self'
 200  334
                 stack.add(childrenOrSelf);
 201  334
                 childrenOrSelf = childrenOrSelf(result);
 202  334
                 continue;
 203  
             }
 204  518
             return result;
 205  
         }
 206  
     }
 207  
 
 208  
 
 209  
     /**
 210  
      * This operation is not supported.
 211  
      * 
 212  
      * @throws UnsupportedOperationException always
 213  
      */
 214  
     public void remove() throws UnsupportedOperationException
 215  
     {
 216  2
         throw new UnsupportedOperationException();
 217  
     }
 218  
     
 219  
 }