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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/PrecedingSiblingAxisIterator.java,v 1.13 2005/06/28 13:44:44 elharo Exp $
    3    * $Revision: 1.13 $
    4    * $Date: 2005/06/28 13:44:44 $
    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 1.13 2005/06/28 13:44:44 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 }