1 /* 2 * $Header$ 3 * $Revision$ 4 * $Date$ 5 * 6 * ==================================================================== 7 * 8 * Copyright 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 are 13 * met: 14 * 15 * * Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 18 * * Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * * Neither the name of the Jaxen Project nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * ==================================================================== 39 * This software consists of voluntary contributions made by many 40 * individuals on behalf of the Jaxen Project and was originally 41 * created by bob mcwhirter <bob@werken.com> and 42 * James Strachan <jstrachan@apache.org>. For more information on the 43 * Jaxen Project, please see <http://www.jaxen.org/>. 44 * 45 * $Id$ 46 */ 47 48 49 50 package org.jaxen.util; 51 52 import java.util.Iterator; 53 import java.util.LinkedList; 54 import java.util.NoSuchElementException; 55 56 import org.jaxen.JaxenConstants; 57 import org.jaxen.Navigator; 58 import org.jaxen.UnsupportedAxisException; 59 60 /** 61 * 62 * Represents the XPath <code>preceding-sibling</code> axis. 63 * The "<code>preceding-sibling</code> axis contains all the 64 * preceding siblings of the context node; if the context node is an 65 * attribute node or namespace node, the <code>preceding-sibling</code> 66 * axis is empty." 67 * 68 * @version 1.2b12 69 * 70 */ 71 public class PrecedingSiblingAxisIterator implements Iterator 72 { 73 private Object contextNode; 74 private Navigator navigator; 75 76 private Iterator siblingIter; 77 private Object nextObj; 78 79 /** 80 * Create a new <code>preceding-sibling</code> axis iterator. 81 * 82 * @param contextNode the node to start from 83 * @param navigator the object model specific navigator 84 */ 85 public PrecedingSiblingAxisIterator(Object contextNode, 86 Navigator navigator) throws UnsupportedAxisException 87 { 88 this.contextNode = contextNode; 89 this.navigator = navigator; 90 91 init(); 92 if ( siblingIter.hasNext() ) 93 { 94 this.nextObj = siblingIter.next(); 95 } 96 } 97 98 private void init() throws UnsupportedAxisException 99 { 100 101 Object parent = this.navigator.getParentNode( this.contextNode ); 102 103 if ( parent != null ) 104 { 105 Iterator childIter = this.navigator.getChildAxisIterator( parent ); 106 LinkedList siblings = new LinkedList(); 107 108 while ( childIter.hasNext() ) 109 { 110 Object eachChild = childIter.next(); 111 if ( eachChild.equals(this.contextNode) ) 112 { 113 break; 114 } 115 siblings.addFirst( eachChild ); 116 } 117 118 this.siblingIter = siblings.iterator(); 119 120 } 121 else { 122 this.siblingIter = JaxenConstants.EMPTY_ITERATOR; 123 } 124 125 } 126 127 /** 128 * Returns true if there are any preceding siblings remaining; false otherwise. 129 * 130 * @return true if any preceding siblings remain; false otherwise 131 * 132 * @see java.util.Iterator#hasNext() 133 */ 134 public boolean hasNext() 135 { 136 return ( this.nextObj != null ); 137 } 138 139 /** 140 * Returns the next preceding sibling. 141 * 142 * @return the next preceding sibling 143 * 144 * @throws NoSuchElementException if no preceding siblings remain 145 * 146 * @see java.util.Iterator#next() 147 */ 148 public Object next() throws NoSuchElementException 149 { 150 if ( ! hasNext() ) 151 { 152 throw new NoSuchElementException(); 153 } 154 155 Object obj = this.nextObj; 156 if ( siblingIter.hasNext() ) 157 { 158 this.nextObj = siblingIter.next(); 159 } 160 else { 161 this.nextObj = null; 162 } 163 return obj; 164 } 165 166 /** 167 * This operation is not supported. 168 * 169 * @throws UnsupportedOperationException 170 */ 171 public void remove() throws UnsupportedOperationException 172 { 173 throw new UnsupportedOperationException(); 174 } 175 176 }