1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/PrecedingSiblingAxisIterator.java,v 1.16 2006/11/13 22:10:09 elharo Exp $
3 * $Revision: 1.16 $
4 * $Date: 2006/11/13 22:10:09 $
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: PrecedingSiblingAxisIterator.java,v 1.16 2006/11/13 22:10:09 elharo Exp $
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 }