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 2.0.0
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 * @throws UnsupportedAxisException if the navigator does not support the preceding-sibling axis
85 */
86 public PrecedingSiblingAxisIterator(Object contextNode,
87 Navigator navigator) throws UnsupportedAxisException
88 {
89 this.contextNode = contextNode;
90 this.navigator = navigator;
91
92 init();
93 if ( siblingIter.hasNext() )
94 {
95 this.nextObj = siblingIter.next();
96 }
97 }
98
99 private void init() throws UnsupportedAxisException
100 {
101
102 Object parent = this.navigator.getParentNode( this.contextNode );
103
104 if ( parent != null )
105 {
106 Iterator childIter = this.navigator.getChildAxisIterator( parent );
107 LinkedList siblings = new LinkedList();
108
109 while ( childIter.hasNext() )
110 {
111 Object eachChild = childIter.next();
112 if ( eachChild.equals(this.contextNode) )
113 {
114 break;
115 }
116 siblings.addFirst( eachChild );
117 }
118
119 this.siblingIter = siblings.iterator();
120
121 }
122 else {
123 this.siblingIter = JaxenConstants.EMPTY_ITERATOR;
124 }
125
126 }
127
128 /**
129 * Returns true if there are any preceding siblings remaining; false otherwise.
130 *
131 * @return true if any preceding siblings remain; false otherwise
132 *
133 * @see java.util.Iterator#hasNext()
134 */
135 public boolean hasNext()
136 {
137 return ( this.nextObj != null );
138 }
139
140 /**
141 * Returns the next preceding sibling.
142 *
143 * @return the next preceding sibling
144 *
145 * @throws NoSuchElementException if no preceding siblings remain
146 *
147 * @see java.util.Iterator#next()
148 */
149 public Object next() throws NoSuchElementException
150 {
151 if ( ! hasNext() )
152 {
153 throw new NoSuchElementException();
154 }
155
156 Object obj = this.nextObj;
157 if ( siblingIter.hasNext() )
158 {
159 this.nextObj = siblingIter.next();
160 }
161 else {
162 this.nextObj = null;
163 }
164 return obj;
165 }
166
167 /**
168 * This operation is not supported.
169 *
170 * @throws UnsupportedOperationException always
171 */
172 public void remove() throws UnsupportedOperationException
173 {
174 throw new UnsupportedOperationException();
175 }
176
177 }