Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
PrecedingAxisIterator |
|
| 4.6;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 | } |