Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
PrecedingAxisIterator |
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| 4.6;4.6 |
1 | package org.jaxen.util; |
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2 | ||
3 | /* |
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4 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/PrecedingAxisIterator.java,v 1.8 2005/07/24 11:51:14 elharo Exp $ |
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5 | * $Revision: 1.8 $ |
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6 | * $Date: 2005/07/24 11:51:14 $ |
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7 | * |
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8 | * ==================================================================== |
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9 | * |
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10 | * Copyright (C) 2000-2005 bob mcwhirter & James Strachan. |
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11 | * All rights reserved. |
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12 | * |
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13 | * Redistribution and use in source and binary forms, with or without |
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14 | * modification, are permitted provided that the following conditions |
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15 | * are met: |
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16 | * |
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17 | * 1. Redistributions of source code must retain the above copyright |
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18 | * notice, this list of conditions, and the following disclaimer. |
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19 | * |
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20 | * 2. Redistributions in binary form must reproduce the above copyright |
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21 | * notice, this list of conditions, and the disclaimer that follows |
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22 | * these conditions in the documentation and/or other materials |
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23 | * provided with the distribution. |
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24 | * |
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25 | * 3. The name "Jaxen" must not be used to endorse or promote products |
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26 | * derived from this software without prior written permission. For |
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27 | * written permission, please contact license@jaxen.org. |
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28 | * |
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29 | * 4. Products derived from this software may not be called "Jaxen", nor |
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30 | * may "Jaxen" appear in their name, without prior written permission |
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31 | * from the Jaxen Project Management (pm@jaxen.org). |
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32 | * |
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33 | * In addition, we request (but do not require) that you include in the |
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34 | * end-user documentation provided with the redistribution and/or in the |
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35 | * software itself an acknowledgement equivalent to the following: |
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36 | * "This product includes software developed by the |
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37 | * Jaxen Project <http://www.jaxen.org/>." |
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38 | * Alternatively, the acknowledgment may be graphical using the logos |
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39 | * available at http://www.jaxen.org/ |
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40 | * |
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41 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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42 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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43 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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44 | * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT |
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45 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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46 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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47 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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48 | * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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49 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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50 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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51 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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52 | * SUCH DAMAGE. |
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53 | * |
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54 | * ==================================================================== |
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55 | * This software consists of voluntary contributions made by many |
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56 | * individuals on behalf of the Jaxen Project and was originally |
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57 | * created by bob mcwhirter <bob@werken.com> and |
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58 | * James Strachan <jstrachan@apache.org>. For more information on the |
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59 | * Jaxen Project, please see <http://www.jaxen.org/>. |
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60 | * |
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61 | * $Id: PrecedingAxisIterator.java,v 1.8 2005/07/24 11:51:14 elharo Exp $ |
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62 | */ |
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63 | ||
64 | import org.jaxen.JaxenConstants; |
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65 | import org.jaxen.JaxenRuntimeException; |
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66 | import org.jaxen.Navigator; |
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67 | import org.jaxen.UnsupportedAxisException; |
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68 | ||
69 | import java.util.ArrayList; |
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70 | import java.util.Iterator; |
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71 | import java.util.ListIterator; |
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72 | import java.util.NoSuchElementException; |
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73 | ||
74 | /** |
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75 | * This implementation of 'preceding' works like so: |
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76 | * the preceding axis includes preceding-siblings of this node and their |
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77 | * descendants. Also, for each ancestor node of this node, it includes |
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78 | * all preceding-siblings of that ancestor, and their descendants. Finally, it |
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79 | * includes the ancestor nodes themselves. |
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80 | * <p/> |
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81 | * The reversed descendant-or-self axes that are required are calculated using a |
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82 | * stack of reversed 'child-or-self' axes. When asked for a node, it is always taken |
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83 | * from a child-or-self axis. If it was the last node on that axis, the node is returned. |
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84 | * Otherwise, this axis is pushed on the stack, and the process is repeated with the child-or-self |
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85 | * of the node. Eventually this recurses down to the last descendant of any node, then works |
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86 | * back up to the root. |
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87 | * <p/> |
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88 | * I reckon most object models could provide a faster implementation of the reversed |
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89 | * 'children-or-self' used here. |
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90 | */ |
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91 | public class PrecedingAxisIterator implements Iterator |
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92 | { |
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93 | private Iterator ancestorOrSelf; |
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94 | private Iterator precedingSibling; |
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95 | private ListIterator childrenOrSelf; |
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96 | private ArrayList stack; |
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97 | ||
98 | private Navigator navigator; |
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99 | ||
100 | public PrecedingAxisIterator(Object contextNode, |
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101 | Navigator navigator) throws UnsupportedAxisException |
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102 | 474 | { |
103 | 474 | this.navigator = navigator; |
104 | 474 | this.ancestorOrSelf = navigator.getAncestorOrSelfAxisIterator(contextNode); |
105 | 474 | this.precedingSibling = JaxenConstants.EMPTY_ITERATOR; |
106 | 474 | this.childrenOrSelf = JaxenConstants.EMPTY_LIST_ITERATOR; |
107 | 474 | this.stack = new ArrayList(); |
108 | 474 | } |
109 | ||
110 | ||
111 | public boolean hasNext() |
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112 | { |
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113 | try |
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114 | { |
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115 | 5352 | while (!childrenOrSelf.hasPrevious()) |
116 | { |
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117 | 2022 | if (stack.isEmpty()) |
118 | { |
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119 | 2418 | while (!precedingSibling.hasNext()) |
120 | { |
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121 | 1866 | if (!ancestorOrSelf.hasNext()) |
122 | { |
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123 | 468 | return false; |
124 | } |
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125 | 1398 | Object contextNode = ancestorOrSelf.next(); |
126 | 1398 | precedingSibling = new PrecedingSiblingAxisIterator(contextNode, navigator); |
127 | } |
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128 | 552 | Object node = precedingSibling.next(); |
129 | 552 | childrenOrSelf = childrenOrSelf(node); |
130 | } |
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131 | else |
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132 | { |
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133 | 1002 | childrenOrSelf = (ListIterator) stack.remove(stack.size()-1); |
134 | } |
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135 | } |
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136 | 3330 | return true; |
137 | } |
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138 | 0 | catch (UnsupportedAxisException e) |
139 | { |
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140 | 0 | throw new JaxenRuntimeException(e); |
141 | } |
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142 | } |
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143 | ||
144 | private ListIterator childrenOrSelf(Object node) |
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145 | { |
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146 | try |
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147 | { |
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148 | 1554 | ArrayList reversed = new ArrayList(); |
149 | 1554 | reversed.add(node); |
150 | 1554 | Iterator childAxisIterator = navigator.getChildAxisIterator(node); |
151 | 1554 | if (childAxisIterator != null) |
152 | { |
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153 | 2556 | while (childAxisIterator.hasNext()) |
154 | { |
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155 | 1002 | reversed.add(childAxisIterator.next()); |
156 | } |
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157 | } |
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158 | 1554 | return reversed.listIterator(reversed.size()); |
159 | } |
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160 | 0 | catch (UnsupportedAxisException e) |
161 | { |
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162 | 0 | throw new JaxenRuntimeException(e); |
163 | } |
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164 | } |
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165 | ||
166 | public Object next() throws NoSuchElementException |
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167 | { |
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168 | 1560 | if (!hasNext()) |
169 | { |
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170 | 6 | throw new NoSuchElementException(); |
171 | } |
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172 | while (true) |
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173 | { |
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174 | 2556 | Object result = childrenOrSelf.previous(); |
175 | 2556 | if (childrenOrSelf.hasPrevious()) |
176 | { |
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177 | // if this isn't 'self' construct 'descendant-or-self' |
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178 | 1002 | stack.add(childrenOrSelf); |
179 | 1002 | childrenOrSelf = childrenOrSelf(result); |
180 | 1002 | continue; |
181 | } |
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182 | 1554 | return result; |
183 | } |
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184 | } |
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185 | ||
186 | ||
187 | public void remove() throws UnsupportedOperationException |
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188 | { |
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189 | 6 | throw new UnsupportedOperationException(); |
190 | } |
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191 | } |