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1 /*--
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2
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3 $Id: DescendantIterator.java,v 1.6 2007/11/10 05:28:58 jhunter Exp $
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4
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5 Copyright (C) 2000-2007 Jason Hunter & Brett McLaughlin.
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6 All rights reserved.
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7
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8 Redistribution and use in source and binary forms, with or without
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9 modification, are permitted provided that the following conditions
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10 are met:
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11
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12 1. Redistributions of source code must retain the above copyright
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13 notice, this list of conditions, and the following disclaimer.
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14
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15 2. Redistributions in binary form must reproduce the above copyright
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16 notice, this list of conditions, and the disclaimer that follows
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17 these conditions in the documentation and/or other materials
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18 provided with the distribution.
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19
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20 3. The name "JDOM" must not be used to endorse or promote products
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21 derived from this software without prior written permission. For
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22 written permission, please contact <request_AT_jdom_DOT_org>.
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23
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24 4. Products derived from this software may not be called "JDOM", nor
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25 may "JDOM" appear in their name, without prior written permission
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26 from the JDOM Project Management <request_AT_jdom_DOT_org>.
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27
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28 In addition, we request (but do not require) that you include in the
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29 end-user documentation provided with the redistribution and/or in the
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30 software itself an acknowledgement equivalent to the following:
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31 "This product includes software developed by the
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32 JDOM Project (http://www.jdom.org/)."
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33 Alternatively, the acknowledgment may be graphical using the logos
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34 available at http://www.jdom.org/images/logos.
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35
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36 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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37 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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38 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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39 DISCLAIMED. IN NO EVENT SHALL THE JDOM AUTHORS OR THE PROJECT
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40 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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41 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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42 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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43 USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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44 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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45 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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46 OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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47 SUCH DAMAGE.
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48
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49 This software consists of voluntary contributions made by many
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50 individuals on behalf of the JDOM Project and was originally
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51 created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
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52 Brett McLaughlin <brett_AT_jdom_DOT_org>. For more information
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53 on the JDOM Project, please see <http://www.jdom.org/>.
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54
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55 */
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56
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57 package org.jdom;
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58
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59 import java.util.*;
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60 import org.jdom.Content;
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61 import org.jdom.Element;
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62 import org.jdom.Parent;
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63
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64 /**
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65 * Traverse all a parent's descendants (all children at any level below
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66 * the parent).
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67 *
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68 * @author Bradley S. Huffman
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69 * @author Jason Hunter
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70 * @version $Revision: 1.6 $, $Date: 2007/11/10 05:28:58 $
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71 */
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72 class DescendantIterator implements Iterator {
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73
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74 private Iterator iterator;
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75 private Iterator nextIterator;
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76 private List stack = new ArrayList();
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77
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78 private static final String CVS_ID =
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79 "@(#) $RCSfile: DescendantIterator.java,v $ $Revision: 1.6 $ $Date: 2007/11/10 05:28:58 $ $Name: jdom_1_1_1 $";
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80
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81 /**
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82 * Iterator for the descendants of the supplied object.
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83 *
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84 * @param parent document or element whose descendants will be iterated
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85 */
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86 DescendantIterator(Parent parent) {
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87 if (parent == null) {
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88 throw new IllegalArgumentException("parent parameter was null");
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89 }
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90 this.iterator = parent.getContent().iterator();
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91 }
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92
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93 /**
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94 * Returns true> if the iteration has more {@link Content} descendants.
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95 *
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96 * @return true is the iterator has more descendants
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97 */
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98 public boolean hasNext() {
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99 if (iterator != null && iterator.hasNext()) return true;
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100 if (nextIterator != null && nextIterator.hasNext()) return true;
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101 if (stackHasAnyNext()) return true;
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102 return false;
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103 }
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104
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105 /**
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106 * Returns the next {@link Content} descendant.
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107 *
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108 * @return the next descendant
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109 */
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110 public Object next() {
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111 if (!hasNext()) {
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112 throw new NoSuchElementException();
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113 }
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114
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115 // If we need to descend, go for it and record where we are.
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116 // We do the shuffle here on the next next() call so remove() is easy
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117 // to code up.
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118 if (nextIterator != null) {
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119 push(iterator);
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120 iterator = nextIterator;
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121 nextIterator = null;
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122 }
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123
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124 // If this iterator is finished, try moving up the stack
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125 while (!iterator.hasNext()) {
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126 if (stack.size() > 0) {
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127 iterator = pop();
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128 }
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129 else {
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130 throw new NoSuchElementException("Somehow we lost our iterator");
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131 }
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132 }
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133
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134 Content child = (Content) iterator.next();
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135 if (child instanceof Element) {
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136 nextIterator = ((Element)child).getContent().iterator();
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137 }
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138 return child;
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139 }
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140
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141 /**
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142 * Detaches the last {@link org.jdom.Content} returned by the last call to
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143 * next from it's parent. <b>Note</b>: this <b>does not</b> affect
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144 * iteration and all children, siblings, and any node following the
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145 * removed node (in document order) will be visited.
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146 */
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147 public void remove() {
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148 iterator.remove();
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149 }
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150
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151 private Iterator pop() {
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152 int stackSize = stack.size();
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153 if (stackSize == 0) {
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154 throw new NoSuchElementException("empty stack");
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155 }
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156 return (Iterator) stack.remove(stackSize - 1);
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157 }
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158
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159 private void push(Iterator itr) {
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160 stack.add(itr);
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161 }
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162
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163 private boolean stackHasAnyNext() {
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164 int size = stack.size();
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165 for (int i = 0; i < size; i++) {
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166 Iterator itr = (Iterator) stack.get(i);
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167 if (itr.hasNext()) {
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168 return true;
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169 }
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170 }
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171 return false;
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172 }
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173 }
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