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| PruningElementStack.java | 0% | 0% | 0% | 0% |
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| 1 | /* | |
| 2 | * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved. | |
| 3 | * | |
| 4 | * This software is open source. | |
| 5 | * See the bottom of this file for the licence. | |
| 6 | */ | |
| 7 | ||
| 8 | package org.dom4j.io; | |
| 9 | ||
| 10 | import org.dom4j.Element; | |
| 11 | import org.dom4j.ElementHandler; | |
| 12 | ||
| 13 | /** | |
| 14 | * <p> | |
| 15 | * <code>PruningElementStack</code> is a stack of {@link Element}instances | |
| 16 | * which will prune the tree when a path expression is reached. This is useful | |
| 17 | * for parsing very large documents where children of the root element can be | |
| 18 | * processed individually rather than keeping them all in memory at the same | |
| 19 | * time. | |
| 20 | * </p> | |
| 21 | * | |
| 22 | * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a> | |
| 23 | * @version $Revision: 1.11 $ | |
| 24 | */ | |
| 25 | class PruningElementStack extends ElementStack { | |
| 26 | /** ElementHandler to call when pruning occurs */ | |
| 27 | private ElementHandler elementHandler; | |
| 28 | ||
| 29 | /** | |
| 30 | * the element name path which denotes the node to remove from its parent | |
| 31 | * when it is complete (i.e. when it is popped from the stack). The first | |
| 32 | * entry in the path will be a child of the root node | |
| 33 | */ | |
| 34 | private String[] path; | |
| 35 | ||
| 36 | /** | |
| 37 | * The level at which a path match can occur. We match when we have popped | |
| 38 | * the selected node so the and the lastElementIndex points to its parent so | |
| 39 | * this value should be path.length - 2 | |
| 40 | */ | |
| 41 | private int matchingElementIndex; | |
| 42 | ||
| 43 | 0 | public PruningElementStack(String[] path, ElementHandler elementHandler) { |
| 44 | 0 | this.path = path; |
| 45 | 0 | this.elementHandler = elementHandler; |
| 46 | 0 | checkPath(); |
| 47 | } | |
| 48 | ||
| 49 | 0 | public PruningElementStack(String[] path, ElementHandler elementHandler, |
| 50 | int defaultCapacity) { | |
| 51 | 0 | super(defaultCapacity); |
| 52 | 0 | this.path = path; |
| 53 | 0 | this.elementHandler = elementHandler; |
| 54 | 0 | checkPath(); |
| 55 | } | |
| 56 | ||
| 57 | 0 | public Element popElement() { |
| 58 | 0 | Element answer = super.popElement(); |
| 59 | ||
| 60 | 0 | if ((lastElementIndex == matchingElementIndex) |
| 61 | && (lastElementIndex >= 0)) { | |
| 62 | // we are popping the correct level in the tree | |
| 63 | // lets check if the path fits | |
| 64 | // | |
| 65 | // NOTE: this is an inefficient way of doing it - we could | |
| 66 | // maintain a history of which parts matched? | |
| 67 | 0 | if (validElement(answer, lastElementIndex + 1)) { |
| 68 | 0 | Element parent = null; |
| 69 | ||
| 70 | 0 | for (int i = 0; i <= lastElementIndex; i++) { |
| 71 | 0 | parent = stack[i]; |
| 72 | ||
| 73 | 0 | if (!validElement(parent, i)) { |
| 74 | 0 | parent = null; |
| 75 | ||
| 76 | 0 | break; |
| 77 | } | |
| 78 | } | |
| 79 | ||
| 80 | 0 | if (parent != null) { |
| 81 | 0 | pathMatches(parent, answer); |
| 82 | } | |
| 83 | } | |
| 84 | } | |
| 85 | ||
| 86 | 0 | return answer; |
| 87 | } | |
| 88 | ||
| 89 | 0 | protected void pathMatches(Element parent, Element selectedNode) { |
| 90 | 0 | elementHandler.onEnd(this); |
| 91 | 0 | parent.remove(selectedNode); |
| 92 | } | |
| 93 | ||
| 94 | 0 | protected boolean validElement(Element element, int index) { |
| 95 | 0 | String requiredName = path[index]; |
| 96 | 0 | String name = element.getName(); |
| 97 | ||
| 98 | 0 | if (requiredName == name) { |
| 99 | 0 | return true; |
| 100 | } | |
| 101 | ||
| 102 | 0 | if ((requiredName != null) && (name != null)) { |
| 103 | 0 | return requiredName.equals(name); |
| 104 | } | |
| 105 | ||
| 106 | 0 | return false; |
| 107 | } | |
| 108 | ||
| 109 | 0 | private void checkPath() { |
| 110 | 0 | if (path.length < 2) { |
| 111 | 0 | throw new RuntimeException("Invalid path of length: " + path.length |
| 112 | + " it must be greater than 2"); | |
| 113 | } | |
| 114 | ||
| 115 | 0 | matchingElementIndex = path.length - 2; |
| 116 | } | |
| 117 | } | |
| 118 | ||
| 119 | /* | |
| 120 | * Redistribution and use of this software and associated documentation | |
| 121 | * ("Software"), with or without modification, are permitted provided that the | |
| 122 | * following conditions are met: | |
| 123 | * | |
| 124 | * 1. Redistributions of source code must retain copyright statements and | |
| 125 | * notices. Redistributions must also contain a copy of this document. | |
| 126 | * | |
| 127 | * 2. Redistributions in binary form must reproduce the above copyright notice, | |
| 128 | * this list of conditions and the following disclaimer in the documentation | |
| 129 | * and/or other materials provided with the distribution. | |
| 130 | * | |
| 131 | * 3. The name "DOM4J" must not be used to endorse or promote products derived | |
| 132 | * from this Software without prior written permission of MetaStuff, Ltd. For | |
| 133 | * written permission, please contact dom4j-info@metastuff.com. | |
| 134 | * | |
| 135 | * 4. Products derived from this Software may not be called "DOM4J" nor may | |
| 136 | * "DOM4J" appear in their names without prior written permission of MetaStuff, | |
| 137 | * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd. | |
| 138 | * | |
| 139 | * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org | |
| 140 | * | |
| 141 | * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND | |
| 142 | * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 143 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 144 | * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE | |
| 145 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 146 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 147 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 148 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 149 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 150 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 151 | * POSSIBILITY OF SUCH DAMAGE. | |
| 152 | * | |
| 153 | * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved. | |
| 154 | */ |
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