1 /* 2 * Copyright (c) 2004 World Wide Web Consortium, 3 * 4 * (Massachusetts Institute of Technology, European Research Consortium for 5 * Informatics and Mathematics, Keio University). All Rights Reserved. This 6 * work is distributed under the W3C(r) Software License [1] in the hope that 7 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied 8 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 9 * 10 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231 11 */ 12 13 package org.w3c.dom.ls; 14 15 import org.w3c.dom.Element; 16 import org.w3c.dom.Node; 17 18 /** 19 * <code>LSParserFilter</code>s provide applications the ability to examine 20 * nodes as they are being constructed while parsing. As each node is 21 * examined, it may be modified or removed, or the entire parse may be 22 * terminated early. 23 * <p> At the time any of the filter methods are called by the parser, the 24 * owner Document and DOMImplementation objects exist and are accessible. 25 * The document element is never passed to the <code>LSParserFilter</code> 26 * methods, i.e. it is not possible to filter out the document element. 27 * <code>Document</code>, <code>DocumentType</code>, <code>Notation</code>, 28 * <code>Entity</code>, and <code>Attr</code> nodes are never passed to the 29 * <code>acceptNode</code> method on the filter. The child nodes of an 30 * <code>EntityReference</code> node are passed to the filter if the 31 * parameter "<a href='http://www.w3.org/TR/DOM-Level-3-Core/core.html#parameter-entities'> 32 * entities</a>" is set to <code>false</code>. Note that, as described by the parameter "<a href='http://www.w3.org/TR/DOM-Level-3-Core/core.html#parameter-entities'> 33 * entities</a>", unexpanded entity reference nodes are never discarded and are always 34 * passed to the filter. 35 * <p> All validity checking while parsing a document occurs on the source 36 * document as it appears on the input stream, not on the DOM document as it 37 * is built in memory. With filters, the document in memory may be a subset 38 * of the document on the stream, and its validity may have been affected by 39 * the filtering. 40 * <p> All default attributes must be present on elements when the elements 41 * are passed to the filter methods. All other default content must be 42 * passed to the filter methods. 43 * <p> DOM applications must not raise exceptions in a filter. The effect of 44 * throwing exceptions from a filter is DOM implementation dependent. 45 * <p>See also the <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407'>Document Object Model (DOM) Level 3 Load 46 and Save Specification</a>. 47 */ 48 public interface LSParserFilter { 49 // Constants returned by startElement and acceptNode 50 /** 51 * Accept the node. 52 */ 53 public static final short FILTER_ACCEPT = 1; 54 /** 55 * Reject the node and its children. 56 */ 57 public static final short FILTER_REJECT = 2; 58 /** 59 * Skip this single node. The children of this node will still be 60 * considered. 61 */ 62 public static final short FILTER_SKIP = 3; 63 /** 64 * Interrupt the normal processing of the document. 65 */ 66 public static final short FILTER_INTERRUPT = 4; 67 68 /** 69 * The parser will call this method after each <code>Element</code> start 70 * tag has been scanned, but before the remainder of the 71 * <code>Element</code> is processed. The intent is to allow the 72 * element, including any children, to be efficiently skipped. Note that 73 * only element nodes are passed to the <code>startElement</code> 74 * function. 75 * <br>The element node passed to <code>startElement</code> for filtering 76 * will include all of the Element's attributes, but none of the 77 * children nodes. The Element may not yet be in place in the document 78 * being constructed (it may not have a parent node.) 79 * <br>A <code>startElement</code> filter function may access or change 80 * the attributes for the Element. Changing Namespace declarations will 81 * have no effect on namespace resolution by the parser. 82 * <br>For efficiency, the Element node passed to the filter may not be 83 * the same one as is actually placed in the tree if the node is 84 * accepted. And the actual node (node object identity) may be reused 85 * during the process of reading in and filtering a document. 86 * @param elementArg The newly encountered element. At the time this 87 * method is called, the element is incomplete - it will have its 88 * attributes, but no children. 89 * @return 90 * <ul> 91 * <li> <code>FILTER_ACCEPT</code> if the <code>Element</code> should 92 * be included in the DOM document being built. 93 * </li> 94 * <li> 95 * <code>FILTER_REJECT</code> if the <code>Element</code> and all of 96 * its children should be rejected. 97 * </li> 98 * <li> <code>FILTER_SKIP</code> if the 99 * <code>Element</code> should be skipped. All of its children are 100 * inserted in place of the skipped <code>Element</code> node. 101 * </li> 102 * <li> 103 * <code>FILTER_INTERRUPT</code> if the filter wants to stop the 104 * processing of the document. Interrupting the processing of the 105 * document does no longer guarantee that the resulting DOM tree is 106 * XML well-formed. The <code>Element</code> is rejected. 107 * </li> 108 * </ul> Returning 109 * any other values will result in unspecified behavior. 110 */ 111 public short startElement(Element elementArg); 112 113 /** 114 * This method will be called by the parser at the completion of the 115 * parsing of each node. The node and all of its descendants will exist 116 * and be complete. The parent node will also exist, although it may be 117 * incomplete, i.e. it may have additional children that have not yet 118 * been parsed. Attribute nodes are never passed to this function. 119 * <br>From within this method, the new node may be freely modified - 120 * children may be added or removed, text nodes modified, etc. The state 121 * of the rest of the document outside this node is not defined, and the 122 * affect of any attempt to navigate to, or to modify any other part of 123 * the document is undefined. 124 * <br>For validating parsers, the checks are made on the original 125 * document, before any modification by the filter. No validity checks 126 * are made on any document modifications made by the filter. 127 * <br>If this new node is rejected, the parser might reuse the new node 128 * and any of its descendants. 129 * @param nodeArg The newly constructed element. At the time this method 130 * is called, the element is complete - it has all of its children 131 * (and their children, recursively) and attributes, and is attached 132 * as a child to its parent. 133 * @return 134 * <ul> 135 * <li> <code>FILTER_ACCEPT</code> if this <code>Node</code> should 136 * be included in the DOM document being built. 137 * </li> 138 * <li> 139 * <code>FILTER_REJECT</code> if the <code>Node</code> and all of its 140 * children should be rejected. 141 * </li> 142 * <li> <code>FILTER_SKIP</code> if the 143 * <code>Node</code> should be skipped and the <code>Node</code> 144 * should be replaced by all the children of the <code>Node</code>. 145 * </li> 146 * <li> 147 * <code>FILTER_INTERRUPT</code> if the filter wants to stop the 148 * processing of the document. Interrupting the processing of the 149 * document does no longer guarantee that the resulting DOM tree is 150 * XML well-formed. The <code>Node</code> is accepted and will be the 151 * last completely parsed node. 152 * </li> 153 * </ul> 154 */ 155 public short acceptNode(Node nodeArg); 156 157 /** 158 * Tells the <code>LSParser</code> what types of nodes to show to the 159 * method <code>LSParserFilter.acceptNode</code>. If a node is not shown 160 * to the filter using this attribute, it is automatically included in 161 * the DOM document being built. See <code>NodeFilter</code> for 162 * definition of the constants. The constants <code>SHOW_ATTRIBUTE</code> 163 * , <code>SHOW_DOCUMENT</code>, <code>SHOW_DOCUMENT_TYPE</code>, 164 * <code>SHOW_NOTATION</code>, <code>SHOW_ENTITY</code>, and 165 * <code>SHOW_DOCUMENT_FRAGMENT</code> are meaningless here. Those nodes 166 * will never be passed to <code>LSParserFilter.acceptNode</code>. 167 * <br> The constants used here are defined in [<a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113'>DOM Level 2 Traversal and Range</a>] 168 * . 169 */ 170 public int getWhatToShow(); 171 172 } 173
