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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.Node; 16: import org.w3c.dom.Element; 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: }