Source for org.w3c.dom.ls.LSParserFilter

   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: }