1 // LexicalHandler.java - optional handler for lexical parse events. 2 // http://www.saxproject.org 3 // Public Domain: no warranty. 4 // $Id: LexicalHandler.java,v 1.5 2002/01/30 21:00:44 dbrownell Exp $ 5 6 package org.xml.sax.ext; 7 8 import org.xml.sax.SAXException; 9 10 /** 11 * SAX2 extension handler for lexical events. 12 * 13 * <blockquote> 14 * <em>This module, both source code and documentation, is in the 15 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> 16 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> 17 * for further information. 18 * </blockquote> 19 * 20 * <p>This is an optional extension handler for SAX2 to provide 21 * lexical information about an XML document, such as comments 22 * and CDATA section boundaries. 23 * XML readers are not required to recognize this handler, and it 24 * is not part of core-only SAX2 distributions.</p> 25 * 26 * <p>The events in the lexical handler apply to the entire document, 27 * not just to the document element, and all lexical handler events 28 * must appear between the content handler's startDocument and 29 * endDocument events.</p> 30 * 31 * <p>To set the LexicalHandler for an XML reader, use the 32 * {@link org.xml.sax.XMLReader#setProperty setProperty} method 33 * with the property name 34 * <code>http://xml.org/sax/properties/lexical-handler</code> 35 * and an object implementing this interface (or null) as the value. 36 * If the reader does not report lexical events, it will throw a 37 * {@link org.xml.sax.SAXNotRecognizedException SAXNotRecognizedException} 38 * when you attempt to register the handler.</p> 39 * 40 * @since SAX 2.0 (extensions 1.0) 41 * @author David Megginson 42 * @version 2.0.1 (sax2r2) 43 */ 44 public interface LexicalHandler 45 { 46 47 /** 48 * Report the start of DTD declarations, if any. 49 * 50 * <p>This method is intended to report the beginning of the 51 * DOCTYPE declaration; if the document has no DOCTYPE declaration, 52 * this method will not be invoked.</p> 53 * 54 * <p>All declarations reported through 55 * {@link org.xml.sax.DTDHandler DTDHandler} or 56 * {@link org.xml.sax.ext.DeclHandler DeclHandler} events must appear 57 * between the startDTD and {@link #endDTD endDTD} events. 58 * Declarations are assumed to belong to the internal DTD subset 59 * unless they appear between {@link #startEntity startEntity} 60 * and {@link #endEntity endEntity} events. Comments and 61 * processing instructions from the DTD should also be reported 62 * between the startDTD and endDTD events, in their original 63 * order of (logical) occurrence; they are not required to 64 * appear in their correct locations relative to DTDHandler 65 * or DeclHandler events, however.</p> 66 * 67 * <p>Note that the start/endDTD events will appear within 68 * the start/endDocument events from ContentHandler and 69 * before the first 70 * {@link org.xml.sax.ContentHandler#startElement startElement} 71 * event.</p> 72 * 73 * @param name The document type name. 74 * @param publicId The declared public identifier for the 75 * external DTD subset, or null if none was declared. 76 * @param systemId The declared system identifier for the 77 * external DTD subset, or null if none was declared. 78 * (Note that this is not resolved against the document 79 * base URI.) 80 * @exception SAXException The application may raise an 81 * exception. 82 * @see #endDTD 83 * @see #startEntity 84 */ 85 public abstract void startDTD (String name, String publicId, 86 String systemId) 87 throws SAXException; 88 89 90 /** 91 * Report the end of DTD declarations. 92 * 93 * <p>This method is intended to report the end of the 94 * DOCTYPE declaration; if the document has no DOCTYPE declaration, 95 * this method will not be invoked.</p> 96 * 97 * @exception SAXException The application may raise an exception. 98 * @see #startDTD 99 */ 100 public abstract void endDTD () 101 throws SAXException; 102 103 104 /** 105 * Report the beginning of some internal and external XML entities. 106 * 107 * <p>The reporting of parameter entities (including 108 * the external DTD subset) is optional, and SAX2 drivers that 109 * report LexicalHandler events may not implement it; you can use the 110 * <code 111 * >http://xml.org/sax/features/lexical-handler/parameter-entities</code> 112 * feature to query or control the reporting of parameter entities.</p> 113 * 114 * <p>General entities are reported with their regular names, 115 * parameter entities have '%' prepended to their names, and 116 * the external DTD subset has the pseudo-entity name "[dtd]".</p> 117 * 118 * <p>When a SAX2 driver is providing these events, all other 119 * events must be properly nested within start/end entity 120 * events. There is no additional requirement that events from 121 * {@link org.xml.sax.ext.DeclHandler DeclHandler} or 122 * {@link org.xml.sax.DTDHandler DTDHandler} be properly ordered.</p> 123 * 124 * <p>Note that skipped entities will be reported through the 125 * {@link org.xml.sax.ContentHandler#skippedEntity skippedEntity} 126 * event, which is part of the ContentHandler interface.</p> 127 * 128 * <p>Because of the streaming event model that SAX uses, some 129 * entity boundaries cannot be reported under any 130 * circumstances:</p> 131 * 132 * <ul> 133 * <li>general entities within attribute values</li> 134 * <li>parameter entities within declarations</li> 135 * </ul> 136 * 137 * <p>These will be silently expanded, with no indication of where 138 * the original entity boundaries were.</p> 139 * 140 * <p>Note also that the boundaries of character references (which 141 * are not really entities anyway) are not reported.</p> 142 * 143 * <p>All start/endEntity events must be properly nested. 144 * 145 * @param name The name of the entity. If it is a parameter 146 * entity, the name will begin with '%', and if it is the 147 * external DTD subset, it will be "[dtd]". 148 * @exception SAXException The application may raise an exception. 149 * @see #endEntity 150 * @see org.xml.sax.ext.DeclHandler#internalEntityDecl 151 * @see org.xml.sax.ext.DeclHandler#externalEntityDecl 152 */ 153 public abstract void startEntity (String name) 154 throws SAXException; 155 156 157 /** 158 * Report the end of an entity. 159 * 160 * @param name The name of the entity that is ending. 161 * @exception SAXException The application may raise an exception. 162 * @see #startEntity 163 */ 164 public abstract void endEntity (String name) 165 throws SAXException; 166 167 168 /** 169 * Report the start of a CDATA section. 170 * 171 * <p>The contents of the CDATA section will be reported through 172 * the regular {@link org.xml.sax.ContentHandler#characters 173 * characters} event; this event is intended only to report 174 * the boundary.</p> 175 * 176 * @exception SAXException The application may raise an exception. 177 * @see #endCDATA 178 */ 179 public abstract void startCDATA () 180 throws SAXException; 181 182 183 /** 184 * Report the end of a CDATA section. 185 * 186 * @exception SAXException The application may raise an exception. 187 * @see #startCDATA 188 */ 189 public abstract void endCDATA () 190 throws SAXException; 191 192 193 /** 194 * Report an XML comment anywhere in the document. 195 * 196 * <p>This callback will be used for comments inside or outside the 197 * document element, including comments in the external DTD 198 * subset (if read). Comments in the DTD must be properly 199 * nested inside start/endDTD and start/endEntity events (if 200 * used).</p> 201 * 202 * @param ch An array holding the characters in the comment. 203 * @param start The starting position in the array. 204 * @param length The number of characters to use from the array. 205 * @exception SAXException The application may raise an exception. 206 */ 207 public abstract void comment (char ch[], int start, int length) 208 throws SAXException; 209 210 } 211 212 // end of LexicalHandler.java 213
