001// LexicalHandler.java - optional handler for lexical parse events. 002// http://www.saxproject.org 003// Public Domain: no warranty. 004// $Id: LexicalHandler.java,v 1.1 2004/12/23 22:38:42 mark Exp $ 005 006package org.xml.sax.ext; 007 008import org.xml.sax.SAXException; 009 010/** 011 * SAX2 extension handler for lexical events. 012 * 013 * <blockquote> 014 * <em>This module, both source code and documentation, is in the 015 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> 016 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> 017 * for further information. 018 * </blockquote> 019 * 020 * <p>This is an optional extension handler for SAX2 to provide 021 * lexical information about an XML document, such as comments 022 * and CDATA section boundaries. 023 * XML readers are not required to recognize this handler, and it 024 * is not part of core-only SAX2 distributions.</p> 025 * 026 * <p>The events in the lexical handler apply to the entire document, 027 * not just to the document element, and all lexical handler events 028 * must appear between the content handler's startDocument and 029 * endDocument events.</p> 030 * 031 * <p>To set the LexicalHandler for an XML reader, use the 032 * {@link org.xml.sax.XMLReader#setProperty setProperty} method 033 * with the property name 034 * <code>http://xml.org/sax/properties/lexical-handler</code> 035 * and an object implementing this interface (or null) as the value. 036 * If the reader does not report lexical events, it will throw a 037 * {@link org.xml.sax.SAXNotRecognizedException SAXNotRecognizedException} 038 * when you attempt to register the handler.</p> 039 * 040 * @since SAX 2.0 (extensions 1.0) 041 * @author David Megginson 042 * @version 2.0.1 (sax2r2) 043 */ 044public interface LexicalHandler 045{ 046 047 /** 048 * Report the start of DTD declarations, if any. 049 * 050 * <p>This method is intended to report the beginning of the 051 * DOCTYPE declaration; if the document has no DOCTYPE declaration, 052 * this method will not be invoked.</p> 053 * 054 * <p>All declarations reported through 055 * {@link org.xml.sax.DTDHandler DTDHandler} or 056 * {@link org.xml.sax.ext.DeclHandler DeclHandler} events must appear 057 * between the startDTD and {@link #endDTD endDTD} events. 058 * Declarations are assumed to belong to the internal DTD subset 059 * unless they appear between {@link #startEntity startEntity} 060 * and {@link #endEntity endEntity} events. Comments and 061 * processing instructions from the DTD should also be reported 062 * between the startDTD and endDTD events, in their original 063 * order of (logical) occurrence; they are not required to 064 * appear in their correct locations relative to DTDHandler 065 * or DeclHandler events, however.</p> 066 * 067 * <p>Note that the start/endDTD events will appear within 068 * the start/endDocument events from ContentHandler and 069 * before the first 070 * {@link org.xml.sax.ContentHandler#startElement startElement} 071 * event.</p> 072 * 073 * @param name The document type name. 074 * @param publicId The declared public identifier for the 075 * external DTD subset, or null if none was declared. 076 * @param systemId The declared system identifier for the 077 * external DTD subset, or null if none was declared. 078 * (Note that this is not resolved against the document 079 * base URI.) 080 * @exception SAXException The application may raise an 081 * exception. 082 * @see #endDTD 083 * @see #startEntity 084 */ 085 public abstract void startDTD (String name, String publicId, 086 String systemId) 087 throws SAXException; 088 089 090 /** 091 * Report the end of DTD declarations. 092 * 093 * <p>This method is intended to report the end of the 094 * DOCTYPE declaration; if the document has no DOCTYPE declaration, 095 * this method will not be invoked.</p> 096 * 097 * @exception SAXException The application may raise an exception. 098 * @see #startDTD 099 */ 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