1 // LexicalHandler.java - optional handler for lexical parse events.
2 // http://www.saxproject.org
3 // Public Domain: no warranty.
4 // $Id: LexicalHandler.java 226184 2005-04-08 10:53:24Z neeraj $
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