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      */
startDTD(String name, String publicId, String systemId)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      */
endDTD()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      */
startEntity(String name)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      */
endEntity(String name)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      */
startCDATA()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      */
endCDATA()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      */
comment(char ch[], int start, int length)207     public abstract void comment (char ch[], int start, int length)
208     throws SAXException;
209 
210 }
211 
212 // end of LexicalHandler.java
213