1 // SAX default handler base class.
2 // http://www.saxproject.org
3 // No warranty; no copyright -- use this as you will.
4 // $Id: HandlerBase.java 226184 2005-04-08 10:53:24Z neeraj $
5
6 package org.xml.sax;
7
8 /**
9 * Default base class for handlers.
10 *
11 * <blockquote>
12 * <em>This module, both source code and documentation, is in the
13 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
14 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
15 * for further information.
16 * </blockquote>
17 *
18 * <p>This class implements the default behaviour for four SAX1
19 * interfaces: EntityResolver, DTDHandler, DocumentHandler,
20 * and ErrorHandler. It is now obsolete, but is included in SAX2 to
21 * support legacy SAX1 applications. SAX2 applications should use
22 * the {@link org.xml.sax.helpers.DefaultHandler DefaultHandler}
23 * class instead.</p>
24 *
25 * <p>Application writers can extend this class when they need to
26 * implement only part of an interface; parser writers can
27 * instantiate this class to provide default handlers when the
28 * application has not supplied its own.</p>
29 *
30 * <p>Note that the use of this class is optional.</p>
31 *
32 * @deprecated This class works with the deprecated
33 * {@link org.xml.sax.DocumentHandler DocumentHandler}
34 * interface. It has been replaced by the SAX2
35 * {@link org.xml.sax.helpers.DefaultHandler DefaultHandler}
36 * class.
37 * @since SAX 1.0
38 * @author David Megginson
39 * @version 2.0.1 (sax2r2)
40 * @see org.xml.sax.EntityResolver
41 * @see org.xml.sax.DTDHandler
42 * @see org.xml.sax.DocumentHandler
43 * @see org.xml.sax.ErrorHandler
44 */
45 public class HandlerBase
46 implements EntityResolver, DTDHandler, DocumentHandler, ErrorHandler
47 {
48
49
50 ////////////////////////////////////////////////////////////////////
51 // Default implementation of the EntityResolver interface.
52 ////////////////////////////////////////////////////////////////////
53
54 /**
55 * Resolve an external entity.
56 *
57 * <p>Always return null, so that the parser will use the system
58 * identifier provided in the XML document. This method implements
59 * the SAX default behaviour: application writers can override it
60 * in a subclass to do special translations such as catalog lookups
61 * or URI redirection.</p>
62 *
63 * @param publicId The public identifer, or null if none is
64 * available.
65 * @param systemId The system identifier provided in the XML
66 * document.
67 * @return The new input source, or null to require the
68 * default behaviour.
69 * @exception org.xml.sax.SAXException Any SAX exception, possibly
70 * wrapping another exception.
71 * @see org.xml.sax.EntityResolver#resolveEntity
72 */
73 public InputSource resolveEntity (String publicId, String systemId)
74 throws SAXException
75 {
76 return null;
77 }
78
79
80
81 ////////////////////////////////////////////////////////////////////
82 // Default implementation of DTDHandler interface.
83 ////////////////////////////////////////////////////////////////////
84
85
86 /**
87 * Receive notification of a notation declaration.
88 *
89 * <p>By default, do nothing. Application writers may override this
90 * method in a subclass if they wish to keep track of the notations
91 * declared in a document.</p>
92 *
93 * @param name The notation name.
94 * @param publicId The notation public identifier, or null if not
95 * available.
96 * @param systemId The notation system identifier.
97 * @see org.xml.sax.DTDHandler#notationDecl
98 */
99 public void notationDecl (String name, String publicId, String systemId)
100 {
101 // no op
102 }
103
104
105 /**
106 * Receive notification of an unparsed entity declaration.
107 *
108 * <p>By default, do nothing. Application writers may override this
109 * method in a subclass to keep track of the unparsed entities
110 * declared in a document.</p>
111 *
112 * @param name The entity name.
113 * @param publicId The entity public identifier, or null if not
114 * available.
115 * @param systemId The entity system identifier.
116 * @param notationName The name of the associated notation.
117 * @see org.xml.sax.DTDHandler#unparsedEntityDecl
118 */
119 public void unparsedEntityDecl (String name, String publicId,
120 String systemId, String notationName)
121 {
122 // no op
123 }
124
125
126
127 ////////////////////////////////////////////////////////////////////
128 // Default implementation of DocumentHandler interface.
129 ////////////////////////////////////////////////////////////////////
130
131
132 /**
133 * Receive a Locator object for document events.
134 *
135 * <p>By default, do nothing. Application writers may override this
136 * method in a subclass if they wish to store the locator for use
137 * with other document events.</p>
138 *
139 * @param locator A locator for all SAX document events.
140 * @see org.xml.sax.DocumentHandler#setDocumentLocator
141 * @see org.xml.sax.Locator
142 */
143 public void setDocumentLocator (Locator locator)
144 {
145 // no op
146 }
147
148
149 /**
150 * Receive notification of the beginning of the document.
151 *
152 * <p>By default, do nothing. Application writers may override this
153 * method in a subclass to take specific actions at the beginning
154 * of a document (such as allocating the root node of a tree or
155 * creating an output file).</p>
156 *
157 * @exception org.xml.sax.SAXException Any SAX exception, possibly
158 * wrapping another exception.
159 * @see org.xml.sax.DocumentHandler#startDocument
160 */
161 public void startDocument ()
162 throws SAXException
163 {
164 // no op
165 }
166
167
168 /**
169 * Receive notification of the end of the document.
170 *
171 * <p>By default, do nothing. Application writers may override this
172 * method in a subclass to take specific actions at the beginning
173 * of a document (such as finalising a tree or closing an output
174 * file).</p>
175 *
176 * @exception org.xml.sax.SAXException Any SAX exception, possibly
177 * wrapping another exception.
178 * @see org.xml.sax.DocumentHandler#endDocument
179 */
180 public void endDocument ()
181 throws SAXException
182 {
183 // no op
184 }
185
186
187 /**
188 * Receive notification of the start of an element.
189 *
190 * <p>By default, do nothing. Application writers may override this
191 * method in a subclass to take specific actions at the start of
192 * each element (such as allocating a new tree node or writing
193 * output to a file).</p>
194 *
195 * @param name The element type name.
196 * @param attributes The specified or defaulted attributes.
197 * @exception org.xml.sax.SAXException Any SAX exception, possibly
198 * wrapping another exception.
199 * @see org.xml.sax.DocumentHandler#startElement
200 */
201 public void startElement (String name, AttributeList attributes)
202 throws SAXException
203 {
204 // no op
205 }
206
207
208 /**
209 * Receive notification of the end of an element.
210 *
211 * <p>By default, do nothing. Application writers may override this
212 * method in a subclass to take specific actions at the end of
213 * each element (such as finalising a tree node or writing
214 * output to a file).</p>
215 *
216 * @param name the element name
217 * @exception org.xml.sax.SAXException Any SAX exception, possibly
218 * wrapping another exception.
219 * @see org.xml.sax.DocumentHandler#endElement
220 */
221 public void endElement (String name)
222 throws SAXException
223 {
224 // no op
225 }
226
227
228 /**
229 * Receive notification of character data inside an element.
230 *
231 * <p>By default, do nothing. Application writers may override this
232 * method to take specific actions for each chunk of character data
233 * (such as adding the data to a node or buffer, or printing it to
234 * a file).</p>
235 *
236 * @param ch The characters.
237 * @param start The start position in the character array.
238 * @param length The number of characters to use from the
239 * character array.
240 * @exception org.xml.sax.SAXException Any SAX exception, possibly
241 * wrapping another exception.
242 * @see org.xml.sax.DocumentHandler#characters
243 */
244 public void characters (char ch[], int start, int length)
245 throws SAXException
246 {
247 // no op
248 }
249
250
251 /**
252 * Receive notification of ignorable whitespace in element content.
253 *
254 * <p>By default, do nothing. Application writers may override this
255 * method to take specific actions for each chunk of ignorable
256 * whitespace (such as adding data to a node or buffer, or printing
257 * it to a file).</p>
258 *
259 * @param ch The whitespace characters.
260 * @param start The start position in the character array.
261 * @param length The number of characters to use from the
262 * character array.
263 * @exception org.xml.sax.SAXException Any SAX exception, possibly
264 * wrapping another exception.
265 * @see org.xml.sax.DocumentHandler#ignorableWhitespace
266 */
267 public void ignorableWhitespace (char ch[], int start, int length)
268 throws SAXException
269 {
270 // no op
271 }
272
273
274 /**
275 * Receive notification of a processing instruction.
276 *
277 * <p>By default, do nothing. Application writers may override this
278 * method in a subclass to take specific actions for each
279 * processing instruction, such as setting status variables or
280 * invoking other methods.</p>
281 *
282 * @param target The processing instruction target.
283 * @param data The processing instruction data, or null if
284 * none is supplied.
285 * @exception org.xml.sax.SAXException Any SAX exception, possibly
286 * wrapping another exception.
287 * @see org.xml.sax.DocumentHandler#processingInstruction
288 */
289 public void processingInstruction (String target, String data)
290 throws SAXException
291 {
292 // no op
293 }
294
295
296
297 ////////////////////////////////////////////////////////////////////
298 // Default implementation of the ErrorHandler interface.
299 ////////////////////////////////////////////////////////////////////
300
301
302 /**
303 * Receive notification of a parser warning.
304 *
305 * <p>The default implementation does nothing. Application writers
306 * may override this method in a subclass to take specific actions
307 * for each warning, such as inserting the message in a log file or
308 * printing it to the console.</p>
309 *
310 * @param e The warning information encoded as an exception.
311 * @exception org.xml.sax.SAXException Any SAX exception, possibly
312 * wrapping another exception.
313 * @see org.xml.sax.ErrorHandler#warning
314 * @see org.xml.sax.SAXParseException
315 */
316 public void warning (SAXParseException e)
317 throws SAXException
318 {
319 // no op
320 }
321
322
323 /**
324 * Receive notification of a recoverable parser error.
325 *
326 * <p>The default implementation does nothing. Application writers
327 * may override this method in a subclass to take specific actions
328 * for each error, such as inserting the message in a log file or
329 * printing it to the console.</p>
330 *
331 * @param e The warning information encoded as an exception.
332 * @exception org.xml.sax.SAXException Any SAX exception, possibly
333 * wrapping another exception.
334 * @see org.xml.sax.ErrorHandler#warning
335 * @see org.xml.sax.SAXParseException
336 */
337 public void error (SAXParseException e)
338 throws SAXException
339 {
340 // no op
341 }
342
343
344 /**
345 * Report a fatal XML parsing error.
346 *
347 * <p>The default implementation throws a SAXParseException.
348 * Application writers may override this method in a subclass if
349 * they need to take specific actions for each fatal error (such as
350 * collecting all of the errors into a single report): in any case,
351 * the application must stop all regular processing when this
352 * method is invoked, since the document is no longer reliable, and
353 * the parser may no longer report parsing events.</p>
354 *
355 * @param e The error information encoded as an exception.
356 * @exception org.xml.sax.SAXException Any SAX exception, possibly
357 * wrapping another exception.
358 * @see org.xml.sax.ErrorHandler#fatalError
359 * @see org.xml.sax.SAXParseException
360 */
361 public void fatalError (SAXParseException e)
362 throws SAXException
363 {
364 throw e;
365 }
366
367 }
368
369 // end of HandlerBase.java