1 /*
2 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 * questions.
24 */
25
26 // ContentHandler.java - handle main document content.
27 // http://www.saxproject.org
28 // Written by David Megginson
29 // NO WARRANTY! This class is in the public domain.
30 // $Id: ContentHandler.java,v 1.2 2004/11/03 22:44:51 jsuttor Exp $
31
32 package org.xml.sax;
33
34
35 /**
36 * Receive notification of the logical content of a document.
37 *
38 * <blockquote>
39 * <em>This module, both source code and documentation, is in the
40 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
41 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
42 * for further information.
43 * </blockquote>
44 *
45 * <p>This is the main interface that most SAX applications
46 * implement: if the application needs to be informed of basic parsing
47 * events, it implements this interface and registers an instance with
48 * the SAX parser using the {@link org.xml.sax.XMLReader#setContentHandler
49 * setContentHandler} method. The parser uses the instance to report
50 * basic document-related events like the start and end of elements
51 * and character data.</p>
52 *
53 * <p>The order of events in this interface is very important, and
54 * mirrors the order of information in the document itself. For
55 * example, all of an element's content (character data, processing
56 * instructions, and/or subelements) will appear, in order, between
57 * the startElement event and the corresponding endElement event.</p>
58 *
59 * <p>This interface is similar to the now-deprecated SAX 1.0
60 * DocumentHandler interface, but it adds support for Namespaces
61 * and for reporting skipped entities (in non-validating XML
62 * processors).</p>
63 *
64 * <p>Implementors should note that there is also a
65 * <code>ContentHandler</code> class in the <code>java.net</code>
66 * package; that means that it's probably a bad idea to do</p>
67 *
68 * <pre>import java.net.*;
69 * import org.xml.sax.*;
70 * </pre>
71 *
72 * <p>In fact, "import ...*" is usually a sign of sloppy programming
73 * anyway, so the user should consider this a feature rather than a
74 * bug.</p>
75 *
76 * @since 1.4, SAX 2.0
77 * @author David Megginson
78 * @see org.xml.sax.XMLReader
79 * @see org.xml.sax.DTDHandler
80 * @see org.xml.sax.ErrorHandler
81 */
82 public interface ContentHandler
83 {
84
85 /**
86 * Receive an object for locating the origin of SAX document events.
87 *
88 * <p>SAX parsers are strongly encouraged (though not absolutely
89 * required) to supply a locator: if it does so, it must supply
90 * the locator to the application by invoking this method before
91 * invoking any of the other methods in the ContentHandler
92 * interface.</p>
93 *
94 * <p>The locator allows the application to determine the end
95 * position of any document-related event, even if the parser is
96 * not reporting an error. Typically, the application will
97 * use this information for reporting its own errors (such as
98 * character content that does not match an application's
99 * business rules). The information returned by the locator
100 * is probably not sufficient for use with a search engine.</p>
101 *
102 * <p>Note that the locator will return correct information only
103 * during the invocation SAX event callbacks after
104 * {@link #startDocument startDocument} returns and before
105 * {@link #endDocument endDocument} is called. The
106 * application should not attempt to use it at any other time.</p>
107 *
108 * @param locator an object that can return the location of
109 * any SAX document event
110 * @see org.xml.sax.Locator
111 */
112 public void setDocumentLocator (Locator locator);
113
114
115 /**
116 * Receive notification of the beginning of a document.
117 *
118 * <p>The SAX parser will invoke this method only once, before any
119 * other event callbacks (except for {@link #setDocumentLocator
120 * setDocumentLocator}).</p>
121 *
122 * @throws org.xml.sax.SAXException any SAX exception, possibly
123 * wrapping another exception
124 * @see #endDocument
125 */
126 public void startDocument ()
127 throws SAXException;
128
129 /**
130 * Receives notification of the XML declaration.
131 *
132 * @implSpec
133 * The default implementation in the SAX API is to do nothing.
134 *
135 * @param version the version string as in the input document, null if not
136 * specified
137 * @param encoding the encoding string as in the input document, null if not
138 * specified
139 * @param standalone the standalone string as in the input document, null if
140 * not specified
141 *
142 * @throws SAXException if the application wants to report an error or
143 * interrupt the parsing process
144 *
145 * @since 14
146 */
147 default void declaration(String version, String encoding, String standalone)
148 throws SAXException
149 {
150 //no op
151 }
152
153 /**
154 * Receive notification of the end of a document.
155 *
156 * <p>
157 * This method is invoked by the parser to signal it has reached the end of
158 * the document after successfully completing the parsing process.
159 * After the event, the parser will return the control to the application.
160 *
161 * @apiNote In case of a fatal error, the parser may choose to stop the
162 * parsing process with a {@link SAXException}, in which case, this method
163 * will never be called. Refer to
164 * {@link ErrorHandler#fatalError(org.xml.sax.SAXParseException)}.
165 *
166 * @throws org.xml.sax.SAXException any SAX exception, possibly
167 * wrapping another exception
168 * @see #startDocument
169 */
170 public void endDocument()
171 throws SAXException;
172
173
174 /**
175 * Begin the scope of a prefix-URI Namespace mapping.
176 *
177 * <p>The information from this event is not necessary for
178 * normal Namespace processing: the SAX XML reader will
179 * automatically replace prefixes for element and attribute
180 * names when the <code>http://xml.org/sax/features/namespaces</code>
181 * feature is <var>true</var> (the default).</p>
182 *
183 * <p>There are cases, however, when applications need to
184 * use prefixes in character data or in attribute values,
185 * where they cannot safely be expanded automatically; the
186 * start/endPrefixMapping event supplies the information
187 * to the application to expand prefixes in those contexts
188 * itself, if necessary.</p>
189 *
190 * <p>Note that start/endPrefixMapping events are not
191 * guaranteed to be properly nested relative to each other:
192 * all startPrefixMapping events will occur immediately before the
193 * corresponding {@link #startElement startElement} event,
194 * and all {@link #endPrefixMapping endPrefixMapping}
195 * events will occur immediately after the corresponding
196 * {@link #endElement endElement} event,
197 * but their order is not otherwise
198 * guaranteed.</p>
199 *
200 * <p>There should never be start/endPrefixMapping events for the
201 * "xml" prefix, since it is predeclared and immutable.</p>
202 *
203 * @param prefix the Namespace prefix being declared.
204 * An empty string is used for the default element namespace,
205 * which has no prefix.
206 * @param uri the Namespace URI the prefix is mapped to
207 * @throws org.xml.sax.SAXException the client may throw
208 * an exception during processing
209 * @see #endPrefixMapping
210 * @see #startElement
211 */
212 public void startPrefixMapping (String prefix, String uri)
213 throws SAXException;
214
215
216 /**
217 * End the scope of a prefix-URI mapping.
218 *
219 * <p>See {@link #startPrefixMapping startPrefixMapping} for
220 * details. These events will always occur immediately after the
221 * corresponding {@link #endElement endElement} event, but the order of
222 * {@link #endPrefixMapping endPrefixMapping} events is not otherwise
223 * guaranteed.</p>
224 *
225 * @param prefix the prefix that was being mapped.
226 * This is the empty string when a default mapping scope ends.
227 * @throws org.xml.sax.SAXException the client may throw
228 * an exception during processing
229 * @see #startPrefixMapping
230 * @see #endElement
231 */
232 public void endPrefixMapping (String prefix)
233 throws SAXException;
234
235
236 /**
237 * Receive notification of the beginning of an element.
238 *
239 * <p>The Parser will invoke this method at the beginning of every
240 * element in the XML document; there will be a corresponding
241 * {@link #endElement endElement} event for every startElement event
242 * (even when the element is empty). All of the element's content will be
243 * reported, in order, before the corresponding endElement
244 * event.</p>
245 *
246 * <p>This event allows up to three name components for each
247 * element:</p>
248 *
249 * <ol>
250 * <li>the Namespace URI;</li>
251 * <li>the local name; and</li>
252 * <li>the qualified (prefixed) name.</li>
253 * </ol>
254 *
255 * <p>Any or all of these may be provided, depending on the
256 * values of the <var>http://xml.org/sax/features/namespaces</var>
257 * and the <var>http://xml.org/sax/features/namespace-prefixes</var>
258 * properties:</p>
259 *
260 * <ul>
261 * <li>the Namespace URI and local name are required when
262 * the namespaces property is <var>true</var> (the default), and are
263 * optional when the namespaces property is <var>false</var> (if one is
264 * specified, both must be);</li>
265 * <li>the qualified name is required when the namespace-prefixes property
266 * is <var>true</var>, and is optional when the namespace-prefixes property
267 * is <var>false</var> (the default).</li>
268 * </ul>
269 *
270 * <p>Note that the attribute list provided will contain only
271 * attributes with explicit values (specified or defaulted):
272 * #IMPLIED attributes will be omitted. The attribute list
273 * will contain attributes used for Namespace declarations
274 * (xmlns* attributes) only if the
275 * <code>http://xml.org/sax/features/namespace-prefixes</code>
276 * property is true (it is false by default, and support for a
277 * true value is optional).</p>
278 *
279 * <p>Like {@link #characters characters()}, attribute values may have
280 * characters that need more than one <code>char</code> value. </p>
281 *
282 * @param uri the Namespace URI, or the empty string if the
283 * element has no Namespace URI or if Namespace
284 * processing is not being performed
285 * @param localName the local name (without prefix), or the
286 * empty string if Namespace processing is not being
287 * performed
288 * @param qName the qualified name (with prefix), or the
289 * empty string if qualified names are not available
290 * @param atts the attributes attached to the element. If
291 * there are no attributes, it shall be an empty
292 * Attributes object. The value of this object after
293 * startElement returns is undefined
294 * @throws org.xml.sax.SAXException any SAX exception, possibly
295 * wrapping another exception
296 * @see #endElement
297 * @see org.xml.sax.Attributes
298 * @see org.xml.sax.helpers.AttributesImpl
299 */
300 public void startElement (String uri, String localName,
301 String qName, Attributes atts)
302 throws SAXException;
303
304
305 /**
306 * Receive notification of the end of an element.
307 *
308 * <p>The SAX parser will invoke this method at the end of every
309 * element in the XML document; there will be a corresponding
310 * {@link #startElement startElement} event for every endElement
311 * event (even when the element is empty).</p>
312 *
313 * <p>For information on the names, see startElement.</p>
314 *
315 * @param uri the Namespace URI, or the empty string if the
316 * element has no Namespace URI or if Namespace
317 * processing is not being performed
318 * @param localName the local name (without prefix), or the
319 * empty string if Namespace processing is not being
320 * performed
321 * @param qName the qualified XML name (with prefix), or the
322 * empty string if qualified names are not available
323 * @throws org.xml.sax.SAXException any SAX exception, possibly
324 * wrapping another exception
325 */
326 public void endElement (String uri, String localName,
327 String qName)
328 throws SAXException;
329
330
331 /**
332 * Receive notification of character data.
333 *
334 * <p>The Parser will call this method to report each chunk of
335 * character data. SAX parsers may return all contiguous character
336 * data in a single chunk, or they may split it into several
337 * chunks; however, all of the characters in any single event
338 * must come from the same external entity so that the Locator
339 * provides useful information.</p>
340 *
341 * <p>The application must not attempt to read from the array
342 * outside of the specified range.</p>
343 *
344 * <p>Individual characters may consist of more than one Java
345 * <code>char</code> value. There are two important cases where this
346 * happens, because characters can't be represented in just sixteen bits.
347 * In one case, characters are represented in a <em>Surrogate Pair</em>,
348 * using two special Unicode values. Such characters are in the so-called
349 * "Astral Planes", with a code point above U+FFFF. A second case involves
350 * composite characters, such as a base character combining with one or
351 * more accent characters. </p>
352 *
353 * <p> Your code should not assume that algorithms using
354 * <code>char</code>-at-a-time idioms will be working in character
355 * units; in some cases they will split characters. This is relevant
356 * wherever XML permits arbitrary characters, such as attribute values,
357 * processing instruction data, and comments as well as in data reported
358 * from this method. It's also generally relevant whenever Java code
359 * manipulates internationalized text; the issue isn't unique to XML.</p>
360 *
361 * <p>Note that some parsers will report whitespace in element
362 * content using the {@link #ignorableWhitespace ignorableWhitespace}
363 * method rather than this one (validating parsers <em>must</em>
364 * do so).</p>
365 *
366 * @param ch the characters from the XML document
367 * @param start the start position in the array
368 * @param length the number of characters to read from the array
369 * @throws org.xml.sax.SAXException any SAX exception, possibly
370 * wrapping another exception
371 * @see #ignorableWhitespace
372 * @see org.xml.sax.Locator
373 */
374 public void characters (char ch[], int start, int length)
375 throws SAXException;
376
377
378 /**
379 * Receive notification of ignorable whitespace in element content.
380 *
381 * <p>Validating Parsers must use this method to report each chunk
382 * of whitespace in element content (see the W3C XML 1.0
383 * recommendation, section 2.10): non-validating parsers may also
384 * use this method if they are capable of parsing and using
385 * content models.</p>
386 *
387 * <p>SAX parsers may return all contiguous whitespace in a single
388 * chunk, or they may split it into several chunks; however, all of
389 * the characters in any single event must come from the same
390 * external entity, so that the Locator provides useful
391 * information.</p>
392 *
393 * <p>The application must not attempt to read from the array
394 * outside of the specified range.</p>
395 *
396 * @param ch the characters from the XML document
397 * @param start the start position in the array
398 * @param length the number of characters to read from the array
399 * @throws org.xml.sax.SAXException any SAX exception, possibly
400 * wrapping another exception
401 * @see #characters
402 */
403 public void ignorableWhitespace (char ch[], int start, int length)
404 throws SAXException;
405
406
407 /**
408 * Receive notification of a processing instruction.
409 *
410 * <p>The Parser will invoke this method once for each processing
411 * instruction found: note that processing instructions may occur
412 * before or after the main document element.</p>
413 *
414 * <p>A SAX parser must never report an XML declaration (XML 1.0,
415 * section 2.8) or a text declaration (XML 1.0, section 4.3.1)
416 * using this method.</p>
417 *
418 * <p>Like {@link #characters characters()}, processing instruction
419 * data may have characters that need more than one <code>char</code>
420 * value. </p>
421 *
422 * @param target the processing instruction target
423 * @param data the processing instruction data, or null if
424 * none was supplied. The data does not include any
425 * whitespace separating it from the target
426 * @throws org.xml.sax.SAXException any SAX exception, possibly
427 * wrapping another exception
428 */
429 public void processingInstruction (String target, String data)
430 throws SAXException;
431
432
433 /**
434 * Receive notification of a skipped entity.
435 * This is not called for entity references within markup constructs
436 * such as element start tags or markup declarations. (The XML
437 * recommendation requires reporting skipped external entities.
438 * SAX also reports internal entity expansion/non-expansion, except
439 * within markup constructs.)
440 *
441 * <p>The Parser will invoke this method each time the entity is
442 * skipped. Non-validating processors may skip entities if they
443 * have not seen the declarations (because, for example, the
444 * entity was declared in an external DTD subset). All processors
445 * may skip external entities, depending on the values of the
446 * <code>http://xml.org/sax/features/external-general-entities</code>
447 * and the
448 * <code>http://xml.org/sax/features/external-parameter-entities</code>
449 * properties.</p>
450 *
451 * @param name the name of the skipped entity. If it is a
452 * parameter entity, the name will begin with '%', and if
453 * it is the external DTD subset, it will be the string
454 * "[dtd]"
455 * @throws org.xml.sax.SAXException any SAX exception, possibly
456 * wrapping another exception
457 */
458 public void skippedEntity (String name)
459 throws SAXException;
460 }
461
462 // end of ContentHandler.java