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1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 // SAXCatalogReader.java - Read XML Catalog files
6
7 /*
8 * Copyright 2001-2004 The Apache Software Foundation or its licensors,
9 * as applicable.
10 *
11 * Licensed under the Apache License, Version 2.0 (the "License");
12 * you may not use this file except in compliance with the License.
13 * You may obtain a copy of the License at
14 *
15 * http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing, software
18 * distributed under the License is distributed on an "AS IS" BASIS,
19 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20 * See the License for the specific language governing permissions and
21 * limitations under the License.
22 */
23
24 package com.sun.org.apache.xml.internal.resolver.readers;
25
26 import java.util.Hashtable;
27 import java.io.IOException;
28 import java.io.FileNotFoundException;
29 import java.io.InputStream;
30 import java.net.URL;
31 import java.net.URLConnection;
32 import java.net.MalformedURLException;
33 import java.net.UnknownHostException;
34
35 import javax.xml.parsers.ParserConfigurationException;
36 import javax.xml.parsers.SAXParserFactory;
37 import javax.xml.parsers.SAXParser;
38
39 import org.xml.sax.AttributeList;
40 import org.xml.sax.Attributes;
41 import org.xml.sax.ContentHandler;
42 import org.xml.sax.DocumentHandler;
43 import org.xml.sax.EntityResolver;
44 import org.xml.sax.InputSource;
45 import org.xml.sax.Locator;
46 import org.xml.sax.Parser;
47 import org.xml.sax.SAXException;
48
49 import com.sun.org.apache.xml.internal.resolver.Catalog;
50 import com.sun.org.apache.xml.internal.resolver.CatalogManager;
51 import com.sun.org.apache.xml.internal.resolver.CatalogException;
52 import com.sun.org.apache.xml.internal.resolver.readers.CatalogReader;
53 import com.sun.org.apache.xml.internal.resolver.helpers.Debug;
54
55 /**
56 * A SAX-based CatalogReader.
57 *
58 * <p>This class is used to read XML Catalogs using the SAX. This reader
59 * has an advantage over the DOM-based reader in that it functions on
60 * the stream of SAX events. It has the disadvantage
61 * that it cannot look around in the tree.</p>
62 *
63 * <p>Since the choice of CatalogReaders (in the InputStream case) can only
64 * be made on the basis of MIME type, the following problem occurs: only
65 * one CatalogReader can exist for all XML mime types. In order to get
66 * around this problem, the SAXCatalogReader relies on a set of external
67 * CatalogParsers to actually build the catalog.</p>
68 *
69 * <p>The selection of CatalogParsers is made on the basis of the QName
70 * of the root element of the document.</p>
71 *
72 * @see Catalog
73 * @see CatalogReader
74 * @see SAXCatalogReader
75 * @see TextCatalogReader
76 * @see DOMCatalogParser
77 *
78 * @author Norman Walsh
79 * <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a>
80 *
81 */
82 public class SAXCatalogReader implements CatalogReader, ContentHandler, DocumentHandler {
83 /** The SAX Parser Factory */
84 protected SAXParserFactory parserFactory = null;
85
86 /** The SAX Parser Class */
87 protected String parserClass = null;
88
89 /**
90 * Mapping table from QNames to CatalogParser classes.
91 *
92 * <p>Each key in this hash table has the form "elementname"
93 * or "{namespaceuri}elementname". The former is used if the
94 * namespace URI is null.</p>
95 */
96 protected Hashtable namespaceMap = new Hashtable();
97
98 /** The parser in use for the current catalog. */
99 private SAXCatalogParser saxParser = null;
100
101 /** Set if something goes horribly wrong. It allows the class to
102 * ignore the rest of the events that are received.
103 */
104 private boolean abandonHope = false;
105
106 /** The Catalog that we're working for. */
107 private Catalog catalog;
108
109 /** Set the XML SAX Parser Factory.
110 */
111 public void setParserFactory(SAXParserFactory parserFactory) {
112 this.parserFactory = parserFactory;
113 }
114
115 /** Set the XML SAX Parser Class
116 */
117 public void setParserClass(String parserClass) {
118 this.parserClass = parserClass;
119 }
120
121 /** Get the parser factory currently in use. */
122 public SAXParserFactory getParserFactory() {
123 return parserFactory;
124 }
125
126 /** Get the parser class currently in use. */
127 public String getParserClass() {
128 return parserClass;
129 }
130
131 /** The debug class to use for this reader.
132 *
133 * This is a bit of a hack. Anyway, whenever we read for a catalog,
134 * we extract the debug object
135 * from the catalog's manager so that we can use it to print messages.
136 *
137 * In production, we don't really expect any messages so it doesn't
138 * really matter. But it's still a bit of a hack.
139 */
140 protected Debug debug = CatalogManager.getStaticManager().debug;
141
142 /** The constructor */
143 public SAXCatalogReader() {
144 parserFactory = null;
145 parserClass = null;
146 }
147
148 /** The constructor */
149 public SAXCatalogReader(SAXParserFactory parserFactory) {
150 this.parserFactory = parserFactory;
151 }
152
153 /** The constructor */
154 public SAXCatalogReader(String parserClass) {
155 this.parserClass = parserClass;
156 }
157
158 /** Set the SAXCatalogParser class for the given namespace/root
159 * element type.
160 */
161 public void setCatalogParser(String namespaceURI,
162 String rootElement,
163 String parserClass) {
164 if (namespaceURI == null) {
165 namespaceMap.put(rootElement, parserClass);
166 } else {
167 namespaceMap.put("{"+namespaceURI+"}"+rootElement, parserClass);
168 }
169 }
170
171 /** Get the SAXCatalogParser class for the given namespace/root
172 * element type.
173 */
174 public String getCatalogParser(String namespaceURI,
175 String rootElement) {
176 if (namespaceURI == null) {
177 return (String) namespaceMap.get(rootElement);
178 } else {
179 return (String) namespaceMap.get("{"+namespaceURI+"}"+rootElement);
180 }
181 }
182
183 /**
184 * Parse an XML Catalog file.
185 *
186 * @param catalog The catalog to which this catalog file belongs
187 * @param fileUrl The URL or filename of the catalog file to process
188 *
189 * @throws MalformedURLException Improper fileUrl
190 * @throws IOException Error reading catalog file
191 */
192 public void readCatalog(Catalog catalog, String fileUrl)
193 throws MalformedURLException, IOException,
194 CatalogException {
195
196 URL url = null;
197
198 try {
199 url = new URL(fileUrl);
200 } catch (MalformedURLException e) {
201 url = new URL("file:///" + fileUrl);
202 }
203
204 debug = catalog.getCatalogManager().debug;
205
206 try {
207 URLConnection urlCon = url.openConnection();
208 readCatalog(catalog, urlCon.getInputStream());
209 } catch (FileNotFoundException e) {
210 catalog.getCatalogManager().debug.message(1, "Failed to load catalog, file not found",
211 url.toString());
212 }
213 }
214
215 /**
216 * Parse an XML Catalog stream.
217 *
218 * @param catalog The catalog to which this catalog file belongs
219 * @param is The input stream from which the catalog will be read
220 *
221 * @throws MalformedURLException Improper fileUrl
222 * @throws IOException Error reading catalog file
223 * @throws CatalogException A Catalog exception
224 */
225 public void readCatalog(Catalog catalog, InputStream is)
226 throws IOException, CatalogException {
227
228 // Create an instance of the parser
229 if (parserFactory == null && parserClass == null) {
230 debug.message(1, "Cannot read SAX catalog without a parser");
231 throw new CatalogException(CatalogException.UNPARSEABLE);
232 }
233
234 debug = catalog.getCatalogManager().debug;
235 EntityResolver bResolver = catalog.getCatalogManager().getBootstrapResolver();
236
237 this.catalog = catalog;
238
239 try {
240 if (parserFactory != null) {
241 SAXParser parser = parserFactory.newSAXParser();
242 SAXParserHandler spHandler = new SAXParserHandler();
243 spHandler.setContentHandler(this);
244 if (bResolver != null) {
245 spHandler.setEntityResolver(bResolver);
246 }
247 parser.parse(new InputSource(is), spHandler);
248 } else {
249 Parser parser = (Parser) Class.forName(parserClass).newInstance();
250 parser.setDocumentHandler(this);
251 if (bResolver != null) {
252 parser.setEntityResolver(bResolver);
253 }
254 parser.parse(new InputSource(is));
255 }
256 } catch (ClassNotFoundException cnfe) {
257 throw new CatalogException(CatalogException.UNPARSEABLE);
258 } catch (IllegalAccessException iae) {
259 throw new CatalogException(CatalogException.UNPARSEABLE);
260 } catch (InstantiationException ie) {
261 throw new CatalogException(CatalogException.UNPARSEABLE);
262 } catch (ParserConfigurationException pce) {
263 throw new CatalogException(CatalogException.UNKNOWN_FORMAT);
264 } catch (SAXException se) {
265 Exception e = se.getException();
266 // FIXME: there must be a better way
267 UnknownHostException uhe = new UnknownHostException();
268 FileNotFoundException fnfe = new FileNotFoundException();
269 if (e != null) {
270 if (e.getClass() == uhe.getClass()) {
271 throw new CatalogException(CatalogException.PARSE_FAILED,
272 e.toString());
273 } else if (e.getClass() == fnfe.getClass()) {
274 throw new CatalogException(CatalogException.PARSE_FAILED,
275 e.toString());
276 }
277 }
278 throw new CatalogException(se);
279 }
280 }
281
282 // ----------------------------------------------------------------------
283 // Implement the SAX ContentHandler interface
284
285 /** The SAX <code>setDocumentLocator</code> method. Does nothing. */
286 public void setDocumentLocator (Locator locator) {
287 if (saxParser != null) {
288 saxParser.setDocumentLocator(locator);
289 }
290 }
291
292 /** The SAX <code>startDocument</code> method. Does nothing. */
293 public void startDocument () throws SAXException {
294 saxParser = null;
295 abandonHope = false;
296 return;
297 }
298
299 /** The SAX <code>endDocument</code> method. Does nothing. */
300 public void endDocument ()throws SAXException {
301 if (saxParser != null) {
302 saxParser.endDocument();
303 }
304 }
305
306 /**
307 * The SAX <code>startElement</code> method.
308 *
309 * <p>The catalog parser is selected based on the namespace of the
310 * first element encountered in the catalog.</p>
311 */
312 public void startElement (String name,
313 AttributeList atts)
314 throws SAXException {
315
316 if (abandonHope) {
317 return;
318 }
319
320 if (saxParser == null) {
321 String prefix = "";
322 if (name.indexOf(':') > 0) {
323 prefix = name.substring(0, name.indexOf(':'));
324 }
325
326 String localName = name;
327 if (localName.indexOf(':') > 0) {
328 localName = localName.substring(localName.indexOf(':')+1);
329 }
330
331 String namespaceURI = null;
332 if (prefix.equals("")) {
333 namespaceURI = atts.getValue("xmlns");
334 } else {
335 namespaceURI = atts.getValue("xmlns:" + prefix);
336 }
337
338 String saxParserClass = getCatalogParser(namespaceURI,
339 localName);
340
341 if (saxParserClass == null) {
342 abandonHope = true;
343 if (namespaceURI == null) {
344 debug.message(2, "No Catalog parser for " + name);
345 } else {
346 debug.message(2, "No Catalog parser for "
347 + "{" + namespaceURI + "}"
348 + name);
349 }
350 return;
351 }
352
353 try {
354 saxParser = (SAXCatalogParser)
355 Class.forName(saxParserClass).newInstance();
356
357 saxParser.setCatalog(catalog);
358 saxParser.startDocument();
359 saxParser.startElement(name, atts);
360 } catch (ClassNotFoundException cnfe) {
361 saxParser = null;
362 abandonHope = true;
363 debug.message(2, cnfe.toString());
364 } catch (InstantiationException ie) {
365 saxParser = null;
366 abandonHope = true;
367 debug.message(2, ie.toString());
368 } catch (IllegalAccessException iae) {
369 saxParser = null;
370 abandonHope = true;
371 debug.message(2, iae.toString());
372 } catch (ClassCastException cce ) {
373 saxParser = null;
374 abandonHope = true;
375 debug.message(2, cce.toString());
376 }
377 } else {
378 saxParser.startElement(name, atts);
379 }
380 }
381
382 /**
383 * The SAX2 <code>startElement</code> method.
384 *
385 * <p>The catalog parser is selected based on the namespace of the
386 * first element encountered in the catalog.</p>
387 */
388 public void startElement (String namespaceURI,
389 String localName,
390 String qName,
391 Attributes atts)
392 throws SAXException {
393
394 if (abandonHope) {
395 return;
396 }
397
398 if (saxParser == null) {
399 String saxParserClass = getCatalogParser(namespaceURI,
400 localName);
401
402 if (saxParserClass == null) {
403 abandonHope = true;
404 if (namespaceURI == null) {
405 debug.message(2, "No Catalog parser for " + localName);
406 } else {
407 debug.message(2, "No Catalog parser for "
408 + "{" + namespaceURI + "}"
409 + localName);
410 }
411 return;
412 }
413
414 try {
415 saxParser = (SAXCatalogParser)
416 Class.forName(saxParserClass).newInstance();
417
418 saxParser.setCatalog(catalog);
419 saxParser.startDocument();
420 saxParser.startElement(namespaceURI, localName, qName, atts);
421 } catch (ClassNotFoundException cnfe) {
422 saxParser = null;
423 abandonHope = true;
424 debug.message(2, cnfe.toString());
425 } catch (InstantiationException ie) {
426 saxParser = null;
427 abandonHope = true;
428 debug.message(2, ie.toString());
429 } catch (IllegalAccessException iae) {
430 saxParser = null;
431 abandonHope = true;
432 debug.message(2, iae.toString());
433 } catch (ClassCastException cce ) {
434 saxParser = null;
435 abandonHope = true;
436 debug.message(2, cce.toString());
437 }
438 } else {
439 saxParser.startElement(namespaceURI, localName, qName, atts);
440 }
441 }
442
443 /** The SAX <code>endElement</code> method. Does nothing. */
444 public void endElement (String name) throws SAXException {
445 if (saxParser != null) {
446 saxParser.endElement(name);
447 }
448 }
449
450 /** The SAX2 <code>endElement</code> method. Does nothing. */
451 public void endElement (String namespaceURI,
452 String localName,
453 String qName) throws SAXException {
454 if (saxParser != null) {
455 saxParser.endElement(namespaceURI, localName, qName);
456 }
457 }
458
459 /** The SAX <code>characters</code> method. Does nothing. */
460 public void characters (char ch[], int start, int length)
461 throws SAXException {
462 if (saxParser != null) {
463 saxParser.characters(ch, start, length);
464 }
465 }
466
467 /** The SAX <code>ignorableWhitespace</code> method. Does nothing. */
468 public void ignorableWhitespace (char ch[], int start, int length)
469 throws SAXException {
470 if (saxParser != null) {
471 saxParser.ignorableWhitespace(ch, start, length);
472 }
473 }
474
475 /** The SAX <code>processingInstruction</code> method. Does nothing. */
476 public void processingInstruction (String target, String data)
477 throws SAXException {
478 if (saxParser != null) {
479 saxParser.processingInstruction(target, data);
480 }
481 }
482
483 /** The SAX <code>startPrefixMapping</code> method. Does nothing. */
484 public void startPrefixMapping (String prefix, String uri)
485 throws SAXException {
486 if (saxParser != null) {
487 saxParser.startPrefixMapping (prefix, uri);
488 }
489 }
490
491 /** The SAX <code>endPrefixMapping</code> method. Does nothing. */
492 public void endPrefixMapping (String prefix)
493 throws SAXException {
494 if (saxParser != null) {
495 saxParser.endPrefixMapping (prefix);
496 }
497 }
498
499 /** The SAX <code>skippedentity</code> method. Does nothing. */
500 public void skippedEntity (String name)
501 throws SAXException {
502 if (saxParser != null) {
503 saxParser.skippedEntity(name);
504 }
505 }
506 }