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Java > Open Source Codes > org > xml > sax > helpers > XMLReaderAdapter


1 // XMLReaderAdapter.java - adapt an SAX2 XMLReader to a SAX1 Parser
2 // http://www.saxproject.org
3 // Written by David Megginson
4 // NO WARRANTY! This class is in the public domain.
5 // $Id: XMLReaderAdapter.java,v 1.2.22.1 2004/05/01 08:34:46 jsuttor Exp $
6
7 package org.xml.sax.helpers;
8
9 import java.io.IOException JavaDoc;
10 import java.util.Locale JavaDoc;
11
12 import org.xml.sax.Parser JavaDoc; // deprecated
13 import org.xml.sax.Locator JavaDoc;
14 import org.xml.sax.InputSource JavaDoc;
15 import org.xml.sax.AttributeList JavaDoc; // deprecated
16 import org.xml.sax.EntityResolver JavaDoc;
17 import org.xml.sax.DTDHandler JavaDoc;
18 import org.xml.sax.DocumentHandler JavaDoc; // deprecated
19 import org.xml.sax.ErrorHandler JavaDoc;
20 import org.xml.sax.SAXException JavaDoc;
21
22 import org.xml.sax.XMLReader JavaDoc;
23 import org.xml.sax.Attributes JavaDoc;
24 import org.xml.sax.ContentHandler JavaDoc;
25 import org.xml.sax.SAXNotSupportedException JavaDoc;
26
27
28 /**
29  * Adapt a SAX2 XMLReader as a SAX1 Parser.
30  *
31  * <blockquote>
32  * <em>This module, both source code and documentation, is in the
33  * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
34  * See <a HREF='http://www.saxproject.org'>http://www.saxproject.org</a>
35  * for further information.
36  * </blockquote>
37  *
38  * <p>This class wraps a SAX2 {@link org.xml.sax.XMLReader XMLReader}
39  * and makes it act as a SAX1 {@link org.xml.sax.Parser Parser}. The XMLReader
40  * must support a true value for the
41  * http://xml.org/sax/features/namespace-prefixes property or parsing will fail
42  * with a {@link org.xml.sax.SAXException SAXException}; if the XMLReader
43  * supports a false value for the http://xml.org/sax/features/namespaces
44  * property, that will also be used to improve efficiency.</p>
45  *
46  * @since SAX 2.0
47  * @author David Megginson
48  * @version 2.0.1 (sax2r2)
49  * @see org.xml.sax.Parser
50  * @see org.xml.sax.XMLReader
51  */
52 public class XMLReaderAdapter implements Parser JavaDoc, ContentHandler JavaDoc
53 {
54
55
56     ////////////////////////////////////////////////////////////////////
57 // Constructor.
58 ////////////////////////////////////////////////////////////////////
59
60
61     /**
62      * Create a new adapter.
63      *
64      * <p>Use the "org.xml.sax.driver" property to locate the SAX2
65      * driver to embed.</p>
66      *
67      * @exception org.xml.sax.SAXException If the embedded driver
68      * cannot be instantiated or if the
69      * org.xml.sax.driver property is not specified.
70      */
71     public XMLReaderAdapter ()
72       throws SAXException JavaDoc
73     {
74     setup(XMLReaderFactory.createXMLReader());
75     }
76
77
78     /**
79      * Create a new adapter.
80      *
81      * <p>Create a new adapter, wrapped around a SAX2 XMLReader.
82      * The adapter will make the XMLReader act like a SAX1
83      * Parser.</p>
84      *
85      * @param xmlReader The SAX2 XMLReader to wrap.
86      * @exception java.lang.NullPointerException If the argument is null.
87      */
88     public XMLReaderAdapter (XMLReader JavaDoc xmlReader)
89     {
90     setup(xmlReader);
91     }
92
93
94
95     /**
96      * Internal setup.
97      *
98      * @param xmlReader The embedded XMLReader.
99      */
100     private void setup (XMLReader JavaDoc xmlReader)
101     {
102     if (xmlReader == null) {
103         throw new NullPointerException JavaDoc("XMLReader must not be null");
104     }
105     this.xmlReader = xmlReader;
106     qAtts = new AttributesAdapter();
107     }
108
109
110
111     ////////////////////////////////////////////////////////////////////
112 // Implementation of org.xml.sax.Parser.
113 ////////////////////////////////////////////////////////////////////
114
115
116     /**
117      * Set the locale for error reporting.
118      *
119      * <p>This is not supported in SAX2, and will always throw
120      * an exception.</p>
121      *
122      * @param locale the locale for error reporting.
123      * @see org.xml.sax.Parser#setLocale
124      * @exception org.xml.sax.SAXException Thrown unless overridden.
125      */
126     public void setLocale (Locale JavaDoc locale)
127     throws SAXException JavaDoc
128     {
129     throw new SAXNotSupportedException JavaDoc("setLocale not supported");
130     }
131
132
133     /**
134      * Register the entity resolver.
135      *
136      * @param resolver The new resolver.
137      * @see org.xml.sax.Parser#setEntityResolver
138      */
139     public void setEntityResolver (EntityResolver JavaDoc resolver)
140     {
141     xmlReader.setEntityResolver(resolver);
142     }
143
144
145     /**
146      * Register the DTD event handler.
147      *
148      * @param handler The new DTD event handler.
149      * @see org.xml.sax.Parser#setDTDHandler
150      */
151     public void setDTDHandler (DTDHandler JavaDoc handler)
152     {
153     xmlReader.setDTDHandler(handler);
154     }
155
156
157     /**
158      * Register the SAX1 document event handler.
159      *
160      * <p>Note that the SAX1 document handler has no Namespace
161      * support.</p>
162      *
163      * @param handler The new SAX1 document event handler.
164      * @see org.xml.sax.Parser#setDocumentHandler
165      */
166     public void setDocumentHandler (DocumentHandler JavaDoc handler)
167     {
168     documentHandler = handler;
169     }
170
171
172     /**
173      * Register the error event handler.
174      *
175      * @param handler The new error event handler.
176      * @see org.xml.sax.Parser#setErrorHandler
177      */
178     public void setErrorHandler (ErrorHandler JavaDoc handler)
179     {
180     xmlReader.setErrorHandler(handler);
181     }
182
183
184     /**
185      * Parse the document.
186      *
187      * <p>This method will throw an exception if the embedded
188      * XMLReader does not support the
189      * http://xml.org/sax/features/namespace-prefixes property.</p>
190      *
191      * @param systemId The absolute URL of the document.
192      * @exception java.io.IOException If there is a problem reading
193      * the raw content of the document.
194      * @exception org.xml.sax.SAXException If there is a problem
195      * processing the document.
196      * @see #parse(org.xml.sax.InputSource)
197      * @see org.xml.sax.Parser#parse(java.lang.String)
198      */
199     public void parse (String JavaDoc systemId)
200     throws IOException JavaDoc, SAXException JavaDoc
201     {
202     parse(new InputSource JavaDoc(systemId));
203     }
204
205
206     /**
207      * Parse the document.
208      *
209      * <p>This method will throw an exception if the embedded
210      * XMLReader does not support the
211      * http://xml.org/sax/features/namespace-prefixes property.</p>
212      *
213      * @param input An input source for the document.
214      * @exception java.io.IOException If there is a problem reading
215      * the raw content of the document.
216      * @exception org.xml.sax.SAXException If there is a problem
217      * processing the document.
218      * @see #parse(java.lang.String)
219      * @see org.xml.sax.Parser#parse(org.xml.sax.InputSource)
220      */
221     public void parse (InputSource JavaDoc input)
222     throws IOException JavaDoc, SAXException JavaDoc
223     {
224     setupXMLReader();
225     xmlReader.parse(input);
226     }
227
228
229     /**
230      * Set up the XML reader.
231      */
232     private void setupXMLReader ()
233     throws SAXException JavaDoc
234     {
235     xmlReader.setFeature("http://xml.org/sax/features/namespace-prefixes", true);
236     try {
237         xmlReader.setFeature("http://xml.org/sax/features/namespaces",
238                              false);
239     } catch (SAXException JavaDoc e) {
240         // NO OP: it's just extra information, and we can ignore it
241 }
242     xmlReader.setContentHandler(this);
243     }
244
245
246
247     ////////////////////////////////////////////////////////////////////
248 // Implementation of org.xml.sax.ContentHandler.
249 ////////////////////////////////////////////////////////////////////
250
251
252     /**
253      * Set a document locator.
254      *
255      * @param locator The document locator.
256      * @see org.xml.sax.ContentHandler#setDocumentLocator
257      */
258     public void setDocumentLocator (Locator JavaDoc locator)
259     {
260     if (documentHandler != null)
261         documentHandler.setDocumentLocator(locator);
262     }
263
264
265     /**
266      * Start document event.
267      *
268      * @exception org.xml.sax.SAXException The client may raise a
269      * processing exception.
270      * @see org.xml.sax.ContentHandler#startDocument
271      */
272     public void startDocument ()
273     throws SAXException JavaDoc
274     {
275     if (documentHandler != null)
276         documentHandler.startDocument();
277     }
278
279
280     /**
281      * End document event.
282      *
283      * @exception org.xml.sax.SAXException The client may raise a
284      * processing exception.
285      * @see org.xml.sax.ContentHandler#endDocument
286      */
287     public void endDocument ()
288     throws SAXException JavaDoc
289     {
290     if (documentHandler != null)
291         documentHandler.endDocument();
292     }
293
294
295     /**
296      * Adapt a SAX2 start prefix mapping event.
297      *
298      * @param prefix The prefix being mapped.
299      * @param uri The Namespace URI being mapped to.
300      * @see org.xml.sax.ContentHandler#startPrefixMapping
301      */
302     public void startPrefixMapping (String JavaDoc prefix, String JavaDoc uri)
303     {
304     }
305
306
307     /**
308      * Adapt a SAX2 end prefix mapping event.
309      *
310      * @param prefix The prefix being mapped.
311      * @see org.xml.sax.ContentHandler#endPrefixMapping
312      */
313     public void endPrefixMapping (String JavaDoc prefix)
314     {
315     }
316
317
318     /**
319      * Adapt a SAX2 start element event.
320      *
321      * @param uri The Namespace URI.
322      * @param localName The Namespace local name.
323      * @param qName The qualified (prefixed) name.
324      * @param atts The SAX2 attributes.
325      * @exception org.xml.sax.SAXException The client may raise a
326      * processing exception.
327      * @see org.xml.sax.ContentHandler#endDocument
328      */
329     public void startElement (String JavaDoc uri, String JavaDoc localName,
330                   String JavaDoc qName, Attributes JavaDoc atts)
331     throws SAXException JavaDoc
332     {
333     if (documentHandler != null) {
334         qAtts.setAttributes(atts);
335         documentHandler.startElement(qName, qAtts);
336     }
337     }
338
339
340     /**
341      * Adapt a SAX2 end element event.
342      *
343      * @param uri The Namespace URI.
344      * @param localName The Namespace local name.
345      * @param qName The qualified (prefixed) name.
346      * @exception org.xml.sax.SAXException The client may raise a
347      * processing exception.
348      * @see org.xml.sax.ContentHandler#endElement
349      */
350     public void endElement (String JavaDoc uri, String JavaDoc localName,
351                 String JavaDoc qName)
352     throws SAXException JavaDoc
353     {
354     if (documentHandler != null)
355         documentHandler.endElement(qName);
356     }
357
358
359     /**
360      * Adapt a SAX2 characters event.
361      *
362      * @param ch An array of characters.
363      * @param start The starting position in the array.
364      * @param length The number of characters to use.
365      * @exception org.xml.sax.SAXException The client may raise a
366      * processing exception.
367      * @see org.xml.sax.ContentHandler#characters
368      */
369     public void characters (char ch[], int start, int length)
370     throws SAXException JavaDoc
371     {
372     if (documentHandler != null)
373         documentHandler.characters(ch, start, length);
374     }
375
376
377     /**
378      * Adapt a SAX2 ignorable whitespace event.
379      *
380      * @param ch An array of characters.
381      * @param start The starting position in the array.
382      * @param length The number of characters to use.
383      * @exception org.xml.sax.SAXException The client may raise a
384      * processing exception.
385      * @see org.xml.sax.ContentHandler#ignorableWhitespace
386      */
387     public void ignorableWhitespace (char ch[], int start, int length)
388     throws SAXException JavaDoc
389     {
390     if (documentHandler != null)
391         documentHandler.ignorableWhitespace(ch, start, length);
392     }
393
394
395     /**
396      * Adapt a SAX2 processing instruction event.
397      *
398      * @param target The processing instruction target.
399      * @param data The remainder of the processing instruction
400      * @exception org.xml.sax.SAXException The client may raise a
401      * processing exception.
402      * @see org.xml.sax.ContentHandler#processingInstruction
403      */
404     public void processingInstruction (String JavaDoc target, String JavaDoc data)
405     throws SAXException JavaDoc
406     {
407     if (documentHandler != null)
408         documentHandler.processingInstruction(target, data);
409     }
410
411
412     /**
413      * Adapt a SAX2 skipped entity event.
414      *
415      * @param name The name of the skipped entity.
416      * @see org.xml.sax.ContentHandler#skippedEntity
417      * @exception org.xml.sax.SAXException Throwable by subclasses.
418      */
419     public void skippedEntity (String JavaDoc name)
420     throws SAXException JavaDoc
421     {
422     }
423
424
425
426     ////////////////////////////////////////////////////////////////////
427 // Internal state.
428 ////////////////////////////////////////////////////////////////////
429
430     XMLReader JavaDoc xmlReader;
431     DocumentHandler JavaDoc documentHandler;
432     AttributesAdapter qAtts;
433
434
435
436     ////////////////////////////////////////////////////////////////////
437 // Internal class.
438 ////////////////////////////////////////////////////////////////////
439
440
441     /**
442      * Internal class to wrap a SAX2 Attributes object for SAX1.
443      */
444     final class AttributesAdapter implements AttributeList JavaDoc
445     {
446     AttributesAdapter ()
447     {
448     }
449
450
451     /**
452      * Set the embedded Attributes object.
453      *
454      * @param The embedded SAX2 Attributes.
455      */
456     void setAttributes (Attributes JavaDoc attributes)
457     {
458         this.attributes = attributes;
459     }
460
461
462     /**
463      * Return the number of attributes.
464      *
465      * @return The length of the attribute list.
466      * @see org.xml.sax.AttributeList#getLength
467      */
468     public int getLength ()
469     {
470         return attributes.getLength();
471     }
472
473
474     /**
475      * Return the qualified (prefixed) name of an attribute by position.
476      *
477      * @return The qualified name.
478      * @see org.xml.sax.AttributeList#getName
479      */
480     public String JavaDoc getName (int i)
481     {
482         return attributes.getQName(i);
483     }
484
485
486     /**
487      * Return the type of an attribute by position.
488      *
489      * @return The type.
490      * @see org.xml.sax.AttributeList#getType(int)
491      */
492     public String JavaDoc getType (int i)
493     {
494         return attributes.getType(i);
495     }
496
497
498     /**
499      * Return the value of an attribute by position.
500      *
501      * @return The value.
502      * @see org.xml.sax.AttributeList#getValue(int)
503      */
504     public String JavaDoc getValue (int i)
505     {
506         return attributes.getValue(i);
507     }
508
509
510     /**
511      * Return the type of an attribute by qualified (prefixed) name.
512      *
513      * @return The type.
514      * @see org.xml.sax.AttributeList#getType(java.lang.String)
515      */
516     public String JavaDoc getType (String JavaDoc qName)
517     {
518         return attributes.getType(qName);
519     }
520
521
522     /**
523      * Return the value of an attribute by qualified (prefixed) name.
524      *
525      * @return The value.
526      * @see org.xml.sax.AttributeList#getValue(java.lang.String)
527      */
528     public String JavaDoc getValue (String JavaDoc qName)
529     {
530         return attributes.getValue(qName);
531     }
532
533     private Attributes JavaDoc attributes;
534     }
535
536 }
537
538 // end of XMLReaderAdapter.java
539
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