1 /*
2 * Copyright 2006 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.oxm;
18
19 import java.io.IOException;
20 import java.io.InputStream;
21 import java.io.OutputStream;
22 import java.io.Reader;
23 import java.io.Writer;
24 import javax.xml.parsers.DocumentBuilder;
25 import javax.xml.parsers.DocumentBuilderFactory;
26 import javax.xml.parsers.ParserConfigurationException;
27 import javax.xml.stream.XMLEventReader;
28 import javax.xml.stream.XMLEventWriter;
29 import javax.xml.stream.XMLStreamReader;
30 import javax.xml.stream.XMLStreamWriter;
31 import javax.xml.transform.Result;
32 import javax.xml.transform.Source;
33 import javax.xml.transform.dom.DOMResult;
34 import javax.xml.transform.dom.DOMSource;
35 import javax.xml.transform.sax.SAXResult;
36 import javax.xml.transform.sax.SAXSource;
37 import javax.xml.transform.stream.StreamResult;
38 import javax.xml.transform.stream.StreamSource;
39
40 import org.apache.commons.logging.Log;
41 import org.apache.commons.logging.LogFactory;
42 import org.springframework.util.Assert;
43 import org.springframework.xml.transform.StaxResult;
44 import org.springframework.xml.transform.StaxSource;
45 import org.w3c.dom.Node;
46 import org.xml.sax.ContentHandler;
47 import org.xml.sax.InputSource;
48 import org.xml.sax.SAXException;
49 import org.xml.sax.XMLReader;
50 import org.xml.sax.ext.LexicalHandler;
51 import org.xml.sax.helpers.XMLReaderFactory;
52
53 /**
54 * Abstract implementation of the <code>Marshaller</code> and <code>Unmarshaller</code> interface. This implementation
55 * inspects the given <code>Source</code> or <code>Result</code>, and defers further handling to overridable template
56 * methods.
57 *
58 * @author Arjen Poutsma
59 * @since 1.0.0
60 */
61 public abstract class AbstractMarshaller implements Marshaller, Unmarshaller {
62
63 /**
64 * Logger available to subclasses.
65 */
66 protected final Log logger = LogFactory.getLog(getClass());
67
68 private DocumentBuilderFactory documentBuilderFactory;
69
70 /**
71 * Marshals the object graph with the given root into the provided <code>javax.xml.transform.Result</code>.
72 * <p/>
73 * This implementation inspects the given result, and calls <code>marshalDomResult</code>,
74 * <code>marshalSaxResult</code>, or <code>marshalStreamResult</code>.
75 *
76 * @param graph the root of the object graph to marshal
77 * @param result the result to marshal to
78 * @throws XmlMappingException if the given object cannot be marshalled to the result
79 * @throws IOException if an I/O exception occurs
80 * @throws IllegalArgumentException if <code>result</code> if neither a <code>DOMResult</code>,
81 * <code>SAXResult</code>, <code>StreamResult</code>
82 * @see #marshalDomResult(Object,javax.xml.transform.dom.DOMResult)
83 * @see #marshalSaxResult(Object,javax.xml.transform.sax.SAXResult)
84 * @see #marshalStreamResult(Object,javax.xml.transform.stream.StreamResult)
85 */
86 public final void marshal(Object graph, Result result) throws XmlMappingException, IOException {
87 if (result instanceof DOMResult) {
88 marshalDomResult(graph, (DOMResult) result);
89 }
90 else if (result instanceof StaxResult) {
91 marshalStaxResult(graph, (StaxResult) result);
92 }
93 else if (result instanceof SAXResult) {
94 marshalSaxResult(graph, (SAXResult) result);
95 }
96 else if (result instanceof StreamResult) {
97 marshalStreamResult(graph, (StreamResult) result);
98 }
99 else {
100 throw new IllegalArgumentException("Unknown Result type: " + result.getClass());
101 }
102 }
103
104 /**
105 * Unmarshals the given provided <code>javax.xml.transform.Source</code> into an object graph.
106 * <p/>
107 * This implementation inspects the given result, and calls <code>unmarshalDomSource</code>,
108 * <code>unmarshalSaxSource</code>, or <code>unmarshalStreamSource</code>.
109 *
110 * @param source the source to marshal from
111 * @return the object graph
112 * @throws XmlMappingException if the given source cannot be mapped to an object
113 * @throws IOException if an I/O Exception occurs
114 * @throws IllegalArgumentException if <code>source</code> is neither a <code>DOMSource</code>, a
115 * <code>SAXSource</code>, nor a <code>StreamSource</code>
116 * @see #unmarshalDomSource(javax.xml.transform.dom.DOMSource)
117 * @see #unmarshalSaxSource(javax.xml.transform.sax.SAXSource)
118 * @see #unmarshalStreamSource(javax.xml.transform.stream.StreamSource)
119 */
120 public final Object unmarshal(Source source) throws XmlMappingException, IOException {
121 if (source instanceof DOMSource) {
122 return unmarshalDomSource((DOMSource) source);
123 }
124 else if (source instanceof StaxSource) {
125 return unmarshalStaxSource((StaxSource) source);
126 }
127 else if (source instanceof SAXSource) {
128 return unmarshalSaxSource((SAXSource) source);
129 }
130 else if (source instanceof StreamSource) {
131 return unmarshalStreamSource((StreamSource) source);
132 }
133 else {
134 throw new IllegalArgumentException("Unknown Source type: " + source.getClass());
135 }
136 }
137
138 /**
139 * Create a <code>DocumentBuilder</code> that this marshaller will use for creating DOM documents when passed an
140 * empty <code>DOMSource</code>. Can be overridden in subclasses, adding further initialization of the builder.
141 *
142 * @param factory the <code>DocumentBuilderFactory</code> that the DocumentBuilder should be created with
143 * @return the <code>DocumentBuilder</code>
144 * @throws javax.xml.parsers.ParserConfigurationException
145 * if thrown by JAXP methods
146 */
147 protected DocumentBuilder createDocumentBuilder(DocumentBuilderFactory factory)
148 throws ParserConfigurationException {
149 return factory.newDocumentBuilder();
150 }
151
152 /**
153 * Create a <code>DocumentBuilder</code> that this marshaller will use for creating DOM documents when passed an
154 * empty <code>DOMSource</code>. The resulting <code>DocumentBuilderFactory</code> is cached, so this method will
155 * only be called once.
156 *
157 * @return the DocumentBuilderFactory
158 * @throws ParserConfigurationException if thrown by JAXP methods
159 */
160 protected DocumentBuilderFactory createDocumentBuilderFactory() throws ParserConfigurationException {
161 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
162 factory.setValidating(false);
163 factory.setNamespaceAware(true);
164 return factory;
165 }
166
167 /**
168 * Create a <code>XMLReader</code> that this marshaller will when passed an empty <code>SAXSource</code>.
169 *
170 * @return the XMLReader
171 * @throws SAXException if thrown by JAXP methods
172 */
173 protected XMLReader createXmlReader() throws SAXException {
174 return XMLReaderFactory.createXMLReader();
175 }
176
177 //
178 // Marshalling
179 //
180
181 /**
182 * Template method for handling <code>DOMResult</code>s. This implementation defers to <code>marshalDomNode</code>.
183 *
184 * @param graph the root of the object graph to marshal
185 * @param domResult the <code>DOMResult</code>
186 * @throws XmlMappingException if the given object cannot be marshalled to the result
187 * @throws IllegalArgumentException if the <code>domResult</code> is empty
188 * @see #marshalDomNode(Object,org.w3c.dom.Node)
189 */
190 protected void marshalDomResult(Object graph, DOMResult domResult) throws XmlMappingException {
191 Assert.notNull(domResult.getNode(), "DOMResult does not contain Node");
192 marshalDomNode(graph, domResult.getNode());
193 }
194
195 /**
196 * Template method for handling <code>StaxResult</code>s. This implementation defers to
197 * <code>marshalXMLSteamWriter</code>, or <code>marshalXMLEventConsumer</code>, depending on what is contained in
198 * the <code>StaxResult</code>.
199 *
200 * @param graph the root of the object graph to marshal
201 * @param staxResult the <code>StaxResult</code>
202 * @throws XmlMappingException if the given object cannot be marshalled to the result
203 * @throws IllegalArgumentException if the <code>domResult</code> is empty
204 * @see #marshalDomNode(Object,org.w3c.dom.Node)
205 */
206 protected void marshalStaxResult(Object graph, StaxResult staxResult) throws XmlMappingException {
207 if (staxResult.getXMLStreamWriter() != null) {
208 marshalXmlStreamWriter(graph, staxResult.getXMLStreamWriter());
209 }
210 else if (staxResult.getXMLEventWriter() != null) {
211 marshalXmlEventWriter(graph, staxResult.getXMLEventWriter());
212 }
213 else {
214 throw new IllegalArgumentException("StaxResult contains neither XMLStreamWriter nor XMLEventConsumer");
215 }
216 }
217
218 /**
219 * Template method for handling <code>SAXResult</code>s. This implementation defers to
220 * <code>marshalSaxHandlers</code>.
221 *
222 * @param graph the root of the object graph to marshal
223 * @param saxResult the <code>SAXResult</code>
224 * @throws XmlMappingException if the given object cannot be marshalled to the result
225 * @see #marshalSaxHandlers(Object,org.xml.sax.ContentHandler,org.xml.sax.ext.LexicalHandler)
226 */
227 protected void marshalSaxResult(Object graph, SAXResult saxResult) throws XmlMappingException {
228 ContentHandler contentHandler = saxResult.getHandler();
229 Assert.notNull(contentHandler, "ContentHandler not set on SAXResult");
230 LexicalHandler lexicalHandler = saxResult.getLexicalHandler();
231 marshalSaxHandlers(graph, contentHandler, lexicalHandler);
232 }
233
234 /**
235 * Template method for handling <code>StreamResult</code>s. This implementation defers to
236 * <code>marshalOutputStream</code>, or <code>marshalWriter</code>, depending on what is contained in the
237 * <code>StreamResult</code>
238 *
239 * @param graph the root of the object graph to marshal
240 * @param streamResult the <code>StreamResult</code>
241 * @throws IOException if an I/O Exception occurs
242 * @throws XmlMappingException if the given object cannot be marshalled to the result
243 * @throws IllegalArgumentException if <code>streamResult</code> contains neither <code>OutputStream</code> nor
244 * <code>Writer</code>.
245 */
246 protected void marshalStreamResult(Object graph, StreamResult streamResult)
247 throws XmlMappingException, IOException {
248 if (streamResult.getOutputStream() != null) {
249 marshalOutputStream(graph, streamResult.getOutputStream());
250 }
251 else if (streamResult.getWriter() != null) {
252 marshalWriter(graph, streamResult.getWriter());
253 }
254 else {
255 throw new IllegalArgumentException("StreamResult contains neither OutputStream nor Writer");
256 }
257 }
258
259 //
260 // Unmarshalling
261 //
262
263 /**
264 * Template method for handling <code>DOMSource</code>s. This implementation defers to
265 * <code>unmarshalDomNode</code>. If the given source is empty, an empty source <code>Document</code> will be
266 * created as a placeholder.
267 *
268 * @param domSource the <code>DOMSource</code>
269 * @return the object graph
270 * @throws IllegalArgumentException if the <code>domSource</code> is empty
271 * @throws XmlMappingException if the given source cannot be mapped to an object
272 * @see #unmarshalDomNode(org.w3c.dom.Node)
273 */
274 protected Object unmarshalDomSource(DOMSource domSource) throws XmlMappingException {
275 if (domSource.getNode() == null) {
276 try {
277 if (documentBuilderFactory == null) {
278 documentBuilderFactory = createDocumentBuilderFactory();
279 }
280 DocumentBuilder documentBuilder = createDocumentBuilder(documentBuilderFactory);
281 domSource.setNode(documentBuilder.newDocument());
282 }
283 catch (ParserConfigurationException ex) {
284 throw new UnmarshallingFailureException(
285 "Could not create document placeholder for DOMSource: " + ex.getMessage(), ex);
286 }
287 }
288 return unmarshalDomNode(domSource.getNode());
289 }
290
291 /**
292 * Template method for handling <code>StaxSource</code>s. This implementation defers to
293 * <code>unmarshalXmlStreamReader</code>, or <code>unmarshalXmlEventReader</code>.
294 *
295 * @param staxSource the <code>StaxSource</code>
296 * @return the object graph
297 * @throws XmlMappingException if the given source cannot be mapped to an object
298 */
299 protected Object unmarshalStaxSource(StaxSource staxSource) throws XmlMappingException {
300 if (staxSource.getXMLStreamReader() != null) {
301 return unmarshalXmlStreamReader(staxSource.getXMLStreamReader());
302 }
303 else if (staxSource.getXMLEventReader() != null) {
304 return unmarshalXmlEventReader(staxSource.getXMLEventReader());
305 }
306 else {
307 throw new IllegalArgumentException("StaxSource contains neither XMLStreamReader nor XMLEventReader");
308 }
309 }
310
311 /**
312 * Template method for handling <code>SAXSource</code>s. This implementation defers to
313 * <code>unmarshalSaxReader</code>.
314 *
315 * @param saxSource the <code>SAXSource</code>
316 * @return the object graph
317 * @throws XmlMappingException if the given source cannot be mapped to an object
318 * @throws IOException if an I/O Exception occurs
319 * @see #unmarshalSaxReader(org.xml.sax.XMLReader,org.xml.sax.InputSource)
320 */
321 protected Object unmarshalSaxSource(SAXSource saxSource) throws XmlMappingException, IOException {
322 if (saxSource.getXMLReader() == null) {
323 try {
324 saxSource.setXMLReader(createXmlReader());
325 }
326 catch (SAXException ex) {
327 throw new UnmarshallingFailureException("Could not create XMLReader for SAXSource: " + ex.getMessage(),
328 ex);
329 }
330 }
331 if (saxSource.getInputSource() == null) {
332 saxSource.setInputSource(new InputSource());
333 }
334 return unmarshalSaxReader(saxSource.getXMLReader(), saxSource.getInputSource());
335 }
336
337 /**
338 * Template method for handling <code>StreamSource</code>s. This implementation defers to
339 * <code>unmarshalInputStream</code>, or <code>unmarshalReader</code>.
340 *
341 * @param streamSource the <code>StreamSource</code>
342 * @return the object graph
343 * @throws IOException if an I/O exception occurs
344 * @throws XmlMappingException if the given source cannot be mapped to an object
345 */
346 protected Object unmarshalStreamSource(StreamSource streamSource) throws XmlMappingException, IOException {
347 if (streamSource.getInputStream() != null) {
348 return unmarshalInputStream(streamSource.getInputStream());
349 }
350 else if (streamSource.getReader() != null) {
351 return unmarshalReader(streamSource.getReader());
352 }
353 else {
354 throw new IllegalArgumentException("StreamSource contains neither InputStream nor Reader");
355 }
356 }
357
358 //
359 // Abstract template methods
360 //
361
362 /**
363 * Abstract template method for marshalling the given object graph to a DOM <code>Node</code>.
364 * <p/>
365 * In practice, node is be a <code>Document</code> node, a <code>DocumentFragment</code> node, or a
366 * <code>Element</code> node. In other words, a node that accepts children.
367 *
368 * @param graph the root of the object graph to marshal
369 * @param node The DOM node that will contain the result tree
370 * @throws XmlMappingException if the given object cannot be marshalled to the DOM node
371 * @see org.w3c.dom.Document
372 * @see org.w3c.dom.DocumentFragment
373 * @see org.w3c.dom.Element
374 */
375 protected abstract void marshalDomNode(Object graph, Node node) throws XmlMappingException;
376
377 /**
378 * Abstract template method for marshalling the given object to a StAX <code>XMLEventWriter</code>.
379 *
380 * @param graph the root of the object graph to marshal
381 * @param eventWriter the <code>XMLEventWriter</code> to write to
382 * @throws XmlMappingException if the given object cannot be marshalled to the DOM node
383 */
384 protected abstract void marshalXmlEventWriter(Object graph, XMLEventWriter eventWriter) throws XmlMappingException;
385
386 /**
387 * Abstract template method for marshalling the given object to a StAX <code>XMLStreamWriter</code>.
388 *
389 * @param graph the root of the object graph to marshal
390 * @param streamWriter the <code>XMLStreamWriter</code> to write to
391 * @throws XmlMappingException if the given object cannot be marshalled to the DOM node
392 */
393 protected abstract void marshalXmlStreamWriter(Object graph, XMLStreamWriter streamWriter)
394 throws XmlMappingException;
395
396 /**
397 * Abstract template method for marshalling the given object graph to a <code>OutputStream</code>.
398 *
399 * @param graph the root of the object graph to marshal
400 * @param outputStream the <code>OutputStream</code> to write to
401 * @throws XmlMappingException if the given object cannot be marshalled to the writer
402 * @throws IOException if an I/O exception occurs
403 */
404 protected abstract void marshalOutputStream(Object graph, OutputStream outputStream)
405 throws XmlMappingException, IOException;
406
407 /**
408 * Abstract template method for marshalling the given object graph to a SAX <code>ContentHandler</code>.
409 *
410 * @param graph the root of the object graph to marshal
411 * @param contentHandler the SAX <code>ContentHandler</code>
412 * @param lexicalHandler the SAX2 <code>LexicalHandler</code>. Can be <code>null</code>.
413 * @throws XmlMappingException if the given object cannot be marshalled to the handlers
414 */
415 protected abstract void marshalSaxHandlers(Object graph,
416 ContentHandler contentHandler,
417 LexicalHandler lexicalHandler) throws XmlMappingException;
418
419 /**
420 * Abstract template method for marshalling the given object graph to a <code>Writer</code>.
421 *
422 * @param graph the root of the object graph to marshal
423 * @param writer the <code>Writer</code> to write to
424 * @throws XmlMappingException if the given object cannot be marshalled to the writer
425 * @throws IOException if an I/O exception occurs
426 */
427 protected abstract void marshalWriter(Object graph, Writer writer) throws XmlMappingException, IOException;
428
429 /**
430 * Abstract template method for unmarshalling from a given DOM <code>Node</code>.
431 *
432 * @param node The DOM node that contains the objects to be unmarshalled
433 * @return the object graph
434 * @throws XmlMappingException if the given DOM node cannot be mapped to an object
435 */
436 protected abstract Object unmarshalDomNode(Node node) throws XmlMappingException;
437
438 /**
439 * Abstract template method for unmarshalling from a given Stax <code>XMLEventReader</code>.
440 *
441 * @param eventReader The <code>XMLEventReader</code> to read from
442 * @return the object graph
443 * @throws XmlMappingException if the given event reader cannot be converted to an object
444 */
445 protected abstract Object unmarshalXmlEventReader(XMLEventReader eventReader) throws XmlMappingException;
446
447 /**
448 * Abstract template method for unmarshalling from a given Stax <code>XMLStreamReader</code>.
449 *
450 * @param streamReader The <code>XMLStreamReader</code> to read from
451 * @return the object graph
452 * @throws XmlMappingException if the given stream reader cannot be converted to an object
453 */
454 protected abstract Object unmarshalXmlStreamReader(XMLStreamReader streamReader) throws XmlMappingException;
455
456 /**
457 * Abstract template method for unmarshalling from a given <code>InputStream</code>.
458 *
459 * @param inputStream the <code>InputStreamStream</code> to read from
460 * @return the object graph
461 * @throws XmlMappingException if the given stream cannot be converted to an object
462 * @throws IOException if an I/O exception occurs
463 */
464 protected abstract Object unmarshalInputStream(InputStream inputStream) throws XmlMappingException, IOException;
465
466 /**
467 * Abstract template method for unmarshalling from a given <code>Reader</code>.
468 *
469 * @param reader the <code>Reader</code> to read from
470 * @return the object graph
471 * @throws XmlMappingException if the given reader cannot be converted to an object
472 * @throws IOException if an I/O exception occurs
473 */
474 protected abstract Object unmarshalReader(Reader reader) throws XmlMappingException, IOException;
475
476 /**
477 * Abstract template method for unmarshalling using a given SAX <code>XMLReader</code> and
478 * <code>InputSource</code>.
479 *
480 * @param xmlReader the SAX <code>XMLReader</code> to parse with
481 * @param inputSource the input source to parse from
482 * @return the object graph
483 * @throws XmlMappingException if the given reader and input source cannot be converted to an object
484 * @throws java.io.IOException if an I/O exception occurs
485 */
486 protected abstract Object unmarshalSaxReader(XMLReader xmlReader, InputSource inputSource)
487 throws XmlMappingException, IOException;
488 }