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1
16
17 package org.springframework.web.servlet.view.xslt;
18
19 import java.io.IOException  ;
20 import java.io.InputStream ;
21 import java.io.Reader ;
22 import java.util.Enumeration ;
23 import java.util.Iterator ;
24 import java.util.Map ;
25 import java.util.Properties ;
26
27 import javax.servlet.http.HttpServletRequest ;
28 import javax.servlet.http.HttpServletResponse ;
29 import javax.xml.transform.ErrorListener ;
30 import javax.xml.transform.OutputKeys ;
31 import javax.xml.transform.Result ;
32 import javax.xml.transform.Source ;
33 import javax.xml.transform.Templates ;
34 import javax.xml.transform.Transformer ;
35 import javax.xml.transform.TransformerConfigurationException ;
36 import javax.xml.transform.TransformerFactory ;
37 import javax.xml.transform.URIResolver ;
38 import javax.xml.transform.dom.DOMSource ;
39 import javax.xml.transform.stream.StreamResult ;
40 import javax.xml.transform.stream.StreamSource ;
41
42 import org.w3c.dom.Document ;
43 import org.w3c.dom.Node ;
44
45 import org.springframework.beans.BeansException;
46 import org.springframework.context.ApplicationContextException;
47 import org.springframework.core.io.Resource;
48 import org.springframework.util.Assert;
49 import org.springframework.util.CollectionUtils;
50 import org.springframework.util.ObjectUtils;
51 import org.springframework.util.xml.SimpleTransformErrorListener;
52 import org.springframework.web.servlet.view.AbstractUrlBasedView;
53
54
72 public class XsltView extends AbstractUrlBasedView {
73
74 private TransformerFactory transformerFactory = TransformerFactory.newInstance();
75
76 private ErrorListener errorListener = new SimpleTransformErrorListener(logger);
77
78 private URIResolver uriResolver;
79
80 private boolean cacheTemplates = true;
81
82 private Templates cachedTemplates;
83
84 private String sourceKey;
85
86 private Properties outputProperties;
87
88 private boolean indent = true;
89
90
91
96 public void setCacheTemplates(boolean cacheTemplates) {
97 this.cacheTemplates = cacheTemplates;
98 }
99
100
105 public void setUriResolver(URIResolver uriResolver) {
106 this.uriResolver = uriResolver;
107 }
108
109 public void setErrorListener(ErrorListener errorListener) {
110 Assert.notNull(errorListener, "'errorListener' cannot be null.");
111 this.errorListener = errorListener;
112 }
113
114 public void setSourceKey(String sourceKey) {
115 this.sourceKey = sourceKey;
116 }
117
118 public void setOutputProperties(Properties outputProperties) {
119 this.outputProperties = outputProperties;
120 }
121
122 public void setIndent(boolean indent) {
123 this.indent = indent;
124 }
125
126 protected final TransformerFactory getTransformerFactory() {
127 return this.transformerFactory;
128 }
129
130
131 protected void initApplicationContext() throws BeansException {
132 this.getTransformerFactory().setErrorListener(this.errorListener);
133
134 if (this.uriResolver != null) {
135 if (logger.isInfoEnabled()) {
136 logger.info("Using custom URIResolver '" + this.uriResolver
137 + "' in XSLT view with URL '" + getUrl() + "'");
138 }
139 this.getTransformerFactory().setURIResolver(this.uriResolver);
140 }
141
142 if (logger.isDebugEnabled()) {
143 logger.debug("URL in view is '" + getUrl() + "'");
144 }
145
146 if (this.cacheTemplates) {
147 this.cachedTemplates = loadTemplates();
148 }
149 }
150
151 protected void renderMergedOutputModel(Map model, HttpServletRequest request, HttpServletResponse response) throws Exception {
152 Templates templates = this.cachedTemplates;
153 if (templates == null) {
154 logger.warn("DEBUG SETTING: WILL IMPAIR PERFORMANCE: template will be refreshed");
155 templates = loadTemplates();
156 }
157
158 Transformer transformer = createTransformer(templates);
159 configureTransformer(model, response, transformer);
160 configureResponse(model, response, transformer);
161 Source source = null;
162 try {
163 source = locateSource(model);
164 if(source == null) {
165 throw new IllegalArgumentException ("Unable to locate Source object in model.");
166 }
167 transformer.transform(source, createResult(response));
168 }
169 finally {
170 if (source != null) {
171 closeSourceIfNecessary(source);
172 }
173 }
174 }
175
176
181 protected Result createResult(HttpServletResponse response) throws Exception {
182 return new StreamResult (response.getOutputStream());
183 }
184
185
190 protected Source locateSource(Map model) throws Exception {
191 if (this.sourceKey != null) {
192 return convertSource(model.get(this.sourceKey));
193 }
194
195 Object source = CollectionUtils.findValueOfType(model.values(), getSourceTypes());
196 return (source != null ? convertSource(source) : null);
197 }
198
199
204 protected Class [] getSourceTypes() {
205 return new Class []{Source .class, Document .class, Node .class, InputStream .class, Reader .class, Resource.class};
206 }
207
208
214 protected Source convertSource(Object source) throws Exception {
215 if (source instanceof Source ) {
216 return (Source ) source;
217 }
218 else if (source instanceof Document ) {
219 return new DOMSource (((Document ) source).getDocumentElement());
220 }
221 else if (source instanceof Node ) {
222 return new DOMSource ((Node ) source);
223 }
224 else if (source instanceof InputStream ) {
225 return new StreamSource ((InputStream ) source);
226 }
227 else if (source instanceof Reader ) {
228 return new StreamSource ((Reader ) source);
229 }
230 else if (source instanceof Resource) {
231 return new StreamSource (((Resource) source).getInputStream());
232 }
233 else {
234 throw new IllegalArgumentException ("Value '" + source + "' cannot be converted to Source.");
235 }
236 }
237
238
249 protected void configureTransformer(Map model, HttpServletResponse response, Transformer transformer) {
250 copyModelParameters(model, transformer);
251 copyOutputProperties(transformer);
252 configureIndentation(transformer);
253 }
254
255
262 protected final void configureIndentation(Transformer transformer) {
263 if (this.indent) {
264 TransformerUtils.enableIndenting(transformer);
265 }
266 else {
267 TransformerUtils.disableIndenting(transformer);
268 }
269 }
270
271
276 protected final void copyOutputProperties(Transformer transformer) {
277 if (this.outputProperties != null) {
278 Enumeration en = this.outputProperties.propertyNames();
279 while (en.hasMoreElements()) {
280 String name = (String ) en.nextElement();
281 transformer.setOutputProperty(name, this.outputProperties.getProperty(name));
282 }
283 }
284 }
285
286
291 protected final void copyModelParameters(Map model, Transformer transformer) {
292 copyMapEntriesToTransformerParameters(model, transformer);
293 }
294
295
301 protected void configureResponse(Map model, HttpServletResponse response, Transformer transformer) {
302 response.setContentType(transformer.getOutputProperty(OutputKeys.MEDIA_TYPE));
303 response.setCharacterEncoding(transformer.getOutputProperty(OutputKeys.ENCODING));
304 }
305
306
309 private Templates loadTemplates() throws ApplicationContextException {
310 Source stylesheetSource = getStylesheetSource();
311 try {
312 Templates templates = getTransformerFactory().newTemplates(stylesheetSource);
313 if (logger.isDebugEnabled()) {
314 logger.debug("Loading templates '" + templates + "'");
315 }
316 return templates;
317 }
318 catch (TransformerConfigurationException ex) {
319 throw new ApplicationContextException("Can't load stylesheet from '" + getUrl() + "'", ex);
320 }
321 finally {
322 closeSourceIfNecessary(stylesheetSource);
323 }
324 }
325
326
331 protected Transformer createTransformer(Templates templates) throws TransformerConfigurationException {
332 Transformer transformer = templates.newTransformer();
333 if (this.uriResolver != null) {
334 transformer.setURIResolver(this.uriResolver);
335 }
336 return transformer;
337 }
338
339
342 protected Source getStylesheetSource() {
343 String url = getUrl();
344 if (logger.isDebugEnabled()) {
345 logger.debug("Loading XSLT stylesheet from '" + url + "'");
346 }
347 try {
348 Resource stylesheetResource = getApplicationContext().getResource(url);
349 String systemId = url.substring(0, url.lastIndexOf('/') + 1);
350 return new StreamSource (stylesheetResource.getInputStream(), systemId);
351 }
352 catch (IOException ex) {
353 throw new ApplicationContextException("Can't load XSLT stylesheet from '" + url + "'", ex);
354 }
355 }
356
357
362 private void copyMapEntriesToTransformerParameters(Map map, Transformer transformer) {
363 for (Iterator iterator = map.entrySet().iterator(); iterator.hasNext();) {
364 Map.Entry entry = (Map.Entry ) iterator.next();
365 transformer.setParameter(ObjectUtils.nullSafeToString(entry.getKey()), entry.getValue());
366 }
367 }
368
369
373 private void closeSourceIfNecessary(Source source) {
374 if (source instanceof StreamSource ) {
375 StreamSource streamSource = (StreamSource ) source;
376
377 if (streamSource.getInputStream() != null) {
378 try {
379 streamSource.getInputStream().close();
380 }
381 catch (IOException e) {
382 logger.warn("Unable to close InputStream '" + streamSource.getInputStream() + "'");
383 }
384 }
385 else if (streamSource.getReader() != null) {
386 try {
387 streamSource.getReader().close();
388 }
389 catch (IOException e) {
390 logger.warn("Unable to close Reader '" + streamSource.getReader() + "'");
391 }
392 }
393 }
394 }
395
396 }
397 |
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