001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 /*
019 * $Id: ExtensionHandlerJavaClass.java 469672 2006-10-31 21:56:19Z minchau $
020 */
021
022 package org.apache.xalan.extensions;
023
024 import java.io.IOException;
025 import java.lang.reflect.Constructor;
026 import java.lang.reflect.InvocationTargetException;
027 import java.lang.reflect.Method;
028 import java.lang.reflect.Modifier;
029 import java.util.Vector;
030
031 import javax.xml.transform.TransformerException;
032
033 import org.apache.xalan.templates.ElemTemplateElement;
034 import org.apache.xalan.templates.Stylesheet;
035 import org.apache.xalan.trace.ExtensionEvent;
036 import org.apache.xalan.transformer.TransformerImpl;
037 import org.apache.xpath.functions.FuncExtFunction;
038 import org.apache.xpath.objects.XObject;
039
040 /**
041 * Represents an extension namespace for XPath that handles java classes.
042 * It is recommended that the class URI be of the form:
043 * <pre>
044 * xalan://fully.qualified.class.name
045 * </pre>
046 * However, we do not enforce this. If the class name contains a
047 * a /, we only use the part to the right of the rightmost slash.
048 * In addition, we ignore any "class:" prefix.
049 * Provides functions to test a function's existence and call a function.
050 * Also provides functions to test an element's existence and call an
051 * element.
052 *
053 * @author <a href="mailto:garyp@firstech.com">Gary L Peskin</a>
054 * @xsl.usage internal
055 */
056
057 public class ExtensionHandlerJavaClass extends ExtensionHandlerJava
058 {
059
060 private Class m_classObj = null;
061
062 /**
063 * Provides a default Instance for use by elements that need to call
064 * an instance method.
065 */
066
067 private Object m_defaultInstance = null;
068
069
070 /**
071 * Construct a new extension namespace handler given all the information
072 * needed.
073 * @param namespaceUri the extension namespace URI that I'm implementing
074 * @param scriptLang language of code implementing the extension
075 * @param className the fully qualified class name of the class
076 */
077 public ExtensionHandlerJavaClass(String namespaceUri,
078 String scriptLang,
079 String className)
080 {
081 super(namespaceUri, scriptLang, className);
082 try
083 {
084 m_classObj = getClassForName(className);
085 }
086 catch (ClassNotFoundException e)
087 {
088 // For now, just let this go. We'll catch it when we try to invoke a method.
089 }
090 }
091
092
093 /**
094 * Tests whether a certain function name is known within this namespace.
095 * Simply looks for a method with the appropriate name. There is
096 * no information regarding the arguments to the function call or
097 * whether the method implementing the function is a static method or
098 * an instance method.
099 * @param function name of the function being tested
100 * @return true if its known, false if not.
101 */
102
103 public boolean isFunctionAvailable(String function)
104 {
105 Method[] methods = m_classObj.getMethods();
106 int nMethods = methods.length;
107 for (int i = 0; i < nMethods; i++)
108 {
109 if (methods[i].getName().equals(function))
110 return true;
111 }
112 return false;
113 }
114
115
116 /**
117 * Tests whether a certain element name is known within this namespace.
118 * Looks for a method with the appropriate name and signature.
119 * This method examines both static and instance methods.
120 * @param element name of the element being tested
121 * @return true if its known, false if not.
122 */
123
124 public boolean isElementAvailable(String element)
125 {
126 Method[] methods = m_classObj.getMethods();
127 int nMethods = methods.length;
128 for (int i = 0; i < nMethods; i++)
129 {
130 if (methods[i].getName().equals(element))
131 {
132 Class[] paramTypes = methods[i].getParameterTypes();
133 if ( (paramTypes.length == 2)
134 && paramTypes[0].isAssignableFrom(
135 org.apache.xalan.extensions.XSLProcessorContext.class)
136 && paramTypes[1].isAssignableFrom(
137 org.apache.xalan.templates.ElemExtensionCall.class) )
138 {
139 return true;
140 }
141 }
142 }
143 return false;
144 }
145
146 /**
147 * Process a call to a function in the java class represented by
148 * this <code>ExtensionHandlerJavaClass<code>.
149 * There are three possible types of calls:
150 * <pre>
151 * Constructor:
152 * classns:new(arg1, arg2, ...)
153 *
154 * Static method:
155 * classns:method(arg1, arg2, ...)
156 *
157 * Instance method:
158 * classns:method(obj, arg1, arg2, ...)
159 * </pre>
160 * We use the following rules to determine the type of call made:
161 * <ol type="1">
162 * <li>If the function name is "new", call the best constructor for
163 * class represented by the namespace URI</li>
164 * <li>If the first argument to the function is of the class specified
165 * in the namespace or is a subclass of that class, look for the best
166 * method of the class specified in the namespace with the specified
167 * arguments. Compare all static and instance methods with the correct
168 * method name. For static methods, use all arguments in the compare.
169 * For instance methods, use all arguments after the first.</li>
170 * <li>Otherwise, select the best static or instance method matching
171 * all of the arguments. If the best method is an instance method,
172 * call the function using a default object, creating it if needed.</li>
173 * </ol>
174 *
175 * @param funcName Function name.
176 * @param args The arguments of the function call.
177 * @param methodKey A key that uniquely identifies this class and method call.
178 * @param exprContext The context in which this expression is being executed.
179 * @return the return value of the function evaluation.
180 * @throws TransformerException
181 */
182
183 public Object callFunction (String funcName,
184 Vector args,
185 Object methodKey,
186 ExpressionContext exprContext)
187 throws TransformerException
188 {
189
190 Object[] methodArgs;
191 Object[][] convertedArgs;
192 Class[] paramTypes;
193
194 try
195 {
196 TransformerImpl trans = (exprContext != null) ?
197 (TransformerImpl)exprContext.getXPathContext().getOwnerObject() : null;
198 if (funcName.equals("new")) { // Handle constructor call
199
200 methodArgs = new Object[args.size()];
201 convertedArgs = new Object[1][];
202 for (int i = 0; i < methodArgs.length; i++)
203 {
204 methodArgs[i] = args.get(i);
205 }
206 Constructor c = null;
207 if (methodKey != null)
208 c = (Constructor) getFromCache(methodKey, null, methodArgs);
209
210 if (c != null && !trans.getDebug())
211 {
212 try
213 {
214 paramTypes = c.getParameterTypes();
215 MethodResolver.convertParams(methodArgs, convertedArgs,
216 paramTypes, exprContext);
217 return c.newInstance(convertedArgs[0]);
218 }
219 catch (InvocationTargetException ite)
220 {
221 throw ite;
222 }
223 catch(Exception e)
224 {
225 // Must not have been the right one
226 }
227 }
228 c = MethodResolver.getConstructor(m_classObj,
229 methodArgs,
230 convertedArgs,
231 exprContext);
232 if (methodKey != null)
233 putToCache(methodKey, null, methodArgs, c);
234
235 if (trans != null && trans.getDebug()) {
236 trans.getTraceManager().fireExtensionEvent(new
237 ExtensionEvent(trans, c, convertedArgs[0]));
238 Object result;
239 try {
240 result = c.newInstance(convertedArgs[0]);
241 } catch (Exception e) {
242 throw e;
243 } finally {
244 trans.getTraceManager().fireExtensionEndEvent(new
245 ExtensionEvent(trans, c, convertedArgs[0]));
246 }
247 return result;
248 } else
249 return c.newInstance(convertedArgs[0]);
250 }
251
252 else
253 {
254
255 int resolveType;
256 Object targetObject = null;
257 methodArgs = new Object[args.size()];
258 convertedArgs = new Object[1][];
259 for (int i = 0; i < methodArgs.length; i++)
260 {
261 methodArgs[i] = args.get(i);
262 }
263 Method m = null;
264 if (methodKey != null)
265 m = (Method) getFromCache(methodKey, null, methodArgs);
266
267 if (m != null && !trans.getDebug())
268 {
269 try
270 {
271 paramTypes = m.getParameterTypes();
272 MethodResolver.convertParams(methodArgs, convertedArgs,
273 paramTypes, exprContext);
274 if (Modifier.isStatic(m.getModifiers()))
275 return m.invoke(null, convertedArgs[0]);
276 else
277 {
278 // This is tricky. We get the actual number of target arguments (excluding any
279 // ExpressionContext). If we passed in the same number, we need the implied object.
280 int nTargetArgs = convertedArgs[0].length;
281 if (ExpressionContext.class.isAssignableFrom(paramTypes[0]))
282 nTargetArgs--;
283 if (methodArgs.length <= nTargetArgs)
284 return m.invoke(m_defaultInstance, convertedArgs[0]);
285 else
286 {
287 targetObject = methodArgs[0];
288
289 if (targetObject instanceof XObject)
290 targetObject = ((XObject) targetObject).object();
291
292 return m.invoke(targetObject, convertedArgs[0]);
293 }
294 }
295 }
296 catch (InvocationTargetException ite)
297 {
298 throw ite;
299 }
300 catch(Exception e)
301 {
302 // Must not have been the right one
303 }
304 }
305
306 if (args.size() > 0)
307 {
308 targetObject = methodArgs[0];
309
310 if (targetObject instanceof XObject)
311 targetObject = ((XObject) targetObject).object();
312
313 if (m_classObj.isAssignableFrom(targetObject.getClass()))
314 resolveType = MethodResolver.DYNAMIC;
315 else
316 resolveType = MethodResolver.STATIC_AND_INSTANCE;
317 }
318 else
319 {
320 targetObject = null;
321 resolveType = MethodResolver.STATIC_AND_INSTANCE;
322 }
323
324 m = MethodResolver.getMethod(m_classObj,
325 funcName,
326 methodArgs,
327 convertedArgs,
328 exprContext,
329 resolveType);
330 if (methodKey != null)
331 putToCache(methodKey, null, methodArgs, m);
332
333 if (MethodResolver.DYNAMIC == resolveType) { // First argument was object type
334 if (trans != null && trans.getDebug()) {
335 trans.getTraceManager().fireExtensionEvent(m, targetObject,
336 convertedArgs[0]);
337 Object result;
338 try {
339 result = m.invoke(targetObject, convertedArgs[0]);
340 } catch (Exception e) {
341 throw e;
342 } finally {
343 trans.getTraceManager().fireExtensionEndEvent(m, targetObject,
344 convertedArgs[0]);
345 }
346 return result;
347 } else
348 return m.invoke(targetObject, convertedArgs[0]);
349 }
350 else // First arg was not object. See if we need the implied object.
351 {
352 if (Modifier.isStatic(m.getModifiers())) {
353 if (trans != null && trans.getDebug()) {
354 trans.getTraceManager().fireExtensionEvent(m, null,
355 convertedArgs[0]);
356 Object result;
357 try {
358 result = m.invoke(null, convertedArgs[0]);
359 } catch (Exception e) {
360 throw e;
361 } finally {
362 trans.getTraceManager().fireExtensionEndEvent(m, null,
363 convertedArgs[0]);
364 }
365 return result;
366 } else
367 return m.invoke(null, convertedArgs[0]);
368 }
369 else
370 {
371 if (null == m_defaultInstance)
372 {
373 if (trans != null && trans.getDebug()) {
374 trans.getTraceManager().fireExtensionEvent(new
375 ExtensionEvent(trans, m_classObj));
376 try {
377 m_defaultInstance = m_classObj.newInstance();
378 } catch (Exception e) {
379 throw e;
380 } finally {
381 trans.getTraceManager().fireExtensionEndEvent(new
382 ExtensionEvent(trans, m_classObj));
383 }
384 } else
385 m_defaultInstance = m_classObj.newInstance();
386 }
387 if (trans != null && trans.getDebug()) {
388 trans.getTraceManager().fireExtensionEvent(m, m_defaultInstance,
389 convertedArgs[0]);
390 Object result;
391 try {
392 result = m.invoke(m_defaultInstance, convertedArgs[0]);
393 } catch (Exception e) {
394 throw e;
395 } finally {
396 trans.getTraceManager().fireExtensionEndEvent(m,
397 m_defaultInstance, convertedArgs[0]);
398 }
399 return result;
400 } else
401 return m.invoke(m_defaultInstance, convertedArgs[0]);
402 }
403 }
404
405 }
406 }
407 catch (InvocationTargetException ite)
408 {
409 Throwable resultException = ite;
410 Throwable targetException = ite.getTargetException();
411
412 if (targetException instanceof TransformerException)
413 throw ((TransformerException)targetException);
414 else if (targetException != null)
415 resultException = targetException;
416
417 throw new TransformerException(resultException);
418 }
419 catch (Exception e)
420 {
421 // e.printStackTrace();
422 throw new TransformerException(e);
423 }
424 }
425
426 /**
427 * Process a call to an XPath extension function
428 *
429 * @param extFunction The XPath extension function
430 * @param args The arguments of the function call.
431 * @param exprContext The context in which this expression is being executed.
432 * @return the return value of the function evaluation.
433 * @throws TransformerException
434 */
435 public Object callFunction(FuncExtFunction extFunction,
436 Vector args,
437 ExpressionContext exprContext)
438 throws TransformerException
439 {
440 return callFunction(extFunction.getFunctionName(), args,
441 extFunction.getMethodKey(), exprContext);
442 }
443
444 /**
445 * Process a call to this extension namespace via an element. As a side
446 * effect, the results are sent to the TransformerImpl's result tree.
447 * We invoke the static or instance method in the class represented by
448 * by the namespace URI. If we don't already have an instance of this class,
449 * we create one upon the first call.
450 *
451 * @param localPart Element name's local part.
452 * @param element The extension element being processed.
453 * @param transformer Handle to TransformerImpl.
454 * @param stylesheetTree The compiled stylesheet tree.
455 * @param methodKey A key that uniquely identifies this element call.
456 * @throws IOException if loading trouble
457 * @throws TransformerException if parsing trouble
458 */
459
460 public void processElement(String localPart,
461 ElemTemplateElement element,
462 TransformerImpl transformer,
463 Stylesheet stylesheetTree,
464 Object methodKey)
465 throws TransformerException, IOException
466 {
467 Object result = null;
468
469 Method m = (Method) getFromCache(methodKey, null, null);
470 if (null == m)
471 {
472 try
473 {
474 m = MethodResolver.getElementMethod(m_classObj, localPart);
475 if ( (null == m_defaultInstance) &&
476 !Modifier.isStatic(m.getModifiers()) ) {
477 if (transformer.getDebug()) {
478 transformer.getTraceManager().fireExtensionEvent(
479 new ExtensionEvent(transformer, m_classObj));
480 try {
481 m_defaultInstance = m_classObj.newInstance();
482 } catch (Exception e) {
483 throw e;
484 } finally {
485 transformer.getTraceManager().fireExtensionEndEvent(
486 new ExtensionEvent(transformer, m_classObj));
487 }
488 } else
489 m_defaultInstance = m_classObj.newInstance();
490 }
491 }
492 catch (Exception e)
493 {
494 // e.printStackTrace ();
495 throw new TransformerException (e.getMessage (), e);
496 }
497 putToCache(methodKey, null, null, m);
498 }
499
500 XSLProcessorContext xpc = new XSLProcessorContext(transformer,
501 stylesheetTree);
502
503 try
504 {
505 if (transformer.getDebug()) {
506 transformer.getTraceManager().fireExtensionEvent(m, m_defaultInstance,
507 new Object[] {xpc, element});
508 try {
509 result = m.invoke(m_defaultInstance, new Object[] {xpc, element});
510 } catch (Exception e) {
511 throw e;
512 } finally {
513 transformer.getTraceManager().fireExtensionEndEvent(m,
514 m_defaultInstance, new Object[] {xpc, element});
515 }
516 } else
517 result = m.invoke(m_defaultInstance, new Object[] {xpc, element});
518 }
519 catch (InvocationTargetException e)
520 {
521 Throwable targetException = e.getTargetException();
522
523 if (targetException instanceof TransformerException)
524 throw (TransformerException)targetException;
525 else if (targetException != null)
526 throw new TransformerException (targetException.getMessage (),
527 targetException);
528 else
529 throw new TransformerException (e.getMessage (), e);
530 }
531 catch (Exception e)
532 {
533 // e.printStackTrace ();
534 throw new TransformerException (e.getMessage (), e);
535 }
536
537 if (result != null)
538 {
539 xpc.outputToResultTree (stylesheetTree, result);
540 }
541
542 }
543
544 }