1 package org.apache.velocity.runtime.parser.node;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.lang.reflect.InvocationTargetException;
23
24 import org.apache.commons.lang.ArrayUtils;
25 import org.apache.commons.lang.StringUtils;
26 import org.apache.velocity.app.event.EventHandlerUtil;
27 import org.apache.velocity.context.InternalContextAdapter;
28 import org.apache.velocity.exception.MethodInvocationException;
29 import org.apache.velocity.exception.TemplateInitException;
30 import org.apache.velocity.exception.VelocityException;
31 import org.apache.velocity.runtime.RuntimeConstants;
32 import org.apache.velocity.runtime.parser.Parser;
33 import org.apache.velocity.util.introspection.Info;
34 import org.apache.velocity.util.introspection.IntrospectionCacheData;
35 import org.apache.velocity.util.introspection.VelMethod;
36
37 /**
38 * ASTMethod.java
39 *
40 * Method support for references : $foo.method()
41 *
42 * NOTE :
43 *
44 * introspection is now done at render time.
45 *
46 * Please look at the Parser.jjt file which is
47 * what controls the generation of this class.
48 *
49 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
50 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
51 * @version $Id: ASTMethod.java 720228 2008-11-24 16:58:33Z nbubna $
52 */
53 public class ASTMethod extends SimpleNode
54 {
55 private String methodName = "";
56 private int paramCount = 0;
57
58 protected Info uberInfo;
59
60 /**
61 * Indicates if we are running in strict reference mode.
62 */
63 protected boolean strictRef = false;
64
65 /**
66 * @param id
67 */
68 public ASTMethod(int id)
69 {
70 super(id);
71 }
72
73 /**
74 * @param p
75 * @param id
76 */
77 public ASTMethod(Parser p, int id)
78 {
79 super(p, id);
80 }
81
82 /**
83 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
84 */
85 public Object jjtAccept(ParserVisitor visitor, Object data)
86 {
87 return visitor.visit(this, data);
88 }
89
90 /**
91 * simple init - init our subtree and get what we can from
92 * the AST
93 * @param context
94 * @param data
95 * @return The init result
96 * @throws TemplateInitException
97 */
98 public Object init( InternalContextAdapter context, Object data)
99 throws TemplateInitException
100 {
101 super.init( context, data );
102
103 /*
104 * make an uberinfo - saves new's later on
105 */
106
107 uberInfo = new Info(getTemplateName(),
108 getLine(),getColumn());
109 /*
110 * this is about all we can do
111 */
112
113 methodName = getFirstToken().image;
114 paramCount = jjtGetNumChildren() - 1;
115
116 strictRef = rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false);
117
118 return data;
119 }
120
121 /**
122 * invokes the method. Returns null if a problem, the
123 * actual return if the method returns something, or
124 * an empty string "" if the method returns void
125 * @param o
126 * @param context
127 * @return Result or null.
128 * @throws MethodInvocationException
129 */
130 public Object execute(Object o, InternalContextAdapter context)
131 throws MethodInvocationException
132 {
133 /*
134 * new strategy (strategery!) for introspection. Since we want
135 * to be thread- as well as context-safe, we *must* do it now,
136 * at execution time. There can be no in-node caching,
137 * but if we are careful, we can do it in the context.
138 */
139
140 VelMethod method = null;
141
142 Object [] params = new Object[paramCount];
143
144 try
145 {
146 /*
147 * sadly, we do need recalc the values of the args, as this can
148 * change from visit to visit
149 */
150
151 final Class[] paramClasses = paramCount > 0 ? new Class[paramCount] : ArrayUtils.EMPTY_CLASS_ARRAY;
152
153 for (int j = 0; j < paramCount; j++)
154 {
155 params[j] = jjtGetChild(j + 1).value(context);
156
157 if (params[j] != null)
158 {
159 paramClasses[j] = params[j].getClass();
160 }
161 }
162
163 /*
164 * check the cache
165 */
166
167 MethodCacheKey mck = new MethodCacheKey(methodName, paramClasses);
168 IntrospectionCacheData icd = context.icacheGet( mck );
169
170 /*
171 * like ASTIdentifier, if we have cache information, and the
172 * Class of Object o is the same as that in the cache, we are
173 * safe.
174 */
175
176 if ( icd != null && (o != null && icd.contextData == o.getClass()) )
177 {
178
179 /*
180 * get the method from the cache
181 */
182
183 method = (VelMethod) icd.thingy;
184 }
185 else
186 {
187 /*
188 * otherwise, do the introspection, and then
189 * cache it
190 */
191
192 method = rsvc.getUberspect().getMethod(o, methodName, params, new Info(getTemplateName(), getLine(), getColumn()));
193
194 if ((method != null) && (o != null))
195 {
196 icd = new IntrospectionCacheData();
197 icd.contextData = o.getClass();
198 icd.thingy = method;
199
200 context.icachePut( mck, icd );
201 }
202 }
203
204 /*
205 * if we still haven't gotten the method, either we are calling
206 * a method that doesn't exist (which is fine...) or I screwed
207 * it up.
208 */
209
210 if (method == null)
211 {
212 if (strictRef)
213 {
214 // Create a parameter list for the exception error message
215 StringBuffer plist = new StringBuffer();
216 for (int i=0; i<params.length; i++)
217 {
218 Class param = paramClasses[i];
219 plist.append(param == null ? "null" : param.getName());
220 if (i < params.length -1) plist.append(", ");
221 }
222 throw new MethodInvocationException("Object '" + o.getClass().getName() +
223 "' does not contain method " + methodName + "(" + plist + ")",
224 null, methodName, uberInfo.getTemplateName(), uberInfo.getLine(), uberInfo.getColumn());
225 }
226 else
227 {
228 return null;
229 }
230 }
231 }
232 catch( MethodInvocationException mie )
233 {
234 /*
235 * this can come from the doIntrospection(), as the arg values
236 * are evaluated to find the right method signature. We just
237 * want to propogate it here, not do anything fancy
238 */
239
240 throw mie;
241 }
242 /**
243 * pass through application level runtime exceptions
244 */
245 catch( RuntimeException e )
246 {
247 throw e;
248 }
249 catch( Exception e )
250 {
251 /*
252 * can come from the doIntropection() also, from Introspector
253 */
254 String msg = "ASTMethod.execute() : exception from introspection";
255 log.error(msg, e);
256 throw new VelocityException(msg, e);
257 }
258
259 try
260 {
261 /*
262 * get the returned object. It may be null, and that is
263 * valid for something declared with a void return type.
264 * Since the caller is expecting something to be returned,
265 * as long as things are peachy, we can return an empty
266 * String so ASTReference() correctly figures out that
267 * all is well.
268 */
269
270 Object obj = method.invoke(o, params);
271
272 if (obj == null)
273 {
274 if( method.getReturnType() == Void.TYPE)
275 {
276 return "";
277 }
278 }
279
280 return obj;
281 }
282 catch( InvocationTargetException ite )
283 {
284 return handleInvocationException(o, context, ite.getTargetException());
285 }
286
287 /** Can also be thrown by method invocation **/
288 catch( IllegalArgumentException t )
289 {
290 return handleInvocationException(o, context, t);
291 }
292
293 /**
294 * pass through application level runtime exceptions
295 */
296 catch( RuntimeException e )
297 {
298 throw e;
299 }
300 catch( Exception e )
301 {
302 String msg = "ASTMethod.execute() : exception invoking method '"
303 + methodName + "' in " + o.getClass();
304 log.error(msg, e);
305 throw new VelocityException(msg, e);
306 }
307 }
308
309 private Object handleInvocationException(Object o, InternalContextAdapter context, Throwable t)
310 {
311 /*
312 * In the event that the invocation of the method
313 * itself throws an exception, we want to catch that
314 * wrap it, and throw. We don't log here as we want to figure
315 * out which reference threw the exception, so do that
316 * above
317 */
318
319 /*
320 * let non-Exception Throwables go...
321 */
322
323 if (t instanceof Exception)
324 {
325 try
326 {
327 return EventHandlerUtil.methodException( rsvc, context, o.getClass(), methodName, (Exception) t );
328 }
329
330 /**
331 * If the event handler throws an exception, then wrap it
332 * in a MethodInvocationException. Don't pass through RuntimeExceptions like other
333 * similar catchall code blocks.
334 */
335 catch( Exception e )
336 {
337 throw new MethodInvocationException(
338 "Invocation of method '"
339 + methodName + "' in " + o.getClass()
340 + " threw exception "
341 + e.toString(),
342 e, methodName, getTemplateName(), this.getLine(), this.getColumn());
343 }
344 }
345 else
346 {
347 /*
348 * no event cartridge to override. Just throw
349 */
350
351 throw new MethodInvocationException(
352 "Invocation of method '"
353 + methodName + "' in " + o.getClass()
354 + " threw exception "
355 + t.toString(),
356 t, methodName, getTemplateName(), this.getLine(), this.getColumn());
357 }
358 }
359
360 /**
361 * Internal class used as key for method cache. Combines
362 * ASTMethod fields with array of parameter classes. Has
363 * public access (and complete constructor) for unit test
364 * purposes.
365 * @since 1.5
366 */
367 public static class MethodCacheKey
368 {
369 private final String methodName;
370 private final Class[] params;
371
372 public MethodCacheKey(String methodName, Class[] params)
373 {
374 /**
375 * Should never be initialized with nulls, but to be safe we refuse
376 * to accept them.
377 */
378 this.methodName = (methodName != null) ? methodName : StringUtils.EMPTY;
379 this.params = (params != null) ? params : ArrayUtils.EMPTY_CLASS_ARRAY;
380 }
381
382 /**
383 * @see java.lang.Object#equals(java.lang.Object)
384 */
385 public boolean equals(Object o)
386 {
387 /**
388 * note we skip the null test for methodName and params
389 * due to the earlier test in the constructor
390 */
391 if (o instanceof MethodCacheKey)
392 {
393 final MethodCacheKey other = (MethodCacheKey) o;
394 if (params.length == other.params.length &&
395 methodName.equals(other.methodName))
396 {
397 for (int i = 0; i < params.length; ++i)
398 {
399 if (params[i] == null)
400 {
401 if (params[i] != other.params[i])
402 {
403 return false;
404 }
405 }
406 else if (!params[i].equals(other.params[i]))
407 {
408 return false;
409 }
410 }
411 return true;
412 }
413 }
414 return false;
415 }
416
417
418 /**
419 * @see java.lang.Object#hashCode()
420 */
421 public int hashCode()
422 {
423 int result = 17;
424
425 /**
426 * note we skip the null test for methodName and params
427 * due to the earlier test in the constructor
428 */
429 for (int i = 0; i < params.length; ++i)
430 {
431 final Class param = params[i];
432 if (param != null)
433 {
434 result = result * 37 + param.hashCode();
435 }
436 }
437
438 result = result * 37 + methodName.hashCode();
439
440 return result;
441 }
442 }
443
444 /**
445 * @return Returns the methodName.
446 * @since 1.5
447 */
448 public String getMethodName()
449 {
450 return methodName;
451 }
452
453
454 }