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.directive.StopCommand;
33 import org.apache.velocity.runtime.parser.Parser;
34 import org.apache.velocity.util.ClassUtils;
35 import org.apache.velocity.util.introspection.Info;
36 import org.apache.velocity.util.introspection.VelMethod;
37
38 /**
39 * ASTMethod.java
40 *
41 * Method support for references : $foo.method()
42 *
43 * NOTE :
44 *
45 * introspection is now done at render time.
46 *
47 * Please look at the Parser.jjt file which is
48 * what controls the generation of this class.
49 *
50 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
51 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
52 * @version $Id: ASTMethod.java 898032 2010-01-11 19:51:03Z nbubna $
53 */
54 public class ASTMethod extends SimpleNode
55 {
56 private String methodName = "";
57 private int paramCount = 0;
58
59 protected Info uberInfo;
60
61 /**
62 * Indicates if we are running in strict reference mode.
63 */
64 protected boolean strictRef = false;
65
66 /**
67 * @param id
68 */
69 public ASTMethod(int id)
70 {
71 super(id);
72 }
73
74 /**
75 * @param p
76 * @param id
77 */
78 public ASTMethod(Parser p, int id)
79 {
80 super(p, id);
81 }
82
83 /**
84 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
85 */
86 public Object jjtAccept(ParserVisitor visitor, Object data)
87 {
88 return visitor.visit(this, data);
89 }
90
91 /**
92 * simple init - init our subtree and get what we can from
93 * the AST
94 * @param context
95 * @param data
96 * @return The init result
97 * @throws TemplateInitException
98 */
99 public Object init( InternalContextAdapter context, Object data)
100 throws TemplateInitException
101 {
102 super.init( context, data );
103
104 /*
105 * make an uberinfo - saves new's later on
106 */
107
108 uberInfo = new Info(getTemplateName(),
109 getLine(),getColumn());
110 /*
111 * this is about all we can do
112 */
113
114 methodName = getFirstToken().image;
115 paramCount = jjtGetNumChildren() - 1;
116
117 strictRef = rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false);
118
119 return data;
120 }
121
122 /**
123 * invokes the method. Returns null if a problem, the
124 * actual return if the method returns something, or
125 * an empty string "" if the method returns void
126 * @param o
127 * @param context
128 * @return Result or null.
129 * @throws MethodInvocationException
130 */
131 public Object execute(Object o, InternalContextAdapter context)
132 throws MethodInvocationException
133 {
134 /*
135 * new strategy (strategery!) for introspection. Since we want
136 * to be thread- as well as context-safe, we *must* do it now,
137 * at execution time. There can be no in-node caching,
138 * but if we are careful, we can do it in the context.
139 */
140 Object [] params = new Object[paramCount];
141
142 /*
143 * sadly, we do need recalc the values of the args, as this can
144 * change from visit to visit
145 */
146 final Class[] paramClasses =
147 paramCount > 0 ? new Class[paramCount] : ArrayUtils.EMPTY_CLASS_ARRAY;
148
149 for (int j = 0; j < paramCount; j++)
150 {
151 params[j] = jjtGetChild(j + 1).value(context);
152 if (params[j] != null)
153 {
154 paramClasses[j] = params[j].getClass();
155 }
156 }
157
158 VelMethod method = ClassUtils.getMethod(methodName, params, paramClasses,
159 o, context, this, strictRef);
160 if (method == null) return null;
161
162 try
163 {
164 /*
165 * get the returned object. It may be null, and that is
166 * valid for something declared with a void return type.
167 * Since the caller is expecting something to be returned,
168 * as long as things are peachy, we can return an empty
169 * String so ASTReference() correctly figures out that
170 * all is well.
171 */
172
173 Object obj = method.invoke(o, params);
174
175 if (obj == null)
176 {
177 if( method.getReturnType() == Void.TYPE)
178 {
179 return "";
180 }
181 }
182
183 return obj;
184 }
185 catch( InvocationTargetException ite )
186 {
187 return handleInvocationException(o, context, ite.getTargetException());
188 }
189
190 /** Can also be thrown by method invocation **/
191 catch( IllegalArgumentException t )
192 {
193 return handleInvocationException(o, context, t);
194 }
195
196 /**
197 * pass through application level runtime exceptions
198 */
199 catch( RuntimeException e )
200 {
201 throw e;
202 }
203 catch( Exception e )
204 {
205 String msg = "ASTMethod.execute() : exception invoking method '"
206 + methodName + "' in " + o.getClass();
207 log.error(msg, e);
208 throw new VelocityException(msg, e);
209 }
210 }
211
212 private Object handleInvocationException(Object o, InternalContextAdapter context, Throwable t)
213 {
214 /*
215 * We let StopCommands go up to the directive they are for/from
216 */
217 if (t instanceof StopCommand)
218 {
219 throw (StopCommand)t;
220 }
221
222 /*
223 * In the event that the invocation of the method
224 * itself throws an exception, we want to catch that
225 * wrap it, and throw. We don't log here as we want to figure
226 * out which reference threw the exception, so do that
227 * above
228 */
229 else if (t instanceof Exception)
230 {
231 try
232 {
233 return EventHandlerUtil.methodException( rsvc, context, o.getClass(), methodName, (Exception) t );
234 }
235
236 /**
237 * If the event handler throws an exception, then wrap it
238 * in a MethodInvocationException. Don't pass through RuntimeExceptions like other
239 * similar catchall code blocks.
240 */
241 catch( Exception e )
242 {
243 throw new MethodInvocationException(
244 "Invocation of method '"
245 + methodName + "' in " + o.getClass()
246 + " threw exception "
247 + e.toString(),
248 e, methodName, getTemplateName(), this.getLine(), this.getColumn());
249 }
250 }
251
252 /*
253 * let non-Exception Throwables go...
254 */
255 else
256 {
257 /*
258 * no event cartridge to override. Just throw
259 */
260
261 throw new MethodInvocationException(
262 "Invocation of method '"
263 + methodName + "' in " + o.getClass()
264 + " threw exception "
265 + t.toString(),
266 t, methodName, getTemplateName(), this.getLine(), this.getColumn());
267 }
268 }
269
270 /**
271 * Internal class used as key for method cache. Combines
272 * ASTMethod fields with array of parameter classes. Has
273 * public access (and complete constructor) for unit test
274 * purposes.
275 * @since 1.5
276 */
277 public static class MethodCacheKey
278 {
279 private final String methodName;
280 private final Class[] params;
281
282 public MethodCacheKey(String methodName, Class[] params)
283 {
284 /**
285 * Should never be initialized with nulls, but to be safe we refuse
286 * to accept them.
287 */
288 this.methodName = (methodName != null) ? methodName : StringUtils.EMPTY;
289 this.params = (params != null) ? params : ArrayUtils.EMPTY_CLASS_ARRAY;
290 }
291
292 /**
293 * @see java.lang.Object#equals(java.lang.Object)
294 */
295 public boolean equals(Object o)
296 {
297 /**
298 * note we skip the null test for methodName and params
299 * due to the earlier test in the constructor
300 */
301 if (o instanceof MethodCacheKey)
302 {
303 final MethodCacheKey other = (MethodCacheKey) o;
304 if (params.length == other.params.length &&
305 methodName.equals(other.methodName))
306 {
307 for (int i = 0; i < params.length; ++i)
308 {
309 if (params[i] == null)
310 {
311 if (params[i] != other.params[i])
312 {
313 return false;
314 }
315 }
316 else if (!params[i].equals(other.params[i]))
317 {
318 return false;
319 }
320 }
321 return true;
322 }
323 }
324 return false;
325 }
326
327
328 /**
329 * @see java.lang.Object#hashCode()
330 */
331 public int hashCode()
332 {
333 int result = 17;
334
335 /**
336 * note we skip the null test for methodName and params
337 * due to the earlier test in the constructor
338 */
339 for (int i = 0; i < params.length; ++i)
340 {
341 final Class param = params[i];
342 if (param != null)
343 {
344 result = result * 37 + param.hashCode();
345 }
346 }
347
348 result = result * 37 + methodName.hashCode();
349
350 return result;
351 }
352 }
353
354 /**
355 * @return Returns the methodName.
356 * @since 1.5
357 */
358 public String getMethodName()
359 {
360 return methodName;
361 }
362
363
364 }