001 // Copyright 2006, 2007, 2008 The Apache Software Foundation
002 //
003 // Licensed under the Apache License, Version 2.0 (the "License");
004 // you may not use this file except in compliance with the License.
005 // You may obtain a copy of the License at
006 //
007 // http://www.apache.org/licenses/LICENSE-2.0
008 //
009 // Unless required by applicable law or agreed to in writing, software
010 // distributed under the License is distributed on an "AS IS" BASIS,
011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012 // See the License for the specific language governing permissions and
013 // limitations under the License.
014
015 package org.apache.tapestry5.ioc.internal.services;
016
017 import javassist.*;
018 import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newMap;
019 import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newSet;
020 import org.apache.tapestry5.ioc.internal.util.Defense;
021 import org.apache.tapestry5.ioc.internal.util.InternalUtils;
022 import org.apache.tapestry5.ioc.services.ClassFab;
023 import org.apache.tapestry5.ioc.services.ClassFabUtils;
024 import org.apache.tapestry5.ioc.services.MethodIterator;
025 import org.apache.tapestry5.ioc.services.MethodSignature;
026 import org.slf4j.Logger;
027
028 import static java.lang.String.format;
029 import java.lang.reflect.Modifier;
030 import java.util.Formatter;
031 import java.util.Map;
032 import java.util.Set;
033
034 /**
035 * Implementation of {@link org.apache.tapestry5.ioc.services.ClassFab}. Hides, as much as possible, the underlying
036 * library (Javassist).
037 */
038 public class ClassFabImpl extends AbstractFab implements ClassFab
039 {
040 private static final Map<Class, String> DEFAULT_RETURN = newMap();
041
042 static
043 {
044 DEFAULT_RETURN.put(boolean.class, "false");
045 DEFAULT_RETURN.put(long.class, "0L");
046 DEFAULT_RETURN.put(float.class, "0.0f");
047 DEFAULT_RETURN.put(double.class, "0.0d");
048 }
049
050 /**
051 * Add fields, methods, and constructors are added, their psuedo-code is appended to this description, which is used
052 * by toString().
053 */
054 private final StringBuilder description = new StringBuilder();
055
056 private final Formatter formatter = new Formatter(description);
057
058 private final Set<MethodSignature> addedSignatures = newSet();
059
060 public ClassFabImpl(CtClassSource source, CtClass ctClass, Logger logger)
061 {
062 super(source, ctClass, logger);
063 }
064
065 /**
066 * Returns a representation of the fabricated class, including inheritance, fields, constructors, methods and method
067 * bodies.
068 */
069 @Override
070 public String toString()
071 {
072 StringBuilder buffer = new StringBuilder("ClassFab[\n");
073
074 try
075 {
076 buffer.append(buildClassAndInheritance());
077
078 buffer.append(description.toString());
079 }
080 catch (Exception ex)
081 {
082 buffer.append(" *** ");
083 buffer.append(ex);
084 }
085
086 buffer.append("\n]");
087
088 return buffer.toString();
089 }
090
091 private String buildClassAndInheritance() throws NotFoundException
092 {
093 StringBuilder buffer = new StringBuilder();
094
095 buffer.append(Modifier.toString(getCtClass().getModifiers()));
096 buffer.append(" class ");
097 buffer.append(getName());
098 buffer.append(" extends ");
099 buffer.append(getCtClass().getSuperclass().getName());
100 buffer.append("\n");
101
102 CtClass[] interfaces = getCtClass().getInterfaces();
103
104 if (interfaces.length > 0)
105 {
106 buffer.append(" implements ");
107
108 for (int i = 0; i < interfaces.length; i++)
109 {
110 if (i > 0) buffer.append(", ");
111
112 buffer.append(interfaces[i].getName());
113 }
114
115 buffer.append("\n\n");
116 }
117
118 return buffer.toString();
119 }
120
121 /**
122 * Returns the name of the class fabricated by this instance.
123 */
124 String getName()
125 {
126 return getCtClass().getName();
127 }
128
129 public void addField(String name, Class type)
130 {
131 addField(name, Modifier.PRIVATE, type);
132 }
133
134 public void addField(String name, int modifiers, Class type)
135 {
136 lock.check();
137
138 CtClass ctType = toCtClass(type);
139
140 try
141 {
142 CtField field = new CtField(ctType, name, getCtClass());
143 field.setModifiers(modifiers);
144
145 getCtClass().addField(field);
146 }
147 catch (CannotCompileException ex)
148 {
149 // Have yet to find a way to make this happen!
150 throw new RuntimeException(ServiceMessages.unableToAddField(name, getCtClass(), ex), ex);
151 }
152
153 formatter.format("%s %s %s;\n\n", Modifier.toString(modifiers), ClassFabUtils
154 .toJavaClassName(type), name);
155 }
156
157 public void proxyMethodsToDelegate(Class serviceInterface, String delegateExpression,
158 String toString)
159 {
160 lock.check();
161
162 addInterface(serviceInterface);
163
164 MethodIterator mi = new MethodIterator(serviceInterface);
165
166 while (mi.hasNext())
167 {
168 MethodSignature sig = mi.next();
169
170 // ($r) properly handles void methods for us, which keeps this simple.
171
172 String body = format("return ($r) %s.%s($$);", delegateExpression, sig.getName());
173
174 addMethod(Modifier.PUBLIC, sig, body);
175 }
176
177 if (!mi.getToString()) addToString(toString);
178 }
179
180 public void addToString(String toString)
181 {
182 lock.check();
183
184 MethodSignature sig = new MethodSignature(String.class, "toString", null, null);
185
186 // TODO: Very simple quoting here, will break down if the string itself contains
187 // double quotes or various other characters that need escaping.
188
189 addMethod(Modifier.PUBLIC, sig, format("return \"%s\";", toString));
190 }
191
192 public void addMethod(int modifiers, MethodSignature ms, String body)
193 {
194 lock.check();
195
196 if (addedSignatures.contains(ms))
197 throw new RuntimeException(ServiceMessages.duplicateMethodInClass(ms, this));
198
199 CtClass ctReturnType = toCtClass(ms.getReturnType());
200
201 CtClass[] ctParameters = toCtClasses(ms.getParameterTypes());
202 CtClass[] ctExceptions = toCtClasses(ms.getExceptionTypes());
203
204 CtMethod method = new CtMethod(ctReturnType, ms.getName(), ctParameters, getCtClass());
205
206 try
207 {
208 method.setModifiers(modifiers);
209 method.setBody(body);
210 method.setExceptionTypes(ctExceptions);
211
212 getCtClass().addMethod(method);
213 }
214 catch (Exception ex)
215 {
216 throw new RuntimeException(ServiceMessages.unableToAddMethod(ms, getCtClass(), ex), ex);
217 }
218
219 addedSignatures.add(ms);
220
221 // modifiers, return type, name
222
223 formatter.format("%s %s %s", Modifier.toString(modifiers), ClassFabUtils
224 .toJavaClassName(ms.getReturnType()), ms.getName());
225
226 // parameters, exceptions and body from this:
227 addMethodDetailsToDescription(ms.getParameterTypes(), ms.getExceptionTypes(), body);
228
229 description.append("\n\n");
230 }
231
232 public void addNoOpMethod(MethodSignature signature)
233 {
234 lock.check();
235
236 Class returnType = signature.getReturnType();
237
238 if (returnType.equals(void.class))
239 {
240 addMethod(Modifier.PUBLIC, signature, "return;");
241 return;
242 }
243
244 String value = "null";
245 if (returnType.isPrimitive())
246 {
247 value = DEFAULT_RETURN.get(returnType);
248 if (value == null) value = "0";
249 }
250
251 addMethod(Modifier.PUBLIC, signature, "return " + value + ";");
252 }
253
254 public void addConstructor(Class[] parameterTypes, Class[] exceptions, String body)
255 {
256 Defense.notBlank(body, "body");
257
258 lock.check();
259
260 CtClass[] ctParameters = toCtClasses(parameterTypes);
261 CtClass[] ctExceptions = toCtClasses(exceptions);
262
263 try
264 {
265 CtConstructor constructor = new CtConstructor(ctParameters, getCtClass());
266 constructor.setExceptionTypes(ctExceptions);
267 constructor.setBody(body);
268
269 getCtClass().addConstructor(constructor);
270 }
271 catch (Exception ex)
272 {
273 throw new RuntimeException(ServiceMessages.unableToAddConstructor(getCtClass(), ex), ex);
274 }
275
276 description.append("public ");
277
278 // This isn't quite right; we should strip the package portion off of the name.
279 // However, fabricated classes are almost always in the "default" package, so
280 // this is OK.
281
282 description.append(getName());
283
284 addMethodDetailsToDescription(parameterTypes, exceptions, body);
285
286 description.append("\n\n");
287 }
288
289 /**
290 * Adds a listing of method (or constructor) parameters and thrown exceptions, and the body, to the description
291 *
292 * @param parameterTypes types of method parameters, or null
293 * @param exceptions types of throw exceptions, or null
294 * @param body body of method or constructor
295 */
296 private void addMethodDetailsToDescription(Class[] parameterTypes, Class[] exceptions,
297 String body)
298 {
299 description.append("(");
300
301 int count = InternalUtils.size(parameterTypes);
302 for (int i = 0; i < count; i++)
303 {
304 if (i > 0) description.append(", ");
305
306 description.append(ClassFabUtils.toJavaClassName(parameterTypes[i]));
307
308 description.append(" $");
309 description.append(i + 1);
310 }
311
312 description.append(")");
313
314 count = InternalUtils.size(exceptions);
315 for (int i = 0; i < count; i++)
316 {
317 if (i == 0)
318 description.append("\n throws ");
319 else
320 description.append(", ");
321
322 // Since this can never be an array type, we don't need to use getJavaClassName
323
324 description.append(exceptions[i].getName());
325 }
326
327 description.append("\n");
328 description.append(body);
329 }
330 }