001// Copyright 2006, 2007, 2008, 2010 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
015package org.apache.tapestry5.ioc.internal.services;
016
017import static java.lang.String.format;
018import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newMap;
019import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newSet;
020
021import java.lang.annotation.Annotation;
022import java.lang.reflect.Method;
023import java.lang.reflect.Modifier;
024import java.util.Formatter;
025import java.util.List;
026import java.util.Map;
027import java.util.Set;
028
029import javassist.CannotCompileException;
030import javassist.CtClass;
031import javassist.CtConstructor;
032import javassist.CtField;
033import javassist.CtMethod;
034import javassist.NotFoundException;
035import javassist.bytecode.AnnotationsAttribute;
036import javassist.bytecode.ClassFile;
037import javassist.bytecode.ConstPool;
038import javassist.bytecode.MethodInfo;
039import javassist.bytecode.ParameterAnnotationsAttribute;
040import javassist.bytecode.annotation.MemberValue;
041
042import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
043import org.apache.tapestry5.ioc.internal.util.InternalUtils;
044import org.apache.tapestry5.ioc.services.ClassFab;
045import org.apache.tapestry5.ioc.services.ClassFabUtils;
046import org.apache.tapestry5.ioc.services.MethodIterator;
047import org.apache.tapestry5.ioc.services.MethodSignature;
048import org.slf4j.Logger;
049
050/**
051 * Implementation of {@link org.apache.tapestry5.ioc.services.ClassFab}. Hides, as much as possible, the underlying
052 * library (Javassist).
053 */
054@SuppressWarnings("all")
055public class ClassFabImpl extends AbstractFab implements ClassFab
056{
057    private static final Map<Class, String> DEFAULT_RETURN = newMap();
058
059    static
060    {
061        DEFAULT_RETURN.put(boolean.class, "false");
062        DEFAULT_RETURN.put(long.class, "0L");
063        DEFAULT_RETURN.put(float.class, "0.0f");
064        DEFAULT_RETURN.put(double.class, "0.0d");
065    }
066
067    /**
068     * Add fields, methods, and constructors are added, their psuedo-code is appended to this description, which is used
069     * by toString().
070     */
071    private final StringBuilder description = new StringBuilder();
072
073    private final Formatter formatter = new Formatter(description);
074
075    private final Set<MethodSignature> addedSignatures = newSet();
076
077    public ClassFabImpl(CtClassSource source, CtClass ctClass, Logger logger)
078    {
079        super(source, ctClass, logger);
080    }
081
082    /**
083     * Returns a representation of the fabricated class, including inheritance, fields, constructors, methods and method
084     * bodies.
085     */
086    @Override
087    public String toString()
088    {
089        StringBuilder buffer = new StringBuilder("ClassFab[\n");
090
091        try
092        {
093            buffer.append(buildClassAndInheritance());
094
095            buffer.append(description.toString());
096        }
097        catch (Exception ex)
098        {
099            buffer.append(" *** ");
100            buffer.append(ex);
101        }
102
103        buffer.append("\n]");
104
105        return buffer.toString();
106    }
107
108    private String buildClassAndInheritance() throws NotFoundException
109    {
110        StringBuilder buffer = new StringBuilder();
111
112        buffer.append(Modifier.toString(getCtClass().getModifiers()));
113        buffer.append(" class ");
114        buffer.append(getName());
115        buffer.append(" extends ");
116        buffer.append(getCtClass().getSuperclass().getName());
117        buffer.append("\n");
118
119        CtClass[] interfaces = getCtClass().getInterfaces();
120
121        if (interfaces.length > 0)
122        {
123            buffer.append("  implements ");
124
125            for (int i = 0; i < interfaces.length; i++)
126            {
127                if (i > 0)
128                    buffer.append(", ");
129
130                buffer.append(interfaces[i].getName());
131            }
132
133            buffer.append("\n\n");
134        }
135
136        return buffer.toString();
137    }
138
139    /**
140     * Returns the name of the class fabricated by this instance.
141     */
142    String getName()
143    {
144        return getCtClass().getName();
145    }
146
147    public void addField(String name, Class type)
148    {
149        addField(name, Modifier.PRIVATE, type);
150    }
151
152    public void addField(String name, int modifiers, Class type)
153    {
154        lock.check();
155
156        CtClass ctType = toCtClass(type);
157
158        try
159        {
160            CtField field = new CtField(ctType, name, getCtClass());
161            field.setModifiers(modifiers);
162
163            getCtClass().addField(field);
164        }
165        catch (CannotCompileException ex)
166        {
167            // Have yet to find a way to make this happen!
168            throw new RuntimeException(ServiceMessages.unableToAddField(name, getCtClass(), ex), ex);
169        }
170
171        formatter.format("%s %s %s;\n\n", Modifier.toString(modifiers), ClassFabUtils.toJavaClassName(type), name);
172    }
173
174    public void proxyMethodsToDelegate(Class serviceInterface, String delegateExpression, String toString)
175    {
176        lock.check();
177
178        addInterface(serviceInterface);
179
180        MethodIterator mi = new MethodIterator(serviceInterface);
181
182        while (mi.hasNext())
183        {
184            MethodSignature sig = mi.next();
185
186            // ($r) properly handles void methods for us, which keeps this simple.
187
188            String body = format("return ($r) %s.%s($$);", delegateExpression, sig.getName());
189
190            addMethod(Modifier.PUBLIC, sig, body);
191        }
192
193        if (!mi.getToString())
194            addToString(toString);
195    }
196
197    public void addToString(String toString)
198    {
199        lock.check();
200
201        MethodSignature sig = new MethodSignature(String.class, "toString", null, null);
202
203        // TODO: Very simple quoting here, will break down if the string itself contains
204        // double quotes or various other characters that need escaping.
205
206        addMethod(Modifier.PUBLIC, sig, format("return \"%s\";", toString));
207    }
208
209    public void addMethod(int modifiers, MethodSignature ms, String body)
210    {
211        lock.check();
212
213        if (addedSignatures.contains(ms))
214            throw new RuntimeException(ServiceMessages.duplicateMethodInClass(ms, this));
215
216        CtClass ctReturnType = toCtClass(ms.getReturnType());
217
218        CtClass[] ctParameters = toCtClasses(ms.getParameterTypes());
219        CtClass[] ctExceptions = toCtClasses(ms.getExceptionTypes());
220
221        CtMethod method = new CtMethod(ctReturnType, ms.getName(), ctParameters, getCtClass());
222
223        try
224        {
225            method.setModifiers(modifiers);
226            method.setBody(body);
227            method.setExceptionTypes(ctExceptions);
228
229            getCtClass().addMethod(method);
230        }
231        catch (Exception ex)
232        {
233            throw new RuntimeException(ServiceMessages.unableToAddMethod(ms, getCtClass(), ex), ex);
234        }
235
236        addedSignatures.add(ms);
237
238        // modifiers, return type, name
239
240        formatter.format("%s %s %s", Modifier.toString(modifiers), ClassFabUtils.toJavaClassName(ms.getReturnType()),
241                ms.getName());
242
243        // parameters, exceptions and body from this:
244        addMethodDetailsToDescription(ms.getParameterTypes(), ms.getExceptionTypes(), body);
245
246        description.append("\n\n");
247    }
248
249    public void addNoOpMethod(MethodSignature signature)
250    {
251        lock.check();
252
253        Class returnType = signature.getReturnType();
254
255        if (returnType.equals(void.class))
256        {
257            addMethod(Modifier.PUBLIC, signature, "return;");
258            return;
259        }
260
261        String value = "null";
262        if (returnType.isPrimitive())
263        {
264            value = DEFAULT_RETURN.get(returnType);
265            if (value == null)
266                value = "0";
267        }
268
269        addMethod(Modifier.PUBLIC, signature, "return " + value + ";");
270    }
271
272    public void addConstructor(Class[] parameterTypes, Class[] exceptions, String body)
273    {
274        assert InternalUtils.isNonBlank(body);
275        lock.check();
276
277        CtClass[] ctParameters = toCtClasses(parameterTypes);
278        CtClass[] ctExceptions = toCtClasses(exceptions);
279
280        try
281        {
282            CtConstructor constructor = new CtConstructor(ctParameters, getCtClass());
283            constructor.setExceptionTypes(ctExceptions);
284            constructor.setBody(body);
285
286            getCtClass().addConstructor(constructor);
287        }
288        catch (Exception ex)
289        {
290            throw new RuntimeException(ServiceMessages.unableToAddConstructor(getCtClass(), ex), ex);
291        }
292
293        description.append("public ");
294
295        // This isn't quite right; we should strip the package portion off of the name.
296        // However, fabricated classes are almost always in the "default" package, so
297        // this is OK.
298
299        description.append(getName());
300
301        addMethodDetailsToDescription(parameterTypes, exceptions, body);
302
303        description.append("\n\n");
304    }
305
306    /**
307     * Adds a listing of method (or constructor) parameters and thrown exceptions, and the body, to the description
308     * 
309     * @param parameterTypes
310     *            types of method parameters, or null
311     * @param exceptions
312     *            types of throw exceptions, or null
313     * @param body
314     *            body of method or constructor
315     */
316    private void addMethodDetailsToDescription(Class[] parameterTypes, Class[] exceptions, String body)
317    {
318        description.append("(");
319
320        int count = InternalUtils.size(parameterTypes);
321        for (int i = 0; i < count; i++)
322        {
323            if (i > 0)
324                description.append(", ");
325
326            description.append(ClassFabUtils.toJavaClassName(parameterTypes[i]));
327
328            description.append(" $");
329            description.append(i + 1);
330        }
331
332        description.append(")");
333
334        count = InternalUtils.size(exceptions);
335        for (int i = 0; i < count; i++)
336        {
337            if (i == 0)
338                description.append("\n  throws ");
339            else
340                description.append(", ");
341
342            // Since this can never be an array type, we don't need to use getJavaClassName
343
344            description.append(exceptions[i].getName());
345        }
346
347        description.append("\n");
348        description.append(body);
349    }
350    
351    public void copyClassAnnotationsFromDelegate(Class delegateClass)
352    {
353        lock.check();
354        
355        for (Annotation annotation : delegateClass.getAnnotations())
356        {
357            try
358            {
359                addAnnotation(annotation);
360            }
361            catch (RuntimeException ex) 
362            {
363                //Annotation processing may cause exceptions thrown by Javassist. 
364                //To provide backward compatibility we have to continue even though copying a particular annotation failed.
365                getLogger().error(String.format("Failed to copy annotation '%s' from '%s'", annotation.annotationType(), delegateClass.getName()));
366            }
367        }   
368    }
369    
370    public void copyMethodAnnotationsFromDelegate(Class serviceInterface, Class delegateClass)
371    {
372        lock.check();
373        
374        for(MethodSignature sig: addedSignatures)
375        {   
376            if(getMethod(sig, serviceInterface) == null)
377                continue;
378            
379            Method method = getMethod(sig, delegateClass);
380            
381            assert method != null;
382            
383            CtMethod ctMethod = getCtMethod(sig);
384            
385            Annotation[] annotations = method.getAnnotations();
386            
387            for (Annotation annotation : annotations)
388            {   
389                try
390                {
391                    addMethodAnnotation(ctMethod, annotation);   
392                }
393                catch (RuntimeException ex) 
394                {
395                    //Annotation processing may cause exceptions thrown by Javassist. 
396                    //To provide backward compatibility we have to continue even though copying a particular annotation failed.
397                    getLogger().error(String.format("Failed to copy annotation '%s' from method '%s' of class '%s'", 
398                            annotation.annotationType(), method.getName(), delegateClass.getName()));
399                }
400            }
401            
402            try
403            {
404                addMethodParameterAnnotation(ctMethod, method.getParameterAnnotations());
405            }
406            catch (RuntimeException ex) 
407            {
408                //Annotation processing may cause exceptions thrown by Javassist. 
409                //To provide backward compatibility we have to continue even though copying a particular annotation failed.
410                getLogger().error(String.format("Failed to copy parameter annotations from method '%s' of class '%s'", 
411                                method.getName(), delegateClass.getName()));
412            }
413        }
414    }
415    
416    private CtMethod getCtMethod(MethodSignature sig)
417    {
418        try
419        {
420            return getCtClass().getDeclaredMethod(sig.getName(), toCtClasses(sig.getParameterTypes()));
421        }
422        catch (NotFoundException e)
423        {
424            throw new RuntimeException(e);
425        }
426    }
427    
428    private Method getMethod(MethodSignature sig, Class clazz)
429    {
430        try
431        {
432            return clazz.getMethod(sig.getName(), sig.getParameterTypes());
433        }
434        catch (Exception e)
435        {
436            return null;
437        }
438    }
439
440    private void addAnnotation(Annotation annotation)
441    {
442        
443        final ClassFile classFile = getClassFile();
444        
445        AnnotationsAttribute attribute = (AnnotationsAttribute) classFile.getAttribute(AnnotationsAttribute.visibleTag);
446        
447        if (attribute == null)
448        {
449            attribute = new AnnotationsAttribute(getConstPool(), AnnotationsAttribute.visibleTag);
450        }
451        
452        final javassist.bytecode.annotation.Annotation copy = toJavassistAnnotation(annotation);
453        
454        
455        attribute.addAnnotation(copy);
456        
457        classFile.addAttribute(attribute);
458        
459    }
460    
461    private void addMethodAnnotation(final CtMethod ctMethod, final Annotation annotation) {
462
463        MethodInfo methodInfo = ctMethod.getMethodInfo();
464
465        AnnotationsAttribute attribute = (AnnotationsAttribute) methodInfo
466            .getAttribute(AnnotationsAttribute.visibleTag);
467
468        if (attribute == null) {
469            attribute = new AnnotationsAttribute(getConstPool(), AnnotationsAttribute.visibleTag);
470        }
471
472        final javassist.bytecode.annotation.Annotation copy = toJavassistAnnotation(annotation);
473
474        attribute.addAnnotation(copy);
475
476        methodInfo.addAttribute(attribute);
477
478    }
479
480    private void addMethodParameterAnnotation(final CtMethod ctMethod, final Annotation[][] parameterAnnotations) {
481
482        MethodInfo methodInfo = ctMethod.getMethodInfo();
483
484        ParameterAnnotationsAttribute attribute = (ParameterAnnotationsAttribute) methodInfo
485            .getAttribute(ParameterAnnotationsAttribute.visibleTag);
486
487        if (attribute == null) {
488            attribute = new ParameterAnnotationsAttribute(getConstPool(), ParameterAnnotationsAttribute.visibleTag);
489        }
490        
491        List<javassist.bytecode.annotation.Annotation[]> result = CollectionFactory.newList();
492        
493        for (Annotation[] next : parameterAnnotations) 
494        {
495                List<javassist.bytecode.annotation.Annotation> list = CollectionFactory.newList();
496                
497                        for (Annotation annotation : next) 
498                        {
499                        final javassist.bytecode.annotation.Annotation copy = toJavassistAnnotation(annotation);
500                        
501                        list.add(copy);
502                        }
503                        
504                        result.add(list.toArray(new javassist.bytecode.annotation.Annotation[]{}));
505                }
506        
507        javassist.bytecode.annotation.Annotation[][] annotations = result.toArray(new javassist.bytecode.annotation.Annotation[][]{});
508        
509        attribute.setAnnotations(annotations);
510        
511        methodInfo.addAttribute(attribute);
512    }
513    
514    private ClassFile getClassFile()
515    {
516        return getCtClass().getClassFile();
517    }
518    
519    private ConstPool getConstPool() 
520    {   
521        return getClassFile().getConstPool();
522    }
523    
524    private javassist.bytecode.annotation.Annotation toJavassistAnnotation(final Annotation source)
525    {
526
527        final Class<? extends Annotation> annotationType = source.annotationType();
528
529        final ConstPool constPool = getConstPool();
530
531        final javassist.bytecode.annotation.Annotation copy = new javassist.bytecode.annotation.Annotation(
532                annotationType.getName(), constPool);
533
534        final Method[] methods = annotationType.getDeclaredMethods();
535
536        for (final Method method : methods)
537        {
538            try
539            {
540                CtClass ctType = toCtClass(method.getReturnType());
541                
542                final MemberValue memberValue = javassist.bytecode.annotation.Annotation.createMemberValue(constPool, ctType);
543                final Object value = method.invoke(source);
544
545                memberValue.accept(new AnnotationMemberValueVisitor(constPool, getSource(), value));
546
547                copy.addMemberValue(method.getName(), memberValue);
548            }
549            catch (final Exception e)
550            {
551                throw new RuntimeException(e);
552            }
553        }
554
555        return copy;
556    }
557}