package com.googlecode.gwt.test.utils;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashSet;
import java.util.Set;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.NotFoundException;
import javassist.bytecode.AnnotationsAttribute;
import javassist.bytecode.annotation.AnnotationImpl;
import javassist.bytecode.annotation.StringMemberValue;
import com.googlecode.gwt.test.exceptions.GwtTestPatchException;
import com.googlecode.gwt.test.internal.GwtClassPool;
/**
* Utility class over the <code>javassist</code> API.
*
* @author Gael Lazzari
*
*/
public class JavassistUtils {
public static CtConstructor findConstructor(CtClass ctClass, Class<?>... argsClasses) {
Set<CtConstructor> set = new HashSet<CtConstructor>();
findConstructors(ctClass, set, argsClasses);
switch (set.size()) {
case 0:
return null;
case 1:
return set.iterator().next();
default:
throw new GwtTestPatchException("Multiple constructors (" + set.size() + ") in class "
+ ctClass.getName() + ", you have to set parameter types discriminators");
}
}
@SuppressWarnings("unchecked")
public static <T extends Annotation> javassist.bytecode.annotation.Annotation getAnnotation(
CtClass ctClass, Class<T> annotationClass) throws ClassNotFoundException {
T proxiedAnnot = (T) ctClass.getAnnotation(annotationClass);
if (proxiedAnnot == null) {
return null;
} else if (!Proxy.isProxyClass(proxiedAnnot.getClass())) {
return null;
}
AnnotationImpl impl = (AnnotationImpl) Proxy.getInvocationHandler(proxiedAnnot);
return impl.getAnnotation();
}
/**
* Retrieve the String value of an annotation which is not available at runtime.
*
* @param clazz The annotated class
* @param annotation The annotation which is not visible at runtime
* @param name The name of the String property of the annotation to retrieve
* @return The String value of the annotation or null if the annotation or its property is not
* present
*/
public static String getInvisibleAnnotationStringValue(Class<?> clazz,
Class<? extends Annotation> annotation, String name) {
CtClass ctClass = GwtClassPool.getCtClass(clazz);
ctClass.defrost();
AnnotationsAttribute attr = (AnnotationsAttribute) ctClass.getClassFile().getAttribute(
AnnotationsAttribute.visibleTag);
if (attr == null) {
attr = (AnnotationsAttribute) ctClass.getClassFile().getAttribute(
AnnotationsAttribute.invisibleTag);
}
if (attr == null) {
return null;
}
javassist.bytecode.annotation.Annotation an = attr.getAnnotation(annotation.getName());
ctClass.freeze();
return an != null ? ((StringMemberValue) an.getMemberValue(name)).getValue() : null;
}
/**
* Retrieve the String value of an annotation which is not available at runtime.
*
* @param method The annotated method
* @param annotation The annotation which is not visible at runtime
* @param name The name of the String property of the annotation to retrieve
* @return The String value of the annotation or null if the annotation or its property is not
* present
*/
public static String getInvisibleAnnotationStringValue(Method method,
Class<? extends Annotation> annotation, String name) {
CtClass ctClass = GwtClassPool.getCtClass(method.getDeclaringClass());
ctClass.defrost();
AnnotationsAttribute attr = (AnnotationsAttribute) ctClass.getClassFile().getMethod(
method.getName()).getAttribute(AnnotationsAttribute.visibleTag);
if (attr == null) {
attr = (AnnotationsAttribute) ctClass.getClassFile().getMethod(method.getName()).getAttribute(
AnnotationsAttribute.invisibleTag);
}
if (attr == null) {
return null;
}
javassist.bytecode.annotation.Annotation an = attr.getAnnotation(annotation.getName());
ctClass.freeze();
return an != null ? ((StringMemberValue) an.getMemberValue(name)).getValue() : null;
}
private static void findConstructors(CtClass ctClass, Set<CtConstructor> set,
Class<?>... argsClasses) {
try {
if (ctClass == null) {
return;
}
CtConstructor[] constructors = ctClass.getDeclaredConstructors();
if (constructors.length == 0) {
findConstructors(ctClass.getSuperclass(), set, argsClasses);
} else if (constructors.length == 1 && argsClasses.length == 0) {
set.add(constructors[0]);
} else {
for (CtConstructor c : constructors) {
if (c.getParameterTypes().length != argsClasses.length) {
continue;
}
boolean sameArgs = true;
for (int i = 0; i < argsClasses.length; i++) {
String requestedClassName = argsClasses[i].getName();
String currentClassName = c.getParameterTypes()[i].getName();
if (!requestedClassName.equals(currentClassName)) {
sameArgs = false;
}
}
if (sameArgs) {
set.add(c);
}
}
}
} catch (NotFoundException e) {
// should never happen
throw new GwtTestPatchException("Error while trying find a constructor in class '"
+ ctClass.getName() + "'", e);
}
}
private JavassistUtils() {
}
}