/**
* 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.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;
}
/**
* Given a bean-style interface, generate an instance of the interface by implementing getters and
* setters for each property. It will also add implementations to support the {@link
* SupportsRdfId} interface and generate simple, default equals, toString and hashCode methods.
*
* <p>If there are other non-bean style (getter and/or setter's for properties) methods on the
* interface, this will likely fail to generate the instance.
*
* @param theInterface the interface to build an instance of
* @param <T> the type of the interface
* @return New dynamically generated bytecode of a class that implements the given interface.
* @throws Exception if there is an error while generating the bytecode of the new class.
*/
public static synchronized <T> Class<T> generateInstanceClass(Class<T> theInterface)
throws Exception {
processedMethods.clear();
// TODO: can we use some sort of template language for this?
ClassPool aPool = ClassPool.getDefault();
aPool.appendClassPath(new LoaderClassPath(theInterface.getClassLoader()));
CtClass aInterface = aPool.get(theInterface.getName());
CtClass aSupportsRdfIdInterface = aPool.get(SupportsRdfId.class.getName());
CtClass aEmpireGeneratedInterface = aPool.get(EmpireGenerated.class.getName());
if (!Arrays.asList(aInterface.getInterfaces()).contains(aSupportsRdfIdInterface)
&& !SupportsRdfId.class.isAssignableFrom(theInterface)) {
throw new IllegalArgumentException(
"Class '"
+ theInterface.getName()
+ "' does not implement SupportsRdfId, cannot generate Empire suitable implementation.");
}
String aName = aInterface.getPackageName() + ".impl." + aInterface.getSimpleName() + "Impl";
CtClass aClass = null;
try {
// i had a good reason for doing this, but i dont remember what it is. when i do, i'll
// explain it here =)
aClass = aPool.get(aName);
return (Class<T>) BeanReflectUtil.loadClass(aName);
} catch (NotFoundException e) {
aClass =
aPool.makeClass(
aInterface.getPackageName() + ".impl." + aInterface.getSimpleName() + "Impl");
} catch (ClassNotFoundException e) {
throw new Exception("Previously created class cannot be loaded.", e);
}
if (aClass.isFrozen()) {
aClass.defrost();
}
if (aInterface.isInterface()) {
aClass.addInterface(aInterface);
} else {
aClass.setSuperclass(aInterface);
}
aClass.addInterface(aSupportsRdfIdInterface);
aClass.addInterface(aEmpireGeneratedInterface);
CtField aInterfaceField =
new CtField(aPool.get(Class.class.getName()), "mInterfaceClass", aClass);
aClass.addField(
aInterfaceField, CtField.Initializer.byExpr(theInterface.getName() + ".class;"));
CtField aAllTriplesField = new CtField(aPool.get(Graph.class.getName()), "mAllTriples", aClass);
aClass.addField(
aAllTriplesField, CtField.Initializer.byExpr("new com.clarkparsia.openrdf.ExtGraph();"));
CtField aInstanceTriplesField =
new CtField(aPool.get(Graph.class.getName()), "mInstanceTriples", aClass);
aClass.addField(
aInstanceTriplesField,
CtField.Initializer.byExpr("new com.clarkparsia.openrdf.ExtGraph();"));
aClass.addConstructor(CtNewConstructor.defaultConstructor(aClass));
generateMethods(theInterface, aPool, aClass);
generateMethodsForSuperInterfaces(theInterface, aPool, aClass);
CtField aIdField = new CtField(aPool.get(SupportsRdfId.class.getName()), "supportsId", aClass);
aClass.addField(
aIdField,
CtField.Initializer.byExpr("new com.clarkparsia.empire.annotation.SupportsRdfIdImpl();"));
if (!hasMethod(aClass, "getRdfId")) {
aClass.addMethod(
CtNewMethod.make(
"public com.clarkparsia.empire.SupportsRdfId.RdfKey getRdfId() { return supportsId.getRdfId(); } ",
aClass));
}
if (!hasMethod(aClass, "setRdfId")) {
aClass.addMethod(
CtNewMethod.make(
"public void setRdfId(com.clarkparsia.empire.SupportsRdfId.RdfKey theURI) { supportsId.setRdfId(theURI); } ",
aClass));
}
if (!hasMethod(aClass, "getAllTriples")) {
aClass.addMethod(
CtNewMethod.make(
"public org.openrdf.model.Graph getAllTriples() { return mAllTriples; } ", aClass));
}
if (!hasMethod(aClass, "setAllTriples")) {
aClass.addMethod(
CtNewMethod.make(
"public void setAllTriples(org.openrdf.model.Graph theGraph) { mAllTriples = theGraph; } ",
aClass));
}
if (!hasMethod(aClass, "getInstanceTriples")) {
aClass.addMethod(
CtNewMethod.make(
"public org.openrdf.model.Graph getInstanceTriples() { return mInstanceTriples; } ",
aClass));
}
if (!hasMethod(aClass, "setInstanceTriples")) {
aClass.addMethod(
CtNewMethod.make(
"public void setInstanceTriples(org.openrdf.model.Graph theGraph) { mInstanceTriples = theGraph; } ",
aClass));
}
String equalsMethodBody =
"public boolean equals(Object theObj) {\n"
+ " if (theObj == this) return true;\n"
+ " if (!(theObj instanceof com.clarkparsia.empire.SupportsRdfId)) return false;\n"
+ " if (!(mInterfaceClass.isAssignableFrom(theObj.getClass()))) return false;\n"
+ " return getRdfId().equals( ((com.clarkparsia.empire.SupportsRdfId) theObj).getRdfId()) && super.equals(theObj);\n"
+ "}\n";
aClass.addMethod(CtNewMethod.make(equalsMethodBody, aClass));
if (theInterface.isInterface()) {
aClass.addMethod(
CtNewMethod.make(
"public String toString() { return getRdfId() != null ? getRdfId().toString() : super.toString(); } ",
aClass));
aClass.addMethod(
CtNewMethod.make(
"public int hashCode() { return getRdfId() != null ? getRdfId().hashCode() : 0; } ",
aClass));
}
aClass.freeze();
Class<T> aResult = (Class<T>) aClass.toClass();
try {
// make sure this is a valid class, that is, we can create instances of it!
aResult.newInstance();
} catch (Exception ex) {
// TODO: log this?
throw ex;
}
return aResult;
}