pointcut all method calls on an object that implements an interface [message #591968] |
Wed, 25 January 2006 15:07 |
Tom Coupland Messages: 14 Registered: July 2009 |
Junior Member |
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Hi everybody,
Been toying with this idea for a day or so and hoping someone will be able
to come up with a better solution than i have!
I want to match on any method calls on an object that implements an
interface, not only the methods defined by that interface, but all other
method calls on the obj as well. Heres some class that should make it abit
clearer.
public class TheSubject implements TheInterface{
public void interfaceDeclared() {}
public void classDeclared(){}
public static void main(String[] args){
TheSubject sub = new TheSubject();
System.out.println("Calling subjects implementation of interface");
sub.interfaceDeclared();
System.out.println("\nCalling subjects own method");
sub.classDeclared();
}
}
public interface TheInterface {
public void interfaceDeclared();
}
An now for the aspect
public aspect TheAspect {
pointcut interfaceMethod () : execution(void TheInterface.* ());
void around() : interfaceMethod(){
System.out.println("Interface joinpoint triggered");
}
pointcut classMethod(): execution (void TheSubject.* ());
void around() : classMethod(){
System.out.println("Class joinpoint triggered");
}
/*//This results in conditional advice around almost every method call
and does'nt match on the TheSubject calls....
pointcut anyMethod() : execution(void * ()) &&
if(implementsInter(TheInterface.class, thisJoinPoint.getThis()));
before() : anyMethod(){
System.out.println("Any Method aspect triggered");
}
private static boolean implementsInter(Class inter, Object obj){
return inter.isInstance(obj);
}*/
//This works but results in conditional advice around almost every method
called!
pointcut anyMethod() : target(TheInterface) && call(void * ( .. ));
before() : anyMethod(){
System.out.println("Any Method joinpoint triggered");
}
/*//Does'nt work and results in many conditional advice markers
pointcut anyMethod() :execution(void * ( .. )) && this(TheInterface);
before() : anyMethod(){
System.out.println("Any Method aspect triggered");
}*/
}
The output im looking for
Calling subjects implementation of interface
Any Method joinpoint triggered
Interface joinpoint triggered
Calling subjects own method
Any Method joinpoint triggered
Class joinpoint triggered
As you can see i have managed to make it work. However this results in a
huge number of 'conditional' advice markers, which is something i'd rather
not have. Planning to use this idea in a medium sized project and having
a conditional advice marker round every method is a little unacceptable
(Am i right in thinking that these conditionals with be tested at runtime
everytime a method is called?? thereby introducing abit of a slow dwn?).
So what im really looking for is a technique of matching all calls to on
object that implements a given interface at compile time.
Look forward to your ideas!
Tom
p.s. if anyones got the time i wld'nt mind hearing a little abit about why
the other commented pointcuts don't work as well.....
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