[aspectj-users] perthis and binding on super class.

[Adam Jenkins <ajenkins@xxxxxxxxxxxx>]

Title: perthis and binding on super class.

Hi All,

I'm having some issues solving a problem and was hoping someone could give some assistence.

I'm want to bind on the execution of a method in a super class and the perthis on the subclass.  For example, say we have the following:

        ______________________
        |       <<abstract>>      |
        |                         |
        |       Vehicle           |
        |-------------------------------------|
        |-------------------------------------|
        | + <final> stop():void   |
        |_____________________|
                           /\
                      /_ \
                        |
                        |
                        |
                            |
        _____________________
        |                       |
        |         Car           |
        |-----------------------------------|
        |-----------------------------------|
        |____________________|

I want to bind on the execution (not call as this is a packaged library) of say, the stop method.  However I want one aspect instance for each car object.  I would have thought it was something like this:

public aspect CarStopping perthis( execution ( Car.new() ) ){

        private boolean shouldNotify = false;

        public boolean getShouldNotify(){
                return shouldNotify;
        }

        public void setShouldNotify(boolean flag) {
                this.shouldNotify = flag;
        }

        pointcut stopCalled() : execution( void Vehicle.stop() );

        after() : stopCalled(){
                if(shouldNotify) System.out.println("Car stopped");
        }
}

And I could do something like:

        Car c = new Car();
        CarStopping stopping = CarStopping.aspectOf(c);
        stopping.setShouldNotify(true);
        car.stop();

But this solution doesn't work for me, which leads me to believe I'm doing something wrong.

Now, of course this is not the exact code I'm trying to get working as I have no real need to know anything about cars...it just demonstrated (I hope) what I'm trying to accompish.  Does anybody know of a good solution?

Cheers
Adam

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