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Re: [aspectj-users] AspectJ and Eclipse RCP

Martin;

Thank you for your reply.  First off: I solved my issue, and AspectJ is now working as expected.  I'll walk through the issues.

Yes, I am using Equinox weaving.

Because Eclipse 4 RCP is OSGi based, OSGi issues and conventions must be addressed.

The first breakthrough I had was when I modified my pointcut to use execution instead of call.
i.e. pointcut mypointcut: execution(* *.myMethod());

That gave me aspect oriented behavior, though my before: aspect ran after the method.

I started looking more closely at the difference between execution and call, and I found that call gets weaved around the call, i.e. in the class / method one higher than the "target" method in the stack.

This means that I need to import the AspectJ bundles into the bundles which use the annotated methods, rather than the bundles which contain the annotated methods.

I then identified (through Internet research) a more subtle difference between execution and call: namely that call is weaved against the declared type, rather than the object type.  OSGi encourages programming to interfaces, so all code that uses a service from a different bundle declares the variable as the interface type.  When I tried to annotate the concrete implementation method, AspectJ didn't do anything.  It's necessary to annotate the interface's method declaration.

Retrieving the parameter from the custom annotation was a brief struggle as well, but that too fell to Internet research.

At the end of the day, it all works, and is quite slick.  Aspect Oriented Programming and AspectJ saved me from adding a layer, and passing around a session object, to an already complex system in order to apply authorization.

For anyone that is interested here is a basic version of the aspect I created:
Public aspect MyAspect
{
    pointcut mypointcut(MyAnnotation a): call(@MyAnnotation * *()) && @annotation(a);

    before(MyAnnotation a) throws MyException: mypointcut(a)
    {
        ...Aspect / advice code...
    }
}

I apologize for the length.

Thank you,

Dominic L. Hilsbos, MBA, CSDA 
Director - Information Technology 
Perform Air International Inc.


-----Original Message-----
From: aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of Martin Lippert
Sent: Thursday, February 18, 2016 5:57 AM
To: aspectj-users@xxxxxxxxxxx
Subject: Re: [aspectj-users] AspectJ and Eclipse RCP

Hey Dominic,

I guess you are using the Equinox weaving feature to weave your aspects into your RCP application, right?
Or is this limited to the scope of the bundle that the aspect lives in?

Maybe you can point me to a sample project that reproduces this behavior. Would love to take a more detailed look.

Cheers,
-Martin



> 
> Users;
> 
> I'm trying to use AspectJ with an Eclipse RCP program.  I want to use aspects for the normal things, i.e. authorization and logging.
> 
> My failures seem to fall into 2 broad types: crash and burn or don't do anything.
> 
> My first try aspect looks like this:
> 
> Public aspect MyAspect
> {
>    pointcut mypointcut: call(* *.myMethod());
> 
>    before(): mypointcut()
>    {
>        System.out.println("Hello Aspect oriented programming");
>    }
> }
> 
> I have extensive logging turned on, but am not really sure what I'm looking for.
> I get this: info register aspect <MyAspect> I also get this: info 
> weaving bundle '<my bundle>' with a bunch of stuff in between.
> I even get: debug weaving '<MyService>'
> 
> MyService registers with OSGi Declarative Services, and is injected into the RCP object, but when I call myMethod on MyService the aspect isn't called.
> 
> On the other hand, when I set up an aspect like this:
> Public aspect MyAspect
> {
>    pointcut mypointcut: call(* *.myMethod());
> 
>    before(): mypointcut()
>    {
>        System.out.println("Hello Aspect oriented programming");
>    }
> }
> 
> The RCP code freaks out, and doesn't run.
> 
> All the debug type output from AspectJ suggests that the AspectJ runtime is loaded and running.
> 
> BTW, where I eventually plan to go with this is to tie it to a Runtime Annotation, as follows:
> Public aspect MyAspect
> {
>    pointcut mypointcut: call(@MyAnnotation * *());
> 
>    before(): mypointcut()
>    {
>        System.out.println("Hello Aspect oriented programming");
>    }
> }
> 
> But this too generates no aspect output.
> 
> Any thoughts?
> 
> Thank you,
> 
> Dominic L. Hilsbos, MBA, CSDA
> Director - Information Technology
> Perform Air International Inc.
> 
> 
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