Re: [aspectj-users] accessing members of this in intertype declarations

[Wes Isberg <wes@xxxxxxxxxxxxxx>]

The Programming Guide, Semantics appendix, section
"Inter-type member declarations" says:

  Any occurrence of the identifier this in the body of an
  inter-type constructor or method declaration, or in the
  initializer of an inter-type field declaration, refers
  to the OnType object rather than to the aspect type;
  it is an error to access this in such a position from
  a static inter-type member declaration.

http://dev.eclipse.org/viewcvs/indextech.cgi/~checkout~/aspectj-home/doc/progguide/semantics-declare.html#d0e6005

So use "this" in non-static contexts to refer to the type being
declared on.

  aspect A {
     public void C.foo() {
         this.bar(); // for C.bar()
     }
  }

You can't refer to either the aspect type or
to subtypes of the type declared on, so in your case you
cannot refer to a member of type C that implements
interface I in the body of a method declared on I.

You can declare the method on C directly, or surface the
instance of C with this(), target() or  args() and then use
that, if the member is accessible.

In any case, if C is to be affected by

  declare parents : C implements I

then C has to be in the code the compiler controls, as a
source file or in the -injars.

And if C is affected (implements I), then any subclass
of C is also affected (will implement I).  This is just
straight Java.

Wes

Lendvai Attila wrote:
> hi!
>
> if i define an aspect with inter-type member declarations, is there any
> way to access the this pointer of the type it's applied to.
>
> i have a class C {}. i apply aspect A {} to a few subclasses of C. in
> the body of a method in A i would like to access the C instance...
>
> class C
> {
> 	void bar()
> 	{
> 	}
> }
>
> class D extends C {}
> class E extends C {}
>
> aspect A
> {
> 	private interface IA {};
>
> 	declare parents (C || D) implements IA;
>
> 	void IA.foo()
> 	{
> 		?.bar();
> 	}
> }
>
> C is in a library without an interface and i would not like to use
> injar, but E should not get the functinality in A anyways.
>
> or should i do this in a different way?
>
> thanks,
>
> - 101
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