Re: [aspectj-users] Inner classes query

["neil loughran" <n.loughran@xxxxxxxxxxxxxxx>]

Thanks Wes,  I guess I'd better stick to convention then! ;-)

I was wondering why my pointcuts were not working and it was  surprise to
see the trace but I guess thats another powerful part of AspectJ, the
ability to view the currently executing joinpoints.  Really handy at times
especially when you're not 100% sure how to write the correct syntax.

----- Original Message ----- 
From: "Wes Isberg" <wes@xxxxxxxxxxxxxx>
To: <aspectj-users@xxxxxxxxxxx>
Sent: Monday, October 06, 2003 7:10 PM
Subject: Re: [aspectj-users] Inner classes query


> Isn't that just the convention for Java inner classes,
> to supply the enclosing instance as the first parameter?
>
> e.g., for
>    class Outer {
>      class Inner{}
>    }
>
> the bytecode invocation would be to
>
>    Outer$Inner."<init>":(LOuter;)V
>
> (There must be a VM/JLS entry on point.)
>
> Note that this affects the join point signature and pointcut
> matching.  For example, this pointcut would not match:
>
>     call(Outer.Inner.new())
>
> but this would:
>
>     call(Outer.Inner.new(Outer))
>
> and if you print thisJoinPoint.getSignature(), it will
> show a parameter of type Outer.
>
> So: I think this is a case where AspectJ is doing the
> right thing in following the Java model, but that most
> Java developers don't realize there is an implicit
> argument for the enclosing instance, unless they have
> constructed instances of inner classes like this:
>
>    Outer o = new Outer();
>    Inner i = o.new Inner();
>
> I don't think we can or should omit the parameter,
> and emitting warnings would be hard.  But we can
> document this, probably along with some of the
> other gotcha's with nested classes.
>
> Other solutions?
>
> Wes
>
> neil loughran wrote:
> > Why does the trace for the aspect Foo below show  execution(Foo.Bar(Foo,
String)) when I was expecting Foo.Bar(String) ?
> >
> > When I move the inner class outside the aspect, I get the expected
behaviour execution(Bar(String))
> >
> > I'm sure I'm missing something :-)
> >
> > Thanks
> > Neil
> >
> >
> > aspect Foo
> >  {
> >
> >  after(String s) : args(s) && call(public void myMethod(String))
> >   {
> >   process(s);
> >   }
> >
> >
> >  public void process(String s)
> >    {
> >    Bar p = new Bar(s); // trace on this line of code
> >    }
> >
> >   class Bar
> >      {
> >      public Bar(String s)
> >       {
> >
> >       }
> >      }
> >   }
>
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