AOP Challenge: can it do this ?

[Gavin Bong]

Let's revisit the logging aspect. I need to add logging information
between two statements inside a method.
e.g.

1  public void doSomething(){
2    int i = 0;
3
4    i++;
5    i = filter1();
6    i = filter2();
7
8  }

I want to log the value of i after statement 4 and also after statement 5. Can AOP (e.g. AspectJ) do this ?
Thanks
Gavin

[Lasse Koskela]

Based on the quick reference, I doubt that's possible. On the other hand, the example you mentioned is not really cross-cutting, is it?

[Michael Zalewski]

After line 5 is easy. Just log the return from filter1().
After line 4 is hard only because i is not a true object. If i was an Integer object, or if you incremented i with its own method.

[Lasse Koskela]

I'm finally starting to realize the power of the pointcut constructs...

[Ramnivas Laddad]

Gavin,
AspectJ does not expose join point corresponding to local variables inside a method (had "i" been a instance or class variable, you would be able to advice modifications to it).
As Michael points out, you could log the return values of calls to filter1() and filter2(). I would, however, suggest not using AspectJ for such purpose. Such logging isn�t really a crosscutting concern and therefore AOP won�t be the right tool for this job.
-Ramnivas