Re: [abc-users] Tracematch and "if(thisJoinPoint.getThis() != aParticularObject)"

On Wed, Apr 23, 2008 at 5:53 PM, Eric Bodden <eric.bodden_at_mail.mcgill.ca> wrote:
> Hi all.
>
>
> Just to add to what Pavel said:
>
> > I'm slightly confused about your choice of pattern. Why do you have the
> > fragment "exitWriteAnother*"? Since that symbol binds none of the tracematch
> > variables, and you intend it to match exit events that bind something other
> > than w1 and w2, I believe the correct way of achieving this is simply having
> > the pattern "enterWrite1 enterWrite2", which will allow zero or more objects
> > distinct from w1 and w2 to exit in between the two events...
>
> A agree with Pavel that your pattern is incorrect. In fact I once
> wrote a very similar tracematch to detect lock order reversal. The
> general workaround that one can take is to simply compare variables in
> the tracematch body. This is not quite as efficient as a "distinct"
> annotation would be but it should give you correct results. In your
> example:
>
>
> tracematch(Writer w1, Writer w2)
> {
>
> sym enterWrite1 after:
> call(* Database.enterWrite()) && this(w1);
>
>
> sym enterWrite2 after:
> call(* Database.enterWrite()) && this(w2);
>
>
> sym exitWrite1 after:
> call (* Database.exitWrite()) && this(w1);
>
>
> sym exitWrite2 after:
> call (* Database.exitWrite()) && this(w2);
>
> enterWrite1 enterWrite2
> {
> if(w1!=w2) {
>
> System.out.println("Writers "+w1+" and "+w2+
> " have entered concurrently");
> }
> }
> }
>
> Eric
>
> --
> Eric Bodden
> Sable Research Group
> McGill University, Montréal, Canada
>

I agree with your answers. Even I think that exitWrite2 symbol is not
necessary.
Thank very much.

Paul Leger.
Received on Wed Apr 23 2008 - 23:14:11 BST