Re: [aspectj-users] Generated AjcClosure classes

[Simone Gianni <simoneg@xxxxxxxxxx>]

Hi Silviu,
the accept method gives you classes generated by AspectJ, I don't use it 
from an agent but from a classloader, and I can see closures being 
pushed using that method.

I don't know if it is accessible from an agent however.

Simone

Andrica Silviu wrote:
> Hi,
>
> On Dec 2, 2009, at 6:11 PM, Andy Clement wrote:
>
>   
> > Hi Silviu,
> >
> >     
> > > I am using Aj to perform runtime weaving. Afterwards, I'm saving the weaved
> > > class into a cache so as to avoid the instrumentation on subsequent runs.
> > >       
> > You know, I'm on the verge of creating such a thing in AspectJ
> > itself... I would be interested to here about your approach and how
> > you know when to invalidate the cache, and what are you using as the
> > cache key (some combination of the class itself hashed or something,
> > plus the combination of aspects defined at the time, hashed or
> > something?)
> >     
> Great to hear this. Or not :) because I'm currently writing a paper about these things.
> As a cache key I use a hash of the bytecode of the unaltered class. After I compute the hash, I weave aspects to the class and save the weaved class into the cache.
> On subsequent program executions, I recompute the hash and retrieve the weaved version. When the list of aspects I instrument classes with changes, I invalidate the cache.
> Thus, after changing the list of aspects, on subsequent runs, a new cache is rebuilt. One thing I'm considering is having caches for each sequence of applied aspects so as to not start from scratch if there is a common sub sequence between what I already cached and the new list of aspects.
>
>
>   
> > If AspectJ did this itself then the only user configuration would be a
> > place to keep these woven classes so that they can be retrieved later.
> > Do you have any specific requirements for the cache in your scenario?
> > (or does anyone else reading this have requirements on a cache like
> > this?)
> >     
> Well, I would like to be able to retrieve them. Nothing more. A predefined place would be best.
>   
> > > Now, my problem is that I use around advices that create additional
> > > Class$AjcClosure.
> > > Is there any way I can get handle of those classes? I must mention I am
> > > using a java agent that would normally be called whenever a new class is
> > > loaded, but it appears that the Closure classes somehow escape this.
> > >       
> > There currently isn't a way for you to get at them I don't think - but
> > there have been other requests to access them, or at least be made
> > aware of them.  This wasn't for a caching purpose but merely to avoid
> > clashes in the case where an attempt is made to define the same class
> > twice (https://bugs.eclipse.org/bugs/show_bug.cgi?id=287426).
> >     
> So what happens with the $AjcClosure classes? Isn't there a way I can get their bytecode? WeavingAdaptor has a method called "accept" that sounds to do just that. Also, the WeavingAdaptor constructor takes in a "GeneratedClassHandler". Is there a way I can get a hold of that handler from within "Aj"?
>
> Thanks a lot!
>
> Silviu
>   
> > Raise an enhancement request and I'll see what I can do.
> >
> > Andy
> > _______________________________________________
> > aspectj-users mailing list
> > aspectj-users@xxxxxxxxxxx
> > https://dev.eclipse.org/mailman/listinfo/aspectj-users
> >     
>
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@xxxxxxxxxxx
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>   


--
Simone Gianni            CEO Semeru s.r.l.           Apache Committer
http://www.simonegianni.it/