Re: [aspectj-users] Weaving into Java System Libs

[Nikolas Nehmer <nnehmer@xxxxxxxxxxxxxxxxxxxx>]

Hi,

1st problem solved. There was a little error in the pointcut! Sorry for 
that.

But there still is an open question. Why is the thisJoinPoint.getTarget 
in the following example always null? And yes, I double checked...it's 
not only the toString() method that delivers null results ;-)

pointcut init() : call(new()) && !within(TestAspect) && !within(setup..*);
after(): init() {
   System.out.println(thisJoinPoint.getTarget());
}
     
Cheers,
Nikolas

Nikolas Nehmer schrieb:
> Hi,
>
> I'm wondering if it is possible to monitor every constructor call in 
> my application e.g. including calls to java.lang.*. In my 
> understanding, this would only imply weaving code into "my" 
> application and not into java system libs.
>
> But if I use something like:
> pointcut init() : call(new())...;
> constructor calls within myApp are aspectized but constructor calls to 
> system libs are not. I understand that an initialization advice only 
> works in myApp but using call-advice should also work for system lib 
> calls? Am I wrong?
>
> Best Nikolas
>
> Alex Villazon schrieb:
> > Hi,
> >   In fact ajc does not restrict weaving into the class library, but 
> > the resulting code may break the VM bootstrapping or crash the VM...
> >
> > For LTW, you could implement your own weaving agent using the 
> > WeavingAdaptor, and use
> >
> >  bcelWorld.performExtraConfiguration("weaveJavaPackages=true,weaveJavaxPackages=true"); 
> >
> >
> > However, this solution does not apply if you need to weave classes 
> > loaded during VM bootstrapping.... and before the agent starts 
> > instrumentation.
> >
> > Be aware that you could easily have problems of infinite recursions 
> > if your advices use woven classes of the Java class library.
> >
> > These problems are discussed in pdf 
> > <http://www.inf.unisi.ch/projects/ferrari/Publications_files/pppj08.pdf>
> >
> > Hope that helps.
> >
> > Cheers,
> >
> > Alex
> >
> >
> > On Jul 27, 2009, at 11:58 AM, Nikolas Nehmer wrote:
> >
> > > Even LTW seems to stop at the boundary to the java system libs. How
> > > exactly did you solve that problem?
> > >
> > > cheers Nikolas
> > >
> > > FraGMenT schrieb:
> > > > As far as I know you are looking for the Load-Time Weaving. I had more
> > > > or less the same problem and solved it with LTW. I'm afraid you cannot
> > > > weave system libraries at compile time.
> > > >
> > > > Hope this helped you.
> > > >
> > > > 2009/7/22 Nikolas Nehmer <nnehmer@xxxxxxxxxxxxxxxxxxxx 
> > > > <mailto:nnehmer@xxxxxxxxxxxxxxxxxxxx>
> > > > <mailto:nnehmer@xxxxxxxxxxxxxxxxxxxx>>
> > > >
> > > >    Hi there,
> > > >
> > > >    I'm new to AOP and AspectJ in particular. Today I started
> > > >    exploring some simple HelloWorld style example aspects. As far as
> > > >    I can tell, everything seems to work smoothly. But currently I
> > > >    have one issue. Is there any chance of weaving bytecode into the
> > > >    java systems libraries (e.g. java.lang.System,…) by “exploiting”
> > > >    AspectJ? I’m trying to circumvent writing my own bytecode
> > > >    instrumentation component. Any ideas?
> > > >
> > > >    Best regards,
> > > >
> > > >    Nick
> > > >
> > > >    _______________________________________________
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> > > >    aspectj-users@xxxxxxxxxxx <mailto:aspectj-users@xxxxxxxxxxx>
> > > >    https://dev.eclipse.org/mailman/listinfo/aspectj-users
> > > >
> > > >
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> > > >
> > > >
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> > >
> > > --
> > > Dipl.-Inf. Nikolas Nehmer,
> > > Dept. of Computer Science. University of Kaiserslautern
> > > P.O. Box 3049, 67653 Kaiserslautern, Germany.
> > > room 36/308, phone: +49 (0) 631 - 205 2644, fax: +49 (0) 631 - 205 3299
> > > mail: nnehmer@xxxxxxxxxxxxxxxxxxxx 
> > > <mailto:nnehmer@xxxxxxxxxxxxxxxxxxxx>
> > >
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> >   


--
Dipl.-Inf. Nikolas Nehmer,
Dept. of Computer Science. University of Kaiserslautern 
P.O. Box 3049, 67653 Kaiserslautern, Germany.
room 36/308, phone: +49 (0) 631 - 205 2644, fax: +49 (0) 631 - 205 3299
mail: nnehmer@xxxxxxxxxxxxxxxxxxxx