[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
AW: [aspectj-users] Overriding pointcuts

Hi Wes,

Back to my office I tried your solution but I got a runtime exception (the
same that I described in a previous mail):

Exception in thread "main" java.lang.VerifyError: (class: Fifo, method: Get
signature: ()LValue;) Unable to pop operand off an empty stack

Is this a bug or not?

Regards

Sven

> -----Ursprüngliche Nachricht-----
> Von: aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-
> bounces@xxxxxxxxxxx] Im Auftrag von Wes Isberg
> Gesendet: Samstag, 22. Oktober 2005 00:43
> An: aspectj-users@xxxxxxxxxxx
> Betreff: RE: [aspectj-users] Overriding pointcuts
> 
> > The problems arise when I have
> > pointcuts
> > that expect arguments, as in the fifo example.
> 
> For me your code works when fifo is bound in all legs of the pointcut:
> 
> ----
> aspect ExtLogging extends Logging {
>   pointcut log(Fifo fifo) : Logging.log(fifo) ||
>     (this(fifo) && execution(* Fifo.Get(..)));
> }
> ----
> 
> Wes
> 
> 
> 
> > ------------Original Message------------
> > From: apel@xxxxxxxxxxxxxxxxxxxxxxx
> > To: "Wes Isberg" <wes@xxxxxxxxxxxxxx>, rbodkin@xxxxxxxxxxxxxx, aspectj-
> users@xxxxxxxxxxx
> > Date: Fri, Oct-21-2005 1:34 PM
> > Subject: RE: [aspectj-users] Overriding pointcuts
> >
> > Hi Wes and Rod,
> >
> > I know that this example works. The problems arise when I have
> > pointcuts
> > that expect arguments, as in the fifo example.
> >
> > By the way, in a recent paper we propose the notion of aspect
> > refinement:
> > http://wwwiti.cs.uni-magdeburg.de/~apel/AOASIA2005.pdf
> > With aspect refinement it is possible to use the "super" keyword to
> > refer
> > to the parent pointcuts. In this way we can extend or constrain the set
> > of
> > join points using a subsequent subaspect. Unfortunately, this is
> > currently
> > implemented in FeatureC++/AspectC++ only:
> > http://wwwiti.cs.uni-magdeburg.de/iti_db/forschung/fop/featurec/
> > Currently, we work on a version for AspectJ, using the abc. In fact, I
> > ask
> > these questions to get insight in the semantics of AspectJ to implement
> > aspect refinement in AspectJ. In an upcoming report we explain more
> > details about our extension of AspectJ, including the things about
> > pointcuts (we plan to publish the report next week).
> >
> > best regards
> >
> > Sven
> >
> >
> > > Oh, good.  You're right that non-abstract pointcuts can also be
> > overridden
> > > and not just hidden (meaning the superaspect uses the subaspect
> > > declaration) - when the (implicit) reference is not a class.
> > > Note in this light that you can refer directly to the superaspect
> > > pointcut using a class/type reference:
> > >
> > > ----
> > > abstract aspect AA {
> > >     pointcut pc() : execution(void main(String[]));
> > >     before() : pc() { System.out.println("jp: " + thisJoinPoint); }
> > > }
> > > aspect A extends AA {
> > >     // AA.pc() refers to superaspect pointcut
> > >     pointcut pc() : AA.pc() || (withincode(void main(String[]))
> > >         && call(void PrintStream.println(String)));
> > > }
> > > ----
> > >
> > > It's too bad that using super as a reference is illegal:
> > >
> > > ----
> > >     // error
> > >     pointcut pc() : super.pc() || ...
> > > ----
> > >
> > > It's when the pointcut reference is a class/type that hiding
> > > comes into play, and can support a limited form of redeclaration
> > > for external (class-reference) clients, e.g., of a library:
> > >
> > >
> > http://eclipse.org/aspectj/sample-code.html#library-classPointcutLibrary
> > >
> > > I'll document this somewhere, as long as Andrew/Adrian/Erik, et al
> > > don't say it's accidental.
> > >
> > > Wes
> > >
> > >> ------------Original Message------------
> > >> From: "Ron Bodkin" <rbodkin@xxxxxxxxxxxxxx>
> > >> To: "'Wes Isberg'" <wes@xxxxxxxxxxxxxx>, aspectj-users@xxxxxxxxxxx
> > >> Date: Fri, Oct-21-2005 11:24 AM
> > >> Subject: RE: [aspectj-users] Overriding pointcuts
> > >>
> > >> Thatâ&#8364;&#8482;s not how I read the programmerâ&#8364;&#8482;s
> > guide. From
> > >>
> > http://www.eclipse.org/aspectj/doc/released/progguide/semantics-
> pointcuts.ht
> > >> ml
> > >>
> > >> "Pointcuts that are not final may be declared abstract, and defined
> > >> without
> > >> a body. Abstract pointcuts may only be declared within abstract
> > >> aspects.
> > >>   abstract aspect A {
> > >>       abstract pointcut publicCall(int i);
> > >>   }
> > >>
> > >> In such a case, an extending aspect may override the abstract
> > pointcut.
> > >>
> > >>   aspect B extends A {
> > >>       pointcut publicCall(int i): call(public Foo.m(int)) &&
> > args(i);
> > >>   }
> > >> For completeness, a pointcut with a declaration may be declared
> > final.
> > >>
> > >> Though named pointcut declarations appear somewhat like method
> > >> declarations,
> > >> and can be overridden in subaspects, they cannot be overloaded. It
> > is
> > >> an
> > >> error for two pointcuts to be named with the same name in the same
> > >> class or
> > >> aspect declaration. "
> > >>
> > >> Notice that pointcut declarations can be overridden in subaspects.
> > The
> > >> sentence does not limit them to abstract pointcuts.
> > >>
> > >> Moreover, the feature works as I read the description and I have
> > found
> > >> it
> > >> useful as in my earlier posting about how I used pointcut overriding
> > >> for the
> > >> glassbox inspector. Here is a simple xample:
> > >>
> > >> public abstract aspect Base {
> > >>     public pointcut methodExec();
> > >>     before() : methodExec() {
> > >> 	System.out.println("advised by "+this);
> > >>     }
> > >>
> > >>     public static void main(String args[]) {}
> > >> }
> > >>
> > >> aspect Derived1 extends Base {
> > >>     public pointcut methodExec() : execution(* main(..));
> > >> }
> > >>
> > >> aspect Derived2 extends Base {}
> > >>
> > >> C:\devel\scratch\override>ajc Base.aj
> > >>
> > >> C:\devel\scratch\override>java Base
> > >> advised by Derived1@12c1c0
> > >>
> > >>
> > >>
> > >>
> > >> ________________________________________
> > >> From: aspectj-users-bounces@xxxxxxxxxxx
> > >> [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of Wes Isberg
> > >> Sent: Friday, October 21, 2005 10:56 AM
> > >> To: aspectj-users@xxxxxxxxxxx
> > >> Subject: Re: [aspectj-users] Overriding pointcuts
> > >>
> > >> Also, Pointcuts are like static methods: they can be hidden but not
> > >> overridden.
> > >> And you cannot overload a pointcut name (e.g., with more or fewer
> > >> variables).
> > >>  
> > >> In this case the advice in the abstract aspect will run only on the
> > >> join
> > >> points picked out
> > >> by the pointcut in the abstract aspect.   the pointcut in the
> > subaspect
> > >> does
> > >> not override
> > >> but hides the superaspect pointcut of the same name (indeed, I
> > thought
> > >> we
> > >> had an
> > >> XLint warning for this.)
> > >>  
> > >> Normally the pointcut in the abstract aspect is itself abstract, for
> > >> just
> > >> this reason. 
> > >> Some people use the convention of another   pointcut titled
> > >> {name}_default to
> > >>
> > >> offer reusable pointcut for subaspects to consider.
> > >>  
> > >> Wes
> > >>  
> > >> ------------Original Message------------
> > >> From: Thiago Bartolomei <thiagobart@xxxxxxxxx>
> > >> To: aspectj-users@xxxxxxxxxxx
> > >> Date: Fri, Oct-21-2005 3:54 AM
> > >> Subject: Re: [aspectj-users] Overriding pointcuts
> > >> Hi,
> > >>
> > >> try to append target to your pointcut:
> > >>
> > >> pointcut log(Fifo fifo) : Logging.log(fifo) || execution(*
> > >> Fifo.Get(..)) &&
> > >> target(fifo);
> > >>
> > >> I think the problem is that the compiler needs to know what to do
> > with
> > >> your
> > >> fifo variable in all cases . Without the target, the second part of
> > the
> > >> "or"
> > >> would have no context exposure..
> > >>
> > >> []s
> > >> Thiago T. Bartolomei
> > >> On 10/21/05, Sven Apel <apel@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > >> Hi,
> > >>
> > >> I have a problem with overriding and reusing pointcuts. I want to
> > >> extend the
> > >> set of join points captured by the "log" pointcut in the aspect
> > >> "Logging":
> > >>
> > >> abstract public aspect Logging
> > >> {
> > >>                 pointcut log(Fifo fifo) : execution(* Fifo.Put(..))
> > &&
> > >> target(fifo);
> > >>
> > >>                 before(Fifo fifo) : log(fifo)
> > >>                 {
> > >>                                 System.out.println("---> Fifo method
> > >> called");
> > >>                 }
> > >> }
> > >>
> > >> For that I want to use a further aspect that inherits from
> > "Logging":
> > >>
> > >> public aspect ExtLogging extends Logging
> > >> {
> > >>                 pointcut log(Fifo fifo) : Logging.log(fifo) ||
> > >> execution(*
> > >> Fifo.Get(..));
> > >> }
> > >>
> > >> The above example does not work because ajc cannot bind "fifo"
> > >> (inconsistent
> > >> binding).
> > >>
> > >> The following example also does not work:
> > >>
> > >> public aspect ExtLogging extends Logging
> > >> {
> > >>                 pointcut log() : Logging.log(Fifo) || execution(*
> > >> Fifo.Get(..));
> > >> }
> > >>
> > >> This is because "ExtLogging.log" must have the same signature than
> > >> "Logging.log". Other variants that declare an argument list in
> > >> "ExtLogging.log" but do not pass "fifo" to "Logging.log" also do not
> > >> work
> > >>
> > >> Is there a possibility to override and reuse parent pointcuts that
> > >> expect
> > >> arguments? Without arguments the above example works!
> > >>
> > >> Thanks in advance
> > >>
> > >> Sven
> > >>
> > >> --
> > >> Dipl.-Inf. Sven Apel
> > >> Institute for Technical and Business Information Systems
> > >> Otto-von-Guericke-University
> > >> P.O. Box 4120, D-39016 Magdeburg, Germany
> > >> Phone: ++49 (391) 67-11899, Fax: ++49 (391) 67-12020
> > >> Room: 29/108
> > >> E-Mail: apel@xxxxxxxxxxxxxxxxxxxxxxx
> > >>
> > >>
> > >>
> > >>
> > >> _______________________________________________
> > >> 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
> > >>
> > >> _______________________________________________
> > >> 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
> > >
> >
> >
> > _______________________________________________
> > 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