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RE: [aspectj-users] Overriding pointcuts
|
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
>
> That’s not how I read the programmer’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
>
>
>
>
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