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AW: Possible Bug: [aspectj-users] Overriding pointcuts

Hi Bo,

 

Thanks for your suggestion. It works very well.

 

Regards

 

Sven

 

-----Ursprüngliche Nachricht-----
Von: aspectj-users-bounces@xxxxxxxxxxx [mailt
o:aspectj-users-bounces@xxxxxxxxxxx] Im Auftrag von Bo Yi
Gesendet: Freitag, 21. Oktober 2005 15:19
An:
aspectj-users@xxxxxxxxxxx
Cc: aspectj-users-bounces@xxxxxxxxxxx;
aspectj-users@xxxxxxxxxxx; 'Thiago Bartolomei'
Betreff: Re: Possible Bug: [aspectj-users] Overriding pointcuts

 


Hi,

I believe this is a problem with target() and this().

target() needs compile time type checking to make sure all types are consistent. Thus it will fail when checks
pointcut log(Fifo fifo) : Logging.log(fifo) || execution(* Fifo.Get(..)) && target(fifo);

On the other hand, it is dynamically bound to the target object instance. Thus,        
pointcut log(Fifo fifo) : Logging.log(fifo) || execution(* Fifo.Get(..)); will fail for no target binding to the second part.

I think this is a bug but not sure whether it is fixable (without modify the language spec).

A work around is to use target() in advices rather than in pointcuts.

Bo
----------------------------------------------------------
 Dr. Bo Yi
 WebSphere Development & Testing
 IBM Toronto Lab
 A2-713/Q2Z/8200/MKM
 8200 Warden Ave. Markham ONT. L6G 1C7
 Phone: 905-413-4819
 Tie Line: 969-4819
 E-Mail: boyi@xxxxxxxxxx


"Sven Apel" <apel@xxxxxxxxxxxxxxxxxxxxxxx>
Sent by: aspectj-users-bounces@xxxxxxxxxxx

10/21/2005 08:17 AM

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Possible Bug: [aspectj-users] Overriding pointcuts

 

 

 




Hi,
 
Now that I have installed aspectj1.5 your proposal compiles (I had aspectj1.2 installed before), however, but throws the same exception. I think this could be a bug. Has anybody an idea?
 
Unfortunately, simply combining both pointcuts in one aspect is not what I want.
 
Regards,
 
Sven
 
-----Ursprüngliche Nachricht-----
Von:
Thiago Bartolomei [mailto:thiagobart@xxxxxxxxx]
Gesendet:
Freitag, 21. Oktober 2005 13:56
An:
Sven Apel
Betreff:
Re: [aspectj-users] Overriding pointcuts

 
Hi,

strange. Which version of ajc are you using? Because I don't get any errors on compilation. I am using version 1.5 (from the last ajdt version).
Altough I don't get any compilation error, when I run the example, I get the following exception:

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

I know it does not answer your question, but you could use this pointcut to solve your particular problem:

( execution(* Fifo.Put(..)) || execution(* Fifo.Get(..)) ) && target(fifo);

I am not sure, but it looks like a bug to me (in the compiler or weaver).

Regards,
Thiago



On 10/21/05, Sven Apel <apel@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

Hi Thiago,

 

Unfortunately this does not work. Using "target(fifo)" I get the following error message:

 

ajc *.java

/home/apel/iti_home/Entwicklung/Eigene Projekte/AOP/Semaphor/Fifo.java:25 [error] Cannot use target() to match at this location and bind a formal to type 'Fifo' - the formal is already bound to type 'Fifo'.  The secondary source location points to the problematic target().

public void Put(Value val)

^^^^^^^^^^^^^^^^^^^^^^^^^

        see also: /home/apel/iti_home/Entwicklung/Eigene Projekte/AOP/Semaphor/ExtLogging.java:3

/home/apel/iti_home/Entwicklung/Eigene Projekte/AOP/Semaphor/Fifo.java:30 [error] Cannot use target() to match at this location and bind a formal to type 'Fifo' - the formal is already bound to type 'Fifo'.  The secondary source location points to the problematic target().

public Value Get() throws NoSuchElementException

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

        see also: /home/apel/iti_home/Entwicklung/Eigene Projekte/AOP/Semaphor/ExtLogging.java:3

 

2 errors

 

 

For clarification, I send you the Fifo class:

 

public class Fifo

{

            public void Put(Value val)

            {

                        m_buf.add(val);

            }

           

            public Value Get() throws NoSuchElementException

            {

                        Value result;

                        try

                        {

                                   result = (Value)m_buf.firstElement();      

                        }

                        catch(NoSuchElementException exception)

                        {

                                   throw exception;

                        }

                        m_buf.remove(result);

                        return result;

            }

           

            public static void main(String[] args)

            {

                        Fifo fifo = new Fifo(256);

                        fifo.Put(new Value(23));

                        fifo.Put(new Value(32));

           

                        System.out.println(fifo.Get().GetInt());

            }

}

 

regards

 

Sven

 

-----Ursprüngliche Nachricht-----
Von:
aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-bounces@xxxxxxxxxxx] Im Auftrag von Thiago Bartolomei
Gesendet:
Freitag, 21. Oktober 2005 12:55
An:
aspectj-users@xxxxxxxxxxx
Betreff:
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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