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

[Andrew Eisenberg <andrew@xxxxxxxxxxxx>]

Have you tried using after returning advice?  That should be able to
capture the result of a 'new' call.

On Thu, Jul 30, 2009 at 4:20 AM, Nikolas
Nehmer<nnehmer@xxxxxxxxxxxxxxxxxxxx> wrote:
> 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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>>>>>
>>>>>
>>>>>
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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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>>>
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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
>
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