Hi Simone,
Can you please tell me what's wrong with this pointcut. I want all the
methods which is in a type annotated with @Observable and the method itself
annotated with @Event
@Observable
public class O1 {
@Event(value = {"EVENT1","EVENT2"})
public void method1(String str) {
}
}
package com.foo.aspect;
import com.foo.annotation.*;
public aspect EventDispatcherAspect {
pointcut eventMethods(Object obj,Object iparam) :
within(@Observable com.*)
&& execution(* *.*(..))
&& @annotation(Event)
&& args(iparam)
&& target(obj);
after(Object obj,Object iparam) returning: eventMethods(obj,iparam)
{
System.out.println("thisJoinPoint:"+thisJoinPointStaticPart.toLongString());
System.out.println("thisJoinPointSig:"+thisJoinPointStaticPart.getSignature().toLongString());
//System.out.println("Events: "+e.value());
}
}
Regards,
Mohammad
--------------------------
On Wed, Apr 21, 2010 at 4:51 PM, Simone Gianni <[email protected]> wrote:
> Hi Mohammad,
> nope, unfortunately AspectJ is not able to declare fields "dynamically",
> moreover private fields injected by AspectJ have a number of limitations
> that are being solved (they have mangled names).
>
> What you can do however is :
> - Declare an interface WithObserverABC
> - Use an ITD to place a privare field on that interface
> - Inject that interface on all classes that have @Observable
> - Write the aspect that calls the observer method when an @Observable
> method is executed.
>
> public aspect InjectObserverABC {
> public interface WithObserverABC {}
>
> // this could be private, except for name mangling, depends on AspectJ
> version
> public ObserverAbc WithObserverABC.abcObserver = new ObserverABCImpl();
>
> // you could narrow this
> declare parents : hasmethod(@Observable *(..)) implements
> WithObserverABC;
>
> before(WithObserverABC instance) : execution(@Observable *
> WithObserverABC+.*(..)) && this(instance) {
> instance.abcObserver.
> notifyObserver();
> }
> }
>
> I'm not sure about the syntax (I wrote it here in this email, and i need
> compiler support when writing pointcuts :) ), but you should get the idea.
> Eventually you can try to play with generics/abstract aspects to make it
> easier to inject new observers, but I cannot think of a way of doing this
> completely automatically (apart from using APT to parse classes with
> @Observer and generate dynamically aop.xml to instantiate concrete aspects
> ... but that's another story :) )
>
> Hope this helps,
> Simone
>
>
> 2010/4/20 Mohammad Norouzi <[email protected]>
>
> Hi Simone,
>>
>> >>if I understand correctly, when a method annotated with @Observable is
>> executed, you want to see if there are fields in that class with an instance
>> of an observer, and call a method on the observer.<<
>> Actually, when a method is annotated with @Observable (before executing
>> and at the time of compiling codes) I want to add (not see) those interfaces
>> that annotated with @Observer, as private fields in the observable and I
>> want to add them because both observer and observable are EJB session beans
>> so the application server will take the burden of instantiating those
>> observers using its injection technique
>>
>> What I need is something like this:
>> for(MyObserver o : observers){
>> declare a private field with a name in this instance of observable
>> class
>>
>> }
>>
>>
>> On Mon, Apr 19, 2010 at 2:22 PM, Simone Gianni <[email protected]>wrote:
>>
>>> Hi Mohammad,
>>> if I understand correctly, when a method annotated with @Observable is
>>> executed, you want to see if there are fields in that class with an instance
>>> of an observer, and call a method on the observer.
>>>
>>> You can use AspectJ to execute an advice before/after/around the
>>> execution of @Obervable methods, and use thisJoinPoint or the this()
>>> construct to find the instance of the method.
>>>
>>> Once you are there, you must use plain java reflection, and not AspectJ,
>>> to find fields in that class that contains an observer and invoke observer
>>> methods.
>>>
>>> To add @EJB annotation to all fields of type X where X is annotated with
>>> @Observer, you can use declare @class and write a type pattern that uses
>>> @Observer annotation. If @Observer annotation is placed on methods, you can
>>> use hasmethod() to find classes that has such methods, but beware cause
>>> hasmethod is somewhat experimental.
>>>
>>> Hope this helps,
>>> Simone
>>>
>>> 2010/4/19 is_maximum <[email protected]>
>>>
>>>
>>>> Thanks Simone, yes this is exactly what I want... but another question
>>>> is
>>>> that this is used using 'declare' and as far as I know declare is placed
>>>> in
>>>> aspect definition. How can I place it in a for-loop.
>>>>
>>>> Let me tell you the scenario may be I am in wrong way...
>>>>
>>>> I am trying to implement an observer pattern in EJB 3.0. I saw many
>>>> implementation using aspectJ but mine is a little different. The
>>>> difference
>>>> is that I want to inject observer into observable...
>>>>
>>>> Because session beans are managed object and in my case both observer
>>>> and
>>>> observable supposed to be session beans I want application server
>>>> injects
>>>> observer session beans in observable SB and then call observer methods
>>>>
>>>> These observer and observable methods will be annotated by the developer
>>>> with say @Observer and @Observable
>>>>
>>>> What I wanted was to look for @Observer methods and find their interface
>>>> and
>>>> put them like this:
>>>>
>>>> @EJB
>>>> private ObserverInterface1 observer1
>>>>
>>>> than each time the determined method is called I can call
>>>> observer1.notifyObserver() method
>>>>
>>>> Can you please help me on this?
>>>>
>>>>
>>>>
>>>>
>>>> Simone Gianni-2 wrote:
>>>> >
>>>> > Hi Mohammad,
>>>> > maybe you are loooking for the declare annotation statement?
>>>> >
>>>> http://www.eclipse.org/aspectj/doc/next/adk15notebook/annotations-declare.html
>>>> >
>>>> > Simone
>>>> >
>>>> >
>>>>
>>>>
>>>> -----
>>>> --
>>>> Regards
>>>>
>>>> Mohammad Norouzi
>>>>
>>>> Help each other to reach the future faster
>>>>
>>>> http://pixelshot.wordpress.com Pixelshot Photoblog
>>>>
>>>> http://brainable.blogspot.com Brainable Blog
>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://old.nabble.com/How-to-rewrite-a-class-with-AspectJ-tp28280867p28287273.html
>>>> Sent from the AspectJ - users mailing list archive at Nabble.com.
>>>>
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>>>
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