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Re: [aspectj-users] target(object and al extending objects) 
See also

http://dev.eclipse.org/viewcvs/indextech.cgi/~checkout~/aspectj-home/doc/faq.html#q:adviseconstructors

Wes

Ron Bodkin wrote:


Ok, we've fixed your binding mechanism. One way of debugging what's going on is to have your advice print out thisJoinPoint.getTarget(); it will be null. Why? Because the target of a constructor call is always null. I don't think this is explicitly described in the programming guide, but Jim posted on a similar problem (see the thread Re: [aspectj-users] How to use "call pointcut", when using reflection).

One of the following approaches might work for you:
pointcut findConstructors(SuperClass superclass):
    	execution(SuperClass+.new(..)) && this(superclass);

Or:

after() returning (SuperClass obj): findConstructors () {
 	//do something with obj (type SuperClass, but I will cast it)
}

Besides, you undoubtedly want after returning advice, because if your constructor throws there will be no constructed object.

Ron Bodkin
Chief Technology Officer
New Aspects of Security
m: (415) 509-2895



------------Original Message-------------
From: MisterJ <misterj@xxxxxxxx>
To: aspectj-users@xxxxxxxxxxx
Date: Fri, Sep-5-2003 9:08 AM
Subject: Re: [aspectj-users] target(object and al extending objects)

Ron Bodkin wrote:


You're close:
pointcut findConstructors(SomeSuperClass superclass):
	call(SomeSuperClass+.new(..)) && target(superclass);


This doesn't seem to work. It compiles, bit this pointcut finds nothing.
I have one superclass "SuperClass" and a few classes extending from that superclass "ClassA", "ClassB", and so on. 

In my application I never construct a SuperClass, I only have

ClassA a = new ClassA ();
ClassB b = new ClassB ();
...
so I never have (for example)
SuperClass something = new ClassA ();

If I write this:

pointcut findConstructors () : call (SuperClass+.new(..));

after () : findConstructors () {
	//do something
}
Everything works fine (the after advices is executed for every new instance of ClassA, ClassB ...). But in that after advice I want to do something with the object just constructed (of type ClassA, ClassB, ...). 

Your suggestion is:

pointcut findConstructors(SuperClass superclass):
  	call(SuperClass+.new(..)) && target(superclass);

with this advice:

after (SuperClass obj) : findConstructors (obj) {
	//do something with obj (type SuperClass, but I will cast it)
}
That does compile, but it doesn't do anything. The after advice never gets executed. My IDE (eclipse) also indicates that that is the case. 

Am I missing something?
Jan

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