Re: [aspectj-users] Parameters

[Wes Isberg <wes@xxxxxxxxxxxxxx>]

  args(.., ClassX, ..)

should have worked in AspectJ 1.0, but, as Erik noted for 1.1,

  We did not implement the handling of more than one ..
  wildcard in args PCDs (rarely encountered in the wild)
  because we didn't have the time. This might be available
  in later releases if there is significant outcry

http://dev.eclipse.org/viewcvs/indextech.cgi/~checkout~/aspectj-home/doc/README-11.html#language

I'm not sure if a bug would qualify as a significant outcry,
but it would be a place others could chime in.

(Also, it's a doc bug that ".." in args(...) is not better documented.
I couldn't find it in either quick reference or the programming
guide semantics appendix; perhaps my search was bad.)

A workaround for now is to test the args directly, perhaps even
in an if pointcut:

aspect A {
   private static boolean hasArg(Class c, Object[] args) {
        for (int i = 0; i < args.length; i++) {
           if ((null != args[i]) &&
              c.isAssignableFrom(args[i].getClass())) {
              return true;
           }
        }
        return false;
   }
   before() : ... && if(hasArg(ClassX.class, thisJoinPoint.getArgs()) {
       ...
   }
}

Obviously, that won't pick out a null ClassX arg, and it
can be expensive, depending on the rest of your pointcut.

Wes


DiFrango, Ron wrote:

> All,
>
> I could not find an answer to this in any of the old postings.  I have
> methods that take a common parameter.  The problem is that depending on the
> method call this parameter may be listed anywhere in the method signature.
> So for example:
>
> 	public class ParametersInMethodCalls
> 	{
> 		public void example1(ClassX x, double I, String s)
> 		{
> 		}
>
> 		public void example2(int I, ClassX x, double d)
> 		{
> 		}
>
> 		public void example2(float I, String s, ClassX x)
> 		{
> 		}
> 	}
>
> My question is can I define a pointcuts that picks out all the above
> combinations without having to "code if you will" the different permutations
> possible?  I have tried the following examples/permutations:
>
> 	pointcut examples(ClassX x) : 
> 		execution(public * ParametersInMethodCalls.*(..))
> 		&& args(.., x);
>
> 	==> Afected example2
>
> 	pointcut examples(ClassX x) : 
> 		execution(public * ParametersInMethodCalls.*(..))
> 		&& args(x, ..);
>
> 	==> Afected example1
>
> 	pointcut examples(ClassX x) : 
> 		execution(public * ParametersInMethodCalls.*(..))
> 		&& args(*, x);
>
> 	==> Affect nothing
>
> The important thing to note is that all the methods I want to pick out have
> the common input of ClassX, but there is an indeterminate number of other
> parameters to these methods.  Furthermore, I would prefer to avoid having to
> change the underlying code as it affects a large body of code.
>
> Thanks in advance,
>
> Ron DiFrango
>  
> **************************************************************************
> The information transmitted herewith is sensitive information intended only
> for use by the individual or entity to which it is addressed. If the reader
> of this message is not the intended recipient, you are hereby notified that
> any review, retransmission, dissemination, distribution, copying or other
> use of, or taking of any action in reliance upon this information is
> strictly prohibited. If you have received this communication in error,
> please contact the sender and delete the material from your computer.
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@xxxxxxxxxxx
> http://dev.eclipse.org/mailman/listinfo/aspectj-users