Re: [aspectj-dev] -XlazyTjp and xlint-warning

[Matthew Webster <matthew_webster@xxxxxxxxxx>]

Oliver,

The answer is a quite subtle and there still might be a bug here. AspectJ
cannot use -XlazyTjp for around advice so you must attempt to use a pattern
for which it can be exploited then you will get the warning. Changing your
aspect:

public aspect TraceAspect {

    public static boolean enabled = true;

    pointcut toBeTraced() : execution(* *(..)) && !within(TraceAspect);

    before () : toBeTraced() && if(enabled) {
        Object[] args = thisJoinPoint.getArgs();
        System.out.println(thisJoinPoint + ", arg's: " + args.length);
    }

    Object around() : toBeTraced() && if(enabled) {
//        Object[] args = thisJoinPoint.getArgs();
//        System.out.println(thisJoinPoint + ", arg's: " + args.length);
        return proceed();
    }

}

will cause a warning. However if you restore the use of "thisJoinPoint" in
the around advice the warning will go away. I think _this_ is a bug because
if you code a pattern that can exploit -XlazyTjp and it cannot be used for
whatever reason you should be warned.

Matthew Webster
AOSD Project
Java Technology Centre, MP146
IBM Hursley Park, Winchester,  SO21 2JN, England
Telephone: +44 196 2816139 (external) 246139 (internal)
Email: Matthew Webster/UK/IBM @ IBMGB, matthew_webster@xxxxxxxxxx
http://w3.hursley.ibm.com/~websterm/

"Oli B." <boehm@xxxxxxxxxx>@eclipse.org on 24/03/2005 22:09:33

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cc:
Subject:    [aspectj-dev] -XlazyTjp and xlint-warning


Hello,

for the Option -XlazyTjp I used the Tracing example from the
README-12.html (a little bit modified):


public aspect TraceAspect {

     public static boolean enabled = false;

     pointcut toBeTraced() : execution(* *(..)) && !within(TraceAspect);

     Object around() : toBeTraced() && if(enabled) {
         Object[] args = thisJoinPoint.getArgs();
         System.out.println(thisJoinPoint + ", arg's: " + args.length);
         return proceed();
     }

}


from the README: "The optimization is disabled at join points advised by
around advice, and an Xlint warning will be displayed in these cases."
But when I compile it (ajc -XlazyTjp -Xlint:warning -inpath src -d
classes src/lazy/tjp/*) I expect to get a warning -- but no warning
appears (AspectJ 1.5.0 M1).

regards
Oliver
--
Oliver Böhm
http://www.javatux.de

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