[aspectj-users] cflow(within(C)) vs (within(C) || cflowbelow(within(C))

[Stephanie <stephaniechc-newsaj@xxxxxxxxx>]

I am new to AspectJ and is just trying to understand what each kind of
pointcut matches. So I wrote a simple class, SomeClass, and a simple
aspect, TraceClass, and was hoping that the aspect would print out all
the join points in SomeClass. To avoid infinite recursion, in
TraceClass I used "!cflow(within(Trace*))" as the pointcut. However, I
was not getting any output. Though "!(within(Trace*) ||
cflowbelow(within(Trace*)))" worked as I expected (printing something).
(From the post "cflow ( x()) && !cflowbelow( x()) " confusesme" I
gathered that cflow(x()) does not equal to (x() || cflowbelow(x())).
However, I still don't understand why my test doesn't work).

class SomeClass 
{
    static public void main (String [] args) {
    }
} // SomeClass

aspect TraceClass {

    // members
    static private int level = 0;

    static private void offset() {
        int i;
        for (i = 0; i < level; ++i) {
            System.out.print("  ");
        }
    } // offset

    pointcut pc() : 
        !cflow(within(Trace*))
//        !(within(Trace*) || cflowbelow(within(Trace*)))
        ;
    before () : pc() {
        offset();
        System.out.println("-> " + thisJoinPoint);
        ++level;
    }
    after  () : pc() {
        --level;
        offset();
        System.out.println("<- " + thisJoinPoint);
    }
} // TraceClass

In order to figure out what is happening with TraceClass, I added a
third class, TraceTrace, which prints everything happen
"within(TraceClass)". Again, when TraceClass used "!(within(Trace*) ||
cflowbelow(within(Trace*)))" it worked. However, when TraceClass used
"!cflow(within(Trace*))", the output was

=> staticinitialization(TraceClass.<clinit>)
  => set(int TraceClass.level)
  <= set(int TraceClass.level)
  => preinitialization(TraceClass())
    => initialization(TraceClass())
      => execution(TraceClass())
      <= execution(TraceClass())
    <= initialization(TraceClass())
  <= staticinitialization(TraceClass.<clinit>)

The after advice for preinitialization was never executed and no trace
for SomeClass was printed.

aspect TraceTrace {

    // members
    static private int level = 0;

    static private void offset() {
        int i;
        for (i = 0; i < level; ++i) {
            System.out.print("  ");
        }
    } // offset

    pointcut pc() : within(TraceClass);
    before () : pc() {
        offset();
        System.out.println("=> " + thisJoinPoint);
        ++level;
    }
    after  () : pc() {
        --level;
        offset();
        System.out.println("<= " + thisJoinPoint);
    }
} // TraceTrace

I use 

AspectJ Compiler 1.2 built on Friday May 21, 2004 at 15:06:22 GMT

and 

java version "1.4.2_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_01-b06)
Java HotSpot(TM) Client VM (build 1.4.2_01-b06, mixed mode)

Thanks,

Chi-Hua