[aspectj-users] Changes in introduction for aspectj compiler 1.1

["William DeMoss II" <wdemoss@xxxxxxxxxxxx>]

I was playing around with porting over our current project witch uses
1.0.6 to the new compiler and looking into the little differences that
would need to be addressed. I came across a obscure difference between
the two concerning introduction. I thought it would be of help to pass
it along. Here is the example.

    interface Identifiable {
        void setId(Id id);
        Id getId();
    }

    aspect IdentifiableAspect {
        private Id Identifiable.id = null;
        public Id Identifiable.getId() {
		return this.id;
	  }
        public void Identifiable.setId(Id id) {
            this.id = id;
        }

        public int Identifiable.hashCode() {
            return (this.getId() == null)
                ? super.hashCode()
                : this.getId().hashCode();
        }
    }

The method of interest is the introduction of hashCode. Proir to the new
compiler this worked fine. Now it throws a NullPointer exception in the
compiler w/o a good error message. However, if you change the
functionallity to the following:

    int around(Identifiable i): target(i) 
        && call(public int hashCode()) 
    {
        return (i.getId() == null)
            ? proceed(i)
            : i.getId().hashCode();
    }

It accomplishes the same goal. I believe this has to do with the new
compiler  bytecode weaving as opposed to the source code weaving done
with the prior version. Hope that can save someone some trouble.

- wd