I did not thought on having a feature like that. Can be great if you
can provide some case study for it.
IMHO doing something similar to gin, should not be that difficult. At
least when it comes to provide a "factory" for the intercepted
classes.
What it struggles me a bit more, is how the methods interception are
defined. Since you don't want to modify the classes, I guess you less
want to annotated their methods. Maybe a good approach is using
Matchers as GIN does.
I believe this feature is more in the scope of GIN. In fact they have
plans to introduce AOP some day.
http://code.google.com/p/google-gin/issues/detail?id=38
I'm developing this 'framework' together with a real application. So,
the features are a bit driven for the needs of my application. But an
integration with GIN is a must someday I will need to face.