[Mockobjects-java-dev] AOP : Aspect Oriented Programming

[Vincent M. <vm...@oc...>]

I have discovered AOP this week end (AspectJ) and found it very very
interesting, especially for unit testing purposes. I highly suggest that you
take 30 minutes to an hour to read the "getting started" paper
(http://aspectj.org/doc/gettingStarted/index.html).

I find the idea great. In a few words, the idea is that there exist some
crosscutting aspects (hence the name: AspectJ) that encompasses several
methods. For example, let's say you want to log the entry and exits of
methods. This is a general pattern. In java, it would be very difficult to
materialize this aspect. You would have to add log statements at the
beginning and end of each method, but still you would not have captured the
pattern. Also, if you add a new method, you have to remember to add log
statements.

AspectJ let you describe aspects in its own semantic (near java). Then, you
apply the aspect compiler which will transform the code in java and invoke
the javac compiler to compile it.

It is very very powerful. You can say things like verify that such method is
only called by such other method when it is in such context. There are
better examples (with code) given in the paper highlighted above.

Just wanted to let you know
-Vincent