[aspectwerkz-user] Re-visitng AspectWerkz

Hello All

 

I'm re-visiting AW after quite sometime, the last release I used was AW 0.9
but after that the aspect/interceptor strategy changed a little bit and was
not accommodating to my requirements. I would like to state my scenario and
would be greatly helpful if someone could tell me if it is possible or not
and point me in the right direction.

 

I use the term "interceptor" instead of "aspect" (that are self-contained in
AW) because in my case the "binding" of an advice to one or more pointcuts
should be external or at least easy to accomplish without having to
re-deploy the aspect.

 

We are using AOP as a "tool" and not as "coding style" for the purposes of
policy enforcement on our EJBs. Our policy enforcement mechanism is expected
to allow binding at run-time any number of "interceptors" to one or more
"pointcuts" where these pointcuts would basically reflect individual
operations on the EJB. Similarly there should be capability to detach these
interceptor bindings and swap them for something else. It would be a bonus
if there was a capability to compose one or more commonly used interceptors
inside a stack and attaching this stack to a pointcut. 

 

a)       At deployment time of the EJB I would like to pre-compile the
classes based on the pointcuts which are one for each of the operations.
There may be some or no interceptor binding definitions at this point but in
essence "preparing" the target to accommodate interceptors for the future.

b)       To be able to deploy a new "interceptor" at run-time which means
class-loading the code, etc and make it available for attaching and
detaching them to already "deployed" pointcuts.

c)       To be able to swap one or more interceptors at run-time from
pointcut binding. This is basically the capability to attach and detach
interceptors to and from pointcuts that are essentially EJB operations. And
at the time of the service invocation, the effect of interception is
realized instantly.

d)       To be able to define one or more attributes/parameters on an
Interceptor that is nothing but ad-hoc name-value pairs and should be
visible inside the interceptor code.

e)       To be able to define one or more attributes/parameters as
"meta-data" at the class and method level and there should be a capability
to read this meta-data from within the interceptor code assuming it is bound
to the right pointcut.

f)         To be able to "name" interceptors borne out of the same class so
that I could create an "Interceptor1(class=com.xyz.Interceptor) and
Interceptor2(class=com.xyz.Interceptor) and have different attribute values
for each of them to be used for different purposes.

 

I was able to do a good deal of this in AW 0.9 but the strategy considerably
changed after that and I switched to JBoss-AOP which allowed me to do all of
this. But for various reasons I'm also interested in AW considering there is
a lot of interest around it and with AspectJ integration. 

 

It wasn't obvious to me as to what I can or cannot do with 2.0. Your
analysis and inputs are greatly appreciated.

 

Thanks

Rajiv Kadayam