[aspectj-users] Re: [NEWSDELIVER] Multiple instances of the same class w

[Matthew Webster <matthew_webster@xxxxxxxxxx>]

Didier,

There are 3 possible approaches:
1. Read Adrian's blog: http://www.aspectprogrammer.org/blogs/adrian/2005/03/perinstance_asp.html.
Your class will be woven with all the aspects but you can choose which
ones are active for a given instance.
2. Some AOP frameworks use proxies to
allow advice to be added removed. However this is not yet supported by
AspectJ 
3. Create 2 different subclasses of
C and weave those with the desired aspects.

Cheers

Matthew Webster
AOSD Project
Java Technology Centre, MP146
IBM Hursley Park, Winchester,  SO21 2JN, England
Telephone: +44 196 2816139 (external) 246139 (internal) 
Email: Matthew Webster/UK/IBM @ IBMGB, matthew_webster@xxxxxxxxxx
http://w3.hursley.ibm.com/~websterm/

To:        Matthew Webster/UK/IBM@IBMGB
cc:        
Subject:        Re: [NEWSDELIVER] Multiple instances of the same class woven against different aspects in an Eclipse plugin [Cross-post]


Hi Mattew!

Thanks for your quick answer.

Let me give you an example of what i try to achieve:

I've got a class C, and two aspect A1 and A2 and i need to instanciate
some instance of C with application of A1 and some instance of C with
application of A2.

As a real-world example, i could say:

I've got base implementation C of a graph of processing node.

A1 is the composition of three aspects: event management (aka observer),
assertions checkings and change collection/application/propagation on
the network

A2 is the composition of two aspects: change
collection/application/propagation on the network and mapping to an
external processor.

Thus in the same VM i may use two versions of C.

Am I more clear ?

Thanks for your help!
Didier.

Matthew Webster wrote:

>
> Didier,
>
> >I try to write an RCP app in which i need multiple instances of the same
> >classes woven against different aspects.
> I'm not quite sure I understand what you are trying to do. The JVM
> will only allow one version of a class in the system at once unless
> they are defined in different, unrelated bundles. Can you explain what
> you are trying to achieve.
>
> The simplest way to try LTW is to use the Java 5 agent
> (http://www.eclipse.org/aspectj/doc/next/adk15notebook/ltw-agents.html).
> We have also just launched an Equinox incubator project to better
> support aspects in OSGi
> (http://www.eclipse.org/equinox/incubator/aspects/index.php). Over the
> next few weeks we will be filling out the Web site and populating the
> repository.