[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: RE: [ogsi-wg] RE: [ws-caf] WS-Resource Framework
Hey all, Since Mark asked for my comment... [...] > I'm still waiting to see what the real differentiator is in the useage > pattern, the interaction pattern, or whatever that means that this > couldn't > have been achieved with WS-RF. If you look at the paper that Savas et al. > produced many months ago, doesn't that map to precisely the same goals, > but > using WS-Context at the core? Hopefully Savas can comment on this too. > [...] (lots of [...]) Mark, I agree with your arguments (I know... that doesn't happen very often :-) In our paper all those months ago we wanted to present a way to do stateful interactions in a service-oriented fashion. WS-Context provided us with the means to do just that. We wanted to model stateful _interactions_ through message correlation. There are many ways for doing this: - BPEL uses properties from application messages to model stateful interactions. - One could use information in the messages to explicitly correlate messages (e.g., order numbers explicitly sent as "arguments" to operations) (similar to the above really). - One could overload the semantics of a service and introduce "service instances" (the OGSI approach and we know how that ended). - Or, contextualisation could be used. WS-Context was the only specification at the time explicitly talking about contextualisation (and still the only one as far as I know). Your choice of any of the above methods is application-specific. If you want to model stateful interactions with a particular resource, you could do it with any of the above ways. The WS-RF authors decided to use WS-Addressing, which is fine. It means that parts of a WS-Address structure will have to travel as headers in a message. It's a form of contextualisation. However, it's not different from WS-Context which scales better to multiple participant interactions. I can't see how this could be done with WS-Resources. Could WS-RF have used WS-Context? Sure! No doubt about that. I would welcome an effort by the two communities to bridge their differences. Until then... let's build some applications to test the ideas: http://www.neresc.ac.uk/ws-gaf/AboutWSGAFApplication.html. Best regards, .savas.