[jwt-dev] [architecture] Application mapping : services in JWT

[Marc Dutoo <marc.dutoo@xxxxxxxxxxx>]

Hi all

I've met yesterday with the other SCOrWare members. The aim of the 
SCOrWare public-funded project is to build a complete SOA / SCA 
platform, including runtime, tooling and demonstrators. Its process and 
workflow tooling is set to be implemented with and on top of JWT.

Obviously SCOrWare is very much service-oriented, as its two starting 
letters say it. The concept of service is also at the heart of the SOA 
vision and orchestration. Workflows are conceptually a notch above 
orchestration, but if we want it to be practical and easily allow SOA 
integration I really believe (please discuss) we should have an idea of 
what is a service in JWT.

So what is a service in JWT ?

Speaking in generic process concepts, it is a service call that happens 
inside an activity, mostly in an automatic (non manual) way. So it is 
nothing else than a specific kind of application, one that happens to be 
stateless etc. (making it all the way easier to call). In WfMC words, 
the connector used to map to this "service" application would be called 
a specific type of "ToolAgent", in Bonita of "Hooks", and in AgilPro of 
"Functions". Obviously in BPEL it is merely a web service invocation !

NB. I'm now replacing "services" with "web services" to make it more 
explicit. But other kind of services may also be considered (ex. JBI, 
REST etc.).

At the tooling level, it would be useful to
  * be able to configure in the JWT UI the application mapping allowing 
web service calls.
  * be able to configure this "web service" application mapping with 
the targeted service and its parameters.
  * This should enrich the metamodel with the right information, and 
typically our XPDL mapping should be able to process it for its plugged 
engine.
  * be able to choose the targeted web service using a service registry.
  * be able to validate the consistency of the targeted web services 
and its parameters.

For the last one we've already talked about validation frameworks like 
Recipe.

For the two last ones semantic technology like those provided by INT 
Evry and the University of Augsburg would be a powerful alternative. 
Think of choosing a service in the registry among only those allowed 
according to semantic annotations describing what its purpose is. Think 
of being able to match service call parameters and arguments, and plug 
adapters if need be (e.g. an adapter to reverse the parameter order).

Some questions about services in JWT :
  * should it be explicitly depicted in the metamodel ?
  * another registry is the process and package registry. Any synergy 
here ? Like using an ebXML registry for both as an implementation ?
  * Florian, input about your own semantic technology features and 
needs would be interesting !

Regards
Marc Dutoo
Open Wide