Hi Everybody,
I have implemented all WS Coordination, AT and BA Specifications on .Net
platform. However, my design is technology independent and it can be easily
implemented on any platform. If anyone is interested i can send the source
code.
CC Bimalee: feel free to contact me for any assistance.
CC Hannes: I doubt the appropriateness of WS-Business Activity Initiator
protocol. In BA scenario, the initiator itself becomes the coordinator. In
contrast to AT Specification, the abstract nature of the BA Specification
allows the Initiator to decide the coordination logic. In such situations where
the coordination logic resides within the Initiator application (eg: workflow
engines), it is highly unlikely to use an external coordinator.
However, I agree the fact that the introduction of a WS-Business Activity
Initiator protocol is possible and it is in accordance with the BA
Specification.
When the Initiator ad Coordinator becomes two different entities, the
Initiator requires to know the status information of all the participants
(which coordinator possesses) and the coordinator need to know the coordination
logic (which Initiator possesses). Therefore, such a new protocol should be
capable of exchanging all the information (these information could be
application specific as well) between the Coordinator and the Initiator.
Considering the amount of information exchange, it is very important to
reduce the transportation overheads/ delays. Usage of a new WS-Business
Activity Initiator protocol will require this communication to happen by means
of Web service requests/ responses which is costly.
The question arises is that considering the usage scenarios of BA such as
workflow engines, whether is it necessary to separate the Coordinator from
Initiator bearing the aforementioned overheads and difficulties.
In my implementation I have made the Coordinator and Initiator to be a single
entity and the coordination logic to be part of the application code. The
coordination rules for each Coordination Type (Mixed outcome and Atomic
outcome) is managed outside the application code and hence, the application is
free from unnecessary burdens.
However, there can be scenarios where the existence of an independent trusted
Coordinator is essentials. My implementation supports such scenarios by
encapsulating the coordination logic within the Coordinator and allowing it to
run independently. In such scenarios, participants can join the business
activity using participant protocols defined in BA Specification.
Regards
Sanjaya
Hi Bimalee,
> In the mailing list we have seen that there are some people who have
> already implemented this specification. It would be a great if they can
> share their experiences with us.
Georg and I have more or less completed the WS-BA implementation for
Kandula 1. We are currently working on a "real world" demonstration
application to include with the source code and hope that this will help
mature our code to have it released to the public.
As the WS-BA specification does not include the initiator<-->coordinator
interface we defined a new "WS-Business Activity Initiator" protocol to
fill this gap. Unfortunately we are still waiting for our univiersity's
approval to publish it, but are looking forward to get it in the next week.
As to Kandula 2: if you don't want to do a complete rewrite of
everything, all you need to do was to insert the WS-BA hooks to the
existing WS-BA implementation into the kandula 2 core.
The WS-BA implementation Georg and I did does not require a specific
axis implementation, I guess with some minor tweaks it should also run
on Axis 2.
Best regards and season's greetings,
-hannes
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