You're confusing the concept with a means of implementing the concept.
Also, I don't mean to imply that Service ECA Rules are the only way of
implementing the concept, but they are one way. That is why I
recommended that you look at how SECA rules are used in OFBiz (like
triggering order item completion with a shipment is packed, order
completion on order item completion, and by the same means invoicing
and many other business processes).
It is not an enterprise-wide form of EDA, just like the service engine
is not an enterprise-wide form of SOA. If enterprise-wide SOA and EDA
tools are used OFBiz can integrate easily with these since internally
it is architected using the same principles (ie can consume and
produce services, and can generate and listen to events.
-David
On Jan 17, 2009, at 10:17 PM, Raj Saini wrote:
I see the events in a event-driven system are emitted by some
sources (or agents) and consumed by consumers ( sinks). Sinks have
the responsibility of applying a reaction as soon as an event is
presented. Generally, event are transmitted among loosely coupled
software components. One important think to note here is that source
and sinks may not be aware of each other in the event processing and
hence this results in the highly modular and loosely coupled
applications.
I apologizes if I am wrong but I see ECAs as interceptors similar to
the aspect oriented stuff and they are triggered as part of the call
to service.
Thanks,
Raj
David E Jones wrote:
It would not be correct to say that EDA (Event Driven Architecture)
and ECA (Event-Condition-Action rules) are the same thing. It would
be correct to say that ECA Rules are one way of implementing an
event-driven architecture (EDA).
If you look at how ECA rules are used in OFBiz you'll see it is
very consistent with the general EDA concepts. With all logic
flowing through the Service Engine in OFBiz it becomes a natural
hub for business events, and ECA rules allow us to do things based
on those business events.
If you disagree, please do share. How is your vision of an EDA
different from how we use ECA rules in OFBiz?
-David
On Jan 17, 2009, at 9:07 PM, Raj Saini wrote:
Is ECA same as EDA? I feel ECAs in OFBiz are more like
interceptors/triggers where are EDA is all together a different
architecture pattern. This is a good document explain EDA:
http://www.eaipatterns.com/docs/EDA.pdf
Thanks,
Raj
Jacques Le Roux wrote:
I think, as a marketing effort, we should put 2-3 sentences about
SOA (Service Oriented Architecture) and EDA (Event Driven
Architecture) OFBiz's features on main site, in "Introduction:
What is Apache OFBiz?" section for instance.
Buzz words (acronyms nowadays) can't hurt if we want more
recognition. And it's easier to be understood by using SOA
acronym than Service Engine and especially EDA instead of ECA. Of
course a sentence explaining quickly both concepts is needed.
Any takers ? (several would be better...)
Jacques
