CEP as sauce for the alphabet soup (Part 6): SOA
Posted by Paul Vincent
I saw an interesting article on CEP and SOA which means it must be time for another dose of alphabet soup: how does CEP relate to Service Oriented Architecture?
SOA is all about distributing your applications as components, implemented as separate services (for example, but certainly not exclusively, as web services) so that applications can share said components/services. Naturally, there is also a strong correlation with BPM [*1] (also commented on in an earlier soup ingredient) - automated business processes can be mapped to independent services for both process and service re-use. CEP fits into SOA as well as it fits into BPM - for ancillary (and ideally rule-driven) services such as SLAs, policy management and so forth. For more detail on CEP in SOA check out this more detailed article by TIBCO’s Alan Lundberg.
So:
* Service invocations can be considered events, and tracking those can be useful for the event-driven enterprise.
* Real-time services require an Event Driven Architecture which in reality can be considered as a large overlap with an SOA. Run-time event processing services may be complex, and can therefore be handled by CEP systems.
In the aforementioned article it is mentioned that CEP can also benefit from SOA - “most CEP engines possess fragmented techniques — read vendor lock-in — for executing real time event processing all of which could greatly benefit from already exposed SOA designs”. However, it is not clear what the author means here:
* vendor lock-in is much less of a problem if you deal with organizations (like TIBCO) commited to standards
* SOA “designs” are not primarily “event driven” or “event focused” so don’t contribute much to the concept of CEP - unless one means established (and pre-SOA) concepts like rule-driven event correlation, combining event processing and business rules, etc
For the final say on SOA, we can only defer to Greg The Architect and his dealings with some of the other “venduhs” out there… 
Notes:
[*1] Naturally, there is a strong correlation too with software stacks that provide integrated BPM and SOA solutions, which are even better when combined with CEP…
BPM, Complex Event Processing (CEP), SOA | 05 July 2007 |
