Nice overview article of Complex Event Processing (CEP) and SOA by David Cameron on TMC. Just one snag - he thinks that Business Rules are "... best suited to problems where the process steps are linear and predictable and don’t require contextual information about timing and sequence of event patterns". Now I agree with him that event processing does require some additional specialized technology but at the end of the day you have to make a business decision what to do. The justification for using business rules to manage this decision and automate it is the same as taking control of decisions in repeatable processes - business owners can control the response, the response can be changed more quickly and consistency of response across situations can be better enforced (precision, consistency, agility). I am looking forward to the next article but meanwhile check out the section on Event Processing on my other blog.
UPDATED: It was pointed out to me that David wrote an article on ebizQ as well "Using CEP to Address the Five Challenges of SOA". In thishe says
"Ultimately services make decisions by applying the logic programmed into them to the data they are given. But what if that logic changes frequently so that it becomes difficult to maintain inside the service? "
Indeed, what if? Well then you should be using business rules to develop these services so that the logic in them can be changed by business users in a controlled manageable way. Check out this post or this one for more on rules and how they can deliver agility.
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I appreciate James' comments and we are on the same page. The article actually states that business rules ENGINES (i.e. the technology tool, along with BPM and BAM) are "best suited to problems where the process steps are linear and predictable and don’t require contextual information about timing and sequence of event patterns."
The reason for this is that most rules engines today require all of the data used in the rules, including the contextual data involving timing and sequence arrays, to be built in advance and stored in a database - creating very complex, ultimately unmanageable data structures for the types of applications in my article. CEP maintains this latter contextual information natively with the event messages, dramatically simplifying the building and maintenance of rules so they can be changed often by non-techncial users.
CEP does, in fact, use business rules (i.e. the generic definition) and, when done properly, these rules can be built by a business user. That said, it is rare for an IT department to willingly relinquish control over the business logic to the line of business folks (though one could argue they should, for a variety of business and selfish reasons).