vincent
08-19-2008 03:24 PM
Apart from classic Complex Event Processing (event abstraction across time, source, type and attribute) applications for situation-awareness type problems,
TIBCO BusinessEvents is also finding uses in sophisticated / dynamic event-driven processes that cannot be fitted easily / entirely within representations such as
BPMN,
BPEL, etc. Of course, there are many other ways of deploying complex processes across services: consider the
wsper project, for example, that aims to exploit and combine
WSDL,
SCA and BPEL [*1]. Their provided
example, interestingly, also maps very nicely onto an
EDA using a combination of state model + rules, which have the added advantage of declarative rules that can handle any out-of-process (i.e. complex exception) event [*2] - something BPEL can’t handle [*3].
Notes:
[1] I don’t agree with the wsper metamodel (documented
here), which defines an “event” as a subclass of operation, and “state” as an attribute only of event. This seems far too restrictive, although it might fit wsper’s SOA perspective.
[2] Consider the (unfortunate) case whereby, in the supplied HR
example, your job candidate “expires” (RIP) in the middle of this process.* You would not want your business process to attempt communication with
the dead - you need some flexible, declarative, cross-process exception mechanism. This is typically handled by a “rule”…
[3] On the topic of BPEL we also note
one effort looking at retrofitting “event processing” constructs into BPEL. Why not
event-driven COBOL, too, one wonders? A more interesting project would surely be standardize the event modeling level (e.g. extend
BPMN for CEP, or map
CEP to BPDM), rather than trying to force event processing into BPEL (insert here visions of pigs in party frocks). No doubt this topic will come up for some (lively) discussion at the
EPTS meeting on CEP standards next month…
Source...
08-20-2008
