I don’t normally have much to say on BPEL (as a language for orchestrated processes). A BPEL engine can be used to execute business processes and actions post-”complex event detection”, but at the end of the day its just a particular - albeit common and standards-based - technology for executing process orchestrations [*1].

On the other hand, state management of entities is particularly interesting for Complex Event Processing. In a nutshell, the state of some entity will often determine some event pattern detection, as well as the relevance of certain business decisions, operations / processes, and actions. CEP tools handle state, and some (like TIBCO BusinessEvents) actually allow developers to model state explicitly - usually for entity lifecycle management, including complex event pattern lifecycles…

It was therefore somewhat fascinating to find a new IBM initiative called BPEL4Data and an associated Business Entity Definition Language (BEDL) comprising of entities and state models (and indeed, almost MDM-like data management operations) [*2].

One trick I think the IBM team have missed is in tying themselves to (another reinvention of) BPEL. State models involve states and event-driven state transitions: to me this means that states are part of the behavior of entities, an active not a passive attribute. And conditional state transitions mean rules rather than processes. Ergo its no accident that TIBCO BusinessEvents state models are defined in an environment that combines them with events and declarative rules.

Of course BPEL - and orchestrated BPM - have their place and use cases - indeed TIBCO has many successful BPM customers, some of whom are combining entity models and states (in TIBCO BusinessEvents) to control workflow processes (in TIBCO BPM). There are indeed many patterns to combining event-based state changes with process orchestrations, and IBM’s focus on just one will be interesting to watch.

Notes:

[1] TIBCO’s BPM group of course has much more to say on BPM and BPEL …

[2] TIBCO followers will be bemused by the acronym overloading here:
- IBM BEs (Business Entities) are directly equivalent to TIBCO BE (BusinessEvents) concepts, with UML-based state models applicable to both.
- IBM BEs map via IBM BPEL4Data to BPEL business processes, whereas TIBCO BE concepts and states are directly executed in the TIBCO BE rule engine (with no BPEL intermediate step, if you like), with BPM processes as optional (downstream) activities.

Nice to see a paper on IBM Developworks on some of the theory of “event processing”, authored (amongst others) by the Chair of the Event Processing Technical Society, IBM Labs’ Opher Etzion, and fellow EPTS Reference Architecture team member Catherine Moxey. The paper is of course somewhat of a “broad brush” view of event processing, as indeed you might expect from a team representing such a diverse range of event-handling software as Tivoli, CICS, MQ and so forth from the broad (and, from a TIBCO perspective at least, heavyweight ) IBM software stack.

Some thoughts:

1. The paper implies a need to model, in any significantly large event processing system, the types and roles of the event processing agents and how they interact. Some such agents will be tightly coupled (such as co-operative rulesets in a TIBCO BusinessEvents inference agent), whereas others will have more identifiable interfaces and roles (such as separate inference and query agents in a distributed TIBCO BusinessEvents application). Tables 6 and 7 for example are almost metamodel definitions for an event processing agent.
2. Possibly a better name for the paper would be “A Conceptual Model for Event Processing Networks“, given the emphasis on event pathways through processing agents.
3. IBM Developerworks (like this blog) has an unattributable “scoring mechanism”, and shows today that one reader was unimpressed enough to profer a low score - but why? I also can’t explain why this is described as aimed at an “intermediate” audience, as the principles seem basic and well explained…

… with the announcements and discussions of Microsoft’s SQLServer-or-.NET-library-no-one -seems-quite-sure-yet stream processing tooling, and then IBM’s you-can’t-have-too-many-CEP-tools System S announcement. Looks like IBM has donated this software to some good causes as part of its beta program - good on IBM - although presumably future users will be expected to pay for the technology.

These arrivals mean that, finally, all the Big 3 (Oracle, IBM, Microsoft) have now declared some interest in query-based stream processing. Possibly this will increase interest (from a somewhat low base) for standardising SQL extensions (syntax and semantics) for continuous queries (as also provided for in TIBCO BusinessEvents 3.0 and later). We’ll see…