A truism about SOA is that its all about automating the interaction of
processes that are already automated. In other words, an SAP or Oracle supply
chain application might invoke a weather forecasting service from an external
program and automatically adjust promised delivery dates without the need to
get a human involved in a process.
But of course, if business only relied on automated processes, then the world
would look like something out of a Jetsons cartoon. In actuality, sometimes
you cant fully automate processes such as that delivery date commitment
decision. Suppose you needed to make a delivery commitment to the Gulf Coast
just before Katrina was to strike? Short of possessing true AI and a crystal
clear crystal ball, youre going to have to call a person into the process
where the scenario is so exceptional that it requires human intuition.
This week, IBM,
joined by SAP, Oracle, BEA, Adobe, and Active Endpoints formally proposed a
pair of specs for submission to Oasis, the web standards body, which would
make human workflow a first class citizen in an SOA environment (for now, well
call this group the WS-folks). There was little surprise to the announcement,
except for the fact that Oracle dropped its former opposition to the scheme.
The new proposal boils down to two specs: an extension of BPEL that adds human
workflow as one of its orchestration steps, and a new proposed spec, WS-Human
Task, where the actual workflow would be described. Backers claim that, by separating
out human tasks, that they can stand alone and be invoked without having to
go through a BPEL orchestration. That would enable you to decouple the task
from the actual application or user interface, making it that much more reusable.
This all sounds fine and dandy except for one thing - the classic BPM
folks are still not among the signatories. Both sides have been warring back
and forth, with many of the established BPM players claiming that BPEL is simply
a rudimentary execution language that does not reflect the subtleties of a process
workflow. For instance, it doesnt represent core concepts like swim
lanes that are used for describing parallel activities. They claim that
BPEL in fact complements a couple other standards, including BPMN, a graphical
notation for process models, and XPDL, an older specification first developed
by the document management and workflow communities.