- From: bhaugen <linkage@interaccess.com>
- Date: Wed, 26 Feb 2003 07:21:04 -0600
- To: public-ws-chor@w3.org
Assaf Arkin wrote: > BPEL4WS, BPML, WSCI, etc are based on processes defined for each > communicating agent, dating back to the model proposed in CSP and later > refined in pi-calculus and other works in that space. BPSS and EBPML prefer > to express processes as a centralized sequence of exchanges and then each > agent has to derive its process by extracting all activities related to some > role. > I think there's conversion from one to the other, but I don't have evidence > that you can move from the CSP model to the centralized one and back without > losing some information. I don't think it is accurate to describe BPSS as "centralized". It was derived from the UNCEFACT Business Collaboration Protocol metamodel, which is a state-alignment protocol. That is, the protocol is intended to align the states of "common knowledge" or mutually-agreed-upon state machines, which may be implemented using the Half-Object-Plus-Protocol pattern. (Nothing centralized.) The protocol does make a distinction between external collaborations (whose states must be aligned) and internal activities (whose states are none of anybody else's business). So if you took a model which included both external and internal activities (in this sense), and moved to BPSS, the BPSS representation would only include the external activities. That does not mean the internal activies would be lost. It's just a separation of concerns. -Bob Haugen
Received on Wednesday, 26 February 2003 08:22:03 UTC