Re: message exchange patterns and # of parties

On Wed, 10 Sep 2003 22:55:36 +0600
Sanjiva Weerawarana <> wrote:
> I remember some discussion during the last F2F about the number
> of parties that may be involved with a single message exchange 
> pattern. I think I was arguing against having more than two
> parties as that's getting more into choreography space.

Err, umm.  No, in my opinion, any more than a description of more than
one party's participation is choreography.

> What did we decide? Are patterns allowed to have more than 2
> parties participating in a single pattern?

So far as I can recall, this was not one of the things ruled out.  Each
pattern description must now contain identifications of participating
nodes, but there is no ruling out of something such as the "third-party
request/response" (A -> Service -> C).

Multicast is apparently now to be handled by ignoring it, on the basis
that the fact of multicast is not important to *both* parties.  So an
output-only MEP may actually be delivered to multiple recipients; the
MEP is in this case construed to model the interaction between the
service and *each* receiving node (the service may send a single
message, and multiple recipients may receive it, but this information is
considered to be not visible in the description of the exchange

Amelia A. Lewis
Architect, TIBCO/Extensibility, Inc.

Received on Wednesday, 10 September 2003 13:08:33 UTC