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Re: control construct

From: David Martin <martin@AI.SRI.COM>
Date: Mon, 20 May 2002 16:25:10 -0700
Message-ID: <3CE985D6.4E583812@ai.sri.com>
To: Dan Wu <dandan@cs.umd.edu>
CC: www-ws@w3.org
Dan Wu wrote:

> hi, I am very confused about the Split, Split + Join and Choice
> construct in DAML-S.  Anybody has examples showing what these
> constructs means and how to use them?

Dan -

There are are no examples available currently that use Split or Split
+ Join.  But the Congo Process Model, available here:


does illustrate the use of Choice.  None of these constructs is new;
that is, they have been used before in various process modeling
languages.  You may find some relevant info (or at least some relevant
citations) here:


under "Background Material on the Process Model" (but I'm not
personally familiar with that material, so I'm not sure what you'll

Finally, here's a brief explanation volunteered by another of the
DAML-S contributors:

"Split is like spawning or forking off processes. Split+join means
forking and synchronizing (like waiting for the spawned processes to
complete). A service provider may chose to model a split process to
take care of a shipping request and not wait for it's completion
before making/allowing other transactions. A credit card verification
process may involve spawing off a authentication and/or validation
requests (same or different processes) and waiting for it's (their)
return before proceding further. This is an example of split+join. "

I hope this helps some.

David Martin
Received on Monday, 20 May 2002 19:20:12 UTC

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