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From "Assaf Arkin" <ar...@intalio.com>
Subject Re: PXE implementation basis
Date Fri, 07 Apr 2006 06:21:05 GMT
Names (or channels) would be the equivalent of EPRs + correlation sets. You
can create new ones in the process, for EPRs those were typically be fixed,
but with correlation sets that gives you distinct names for each process
instance. The ones you create, you can only listen on (myRole). You can also
send them to other processes (put them in a message), receive them from
other processes, and use the ones you received to communicate with those
other processes (partnerRole).

Having a process definition and executing one activity after another (e.g. a
sequence) is the equivalent of reducing it until there's nothing left to
execute. So a process definition of the form P = a.b.c is simply a sequence
of three activities.

There's one thing that takes a while to get used to. A pi-calculus process
may reduce to nothing, but a BPEL process never reduces. That's because a
pi-calculus process P = Q | R has two processes (Q and R) which exchange
messages with each other and can eventually complete. In BPEL you would use
the process construct to define Q, or two define, it will take both of these
to come up with a process that reduces.

BPEL doesn't have a construct for wrapping Q and R into an actual entity,
but given the partnerLinkTypes that express the channels between Q | R, the
overall reduceable process P can be deducted.

Assaf

On 4/6/06, Matthew Stevens <Matthew.Stevens@sun.com> wrote:
>
> FWIW - if you stumble on Agha or are totally lost (like me) I frankly
> found these and other Wikipedia topics quite clear (certainly a lot
> easier than reading the academic papers).
>
> http://en.wikipedia.org/wiki/Process_calculi
>
> http://en.wikipedia.org/wiki/Actor_model_and_process_calculi
>
> http://en.wikipedia.org/wiki/Actor_model
>
> still lost,
> matt
>
>
> Alex Boisvert wrote:
> > You can refer to the biography section of the PXE website:
> >
> > http://pxe.intalio.org/confluence/display/PXE/Agha86
> >
> > alex
> >
> > Bill Flood wrote:
> >
> >
> >> We are trying to understand the PXE contribution.  Is this the
> >> implementation basis for PXE?
> >>
> >> http://www.labri.fr/perso/grange/documents/fmppta.pdf
> >>
> >>
> >>
> >
> >
>
>


--
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