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RE: Terminology Question

From: Assaf Arkin <arkin@intalio.com>
Date: Sun, 23 Feb 2003 16:13:59 -0800
To: "Burdett, David" <david.burdett@commerceone.com>, <jim@ironringsoftware.com>, <www-ws-arch@w3.org>
RE: Terminology QuestionDavid,

I was about to raise an issue regarding the use of MEP in the WSA document.

A message exchange pattern can be as simple as a WSDL operation, but in fact
can also be as complex as a long-lasting multi-party choreography. Unless we
restrict the definition of MEP, I would say that Wsb services choreography
also addresses MEPs and MEP is just another way to define a conversation.
And in fact several people have proposed extending MEPs to the point where
they tread into the space of choreography.

I suggest that we formally define WSDL as capturing a specific type of MEP
which, as Amy said before, attempts to capture the basic communication
idioms (synch, asynch, unicast and multicast) with the restriction that each
WSDL MEP contains the minimal number of messages required for such an idiom.
A choreography language would then provide more complex MEPs using these
communication idioms.

  -----Original Message-----
  From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
Behalf Of Burdett, David
  Sent: Sunday, February 23, 2003 3:56 PM
  To: jim@ironringsoftware.com; www-ws-arch@w3.org
  Subject: RE: Terminology Question

  For what it's worth here's are my ideas based on what other groups such as
ebXML and WS Choreography tend to use (I am off-line and so can't quote)
Really there are two levels:

  1. Message Exchange Patterns are a short exchange of messages such as
one-way or request-response, together with associated
acknowledgement/receipt messages.

  2. A Conversation consists of a combination of Message Exchange Patterns
where all the messages are related in some way.

  The word "Conversation" is used because the exchange of information can
consist of an indeterminate number of exchanges of information as in a real
conversation between people. A classic example of a conversation is the
sequence of messages exchanged to place and/or change an order:

  BUYER                     SELLER
         Order -------->
               <-------- Order Response
  Change Order -------->
               <-------- Change Order Response
  ... repeat change order as required ...
  Cancel Order --------> (only if required)
               <-------- Cancel Order Response



  -----Original Message-----
  From: jim.murphy@pobox.com [mailto:jim.murphy@pobox.com]
  Sent: Friday, February 21, 2003 1:59 PM
  To: www-ws-arch@w3.org
  Subject: RE: Terminology Question

  So the collection of messages that manifest the exchange would be

  Jim Murphy
  Mindreef, Inc.

  > -----Original Message-----
  > From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]
  > Behalf Of Francis McCabe
  > Sent: Friday, February 21, 2003 4:34 PM
  > To: jim@ironringsoftware.com
  > Cc: www-ws-arch@w3.org
  > Subject: Re: Terminology Question
  > This is a message exchange pattern
  > On Friday, February 21, 2003, at 01:30  PM, <jim.murphy@pobox.com>
  > wrote:
  > >
  > > Speaking of definitions, what term are folks using to describe the
  > > collection of messages that occur when an operation is invoked.  For
  > > the
  > > typical input/output operations you would have 2, a request and a
  > > response. In a one-way you would have 1, in a solicit response you
  > > would
  > > have n etc.
  > >
  > > What moniker would y'all recommend for this collection:
  > >
  > > 1.  Exchange
  > > 2.  Conversation
  > > 3. ???
  > >
  > > Something that indicates the fact that these messages are part of
  > > same operation is the critical part for me.
  > >
  > > Thanks.
  > >
  > > Jim Murphy
  > > Mindreef, Inc.
  > > http://www.mindreef.com
  > >
  > >
Received on Sunday, 23 February 2003 19:15:36 UTC

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