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Sending a one-way message to WSA "none".

From: David Hull <dmh@tibco.com>
Date: Wed, 29 Nov 2006 12:30:45 -0500
To: "xml-dist-app@w3.org" <xml-dist-app@w3.org>
Message-id: <456DC3C5.8090909@tibco.com>

WSA defines a "none" address (http://www.w3.org/2005/08/addressing/none)
and says that sending to it means making an HTTP connection to
www.w3.org and ... oh wait a minute, I made that last part up.  Sending
to "none" means not to send at all.

This is probably sufficient for WSA's purposes, but it's interesting
that it can also be described concisely in terms of the three duties I
put forth [1]:

   1. What is the set of receivers? The empty set.
   2. For each receiver, what is the message path? Since there are no
      receivers, the "for each" is vacuous.
   3. For each receiver, ensure the message received is the same as the
      message sent.  Again the "for each" is vacuous.

What's more interesting (to me, at least) is that this three-part
formulation also covers anonymous and the typical HTTP "async" case
using r-o-r, making good on the WSA notion that "The basic interaction
pattern from which all others are composed is 'one way'. In this pattern
a source sends a message to a destination without any further definition
of the interaction."

To put the third part in the form of a question for binding writers to
answer, and because a MEP description is supposed to address fault
disposition, I'd re-phrase it as

   3. For each receiver, when will the received message be the same as
      the message sent, and when and how will a fault be signaled?

(note that there may be cases when we don't know that either of these
things will happen).

Answer those three questions and you've got yourself a binding.

[1] http://lists.w3.org/Archives/Public/xml-dist-app/2006Nov/0001.html
Received on Wednesday, 29 November 2006 17:31:04 UTC

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