RE: Comment on Fragment Identifiers

Sorry, not the first time I've messed up the capitalization - the
{direction} token is an enumeration of "in" and "out" (note lack of
capitalization!), and I really need to double-check which property values
are capitalized and which aren't before putting fingers to keyboard...

<input> maps to {direction} = "in".  <output> maps to {direction} = "out".
But as Amy says, when you can have multiple messages in a single direction
within a MEP, {direction} is insufficient to identify them.  {message label}
provides a unique token for messages within a MEP with which to identify
them.

This is not terribly obvious from a cursory read of the spec because of our
defaulting rules, that will automatically map {message label} to "In" or
"Out" for the MEPs we define, so it looks to the casual user like the
<input> is causing {message label} = "In" when in fact what's happening
under the covers is a little more sophisticated and general-purpose.

Jonathan Marsh - http://www.wso2.com - http://auburnmarshes.spaces.live.com
 
> -----Original Message-----
> From: Amelia A Lewis [mailto:[email protected]]
> Sent: Thursday, December 21, 2006 2:58 PM
> To: Paul Cotton
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: Re: Comment on Fragment Identifiers
> 
> Not replying for the group, but I believe that I understand the question
> and the mistaken assumption within it.  :-)
> 
> On Thu, 21 Dec 2006 14:44:42 -0800
> Paul Cotton <[email protected]> wrote:
> >We are wondering why the designators use "in" and "our" given that the
> >actual WSDL message labels are "input" and "output"?
> 
> In fact, we do not use "in" or "out".  We use the messageLabel specified
> in the message exchange pattern.  In part two, all of the message labels
> in all of the message exchange patterns are restricted to the set "In" and
> "Out" (note capitalization).  In the particular example cited, which
> relies on the in-out pattern, there are two messages, one labelled "In"
> and one labelled "Out".
> 
> "input" and "output" are nowhere used as message labels.  They are the
> local names of element information items in the WSDL 2.0 syntax.  These
> element information items are not referenced in the syntax of component
> designators, although as a class, they can be identified with the
> combination of .interfaceMessageReference() with their unique identifiers
> (ticketAgent/reserveFlight/In and ticketAgent/reserveFlight/Out in the
> example).
> 
> >Was this a conscious decision of the WSDL WG?
> 
> Yes.  There may be more than one [input] element information item or more
> than one [output] element information item in an interface operation in a
> valid WSDL, but all of the {messageLabel} properties of all of the
> {interfaceMessageReference} components of an interface operation MUST be
> unique.
> 
> >This apparent discrepancy can be seen in the examples in Appendix C.2
> >of the WSDL 2.0 Candidate Recommendation [1].
> >[1] http://www.w3.org/TR/2006/CR-wsdl20-20060327/#Iri-ref-ex
> 
> I hope that the above explanation clarifies matters.  It may behoove us to
> make some sort of explanation of this sort publicly available, as it
> appears to be on its way to being a FAQ.
> 
> Amy!
> --
> Amelia A. Lewis
> Senior Architect
> TIBCO/Extensibility, Inc.
> [email protected]