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RE: Comment on Fragment Identifiers

From: David Orchard <dorchard@bea.com>
Date: Thu, 21 Dec 2006 17:27:06 -0800
Message-ID: <E16EB59B8AEDF445B644617E3C1B3C9C02E3BE39@repbex01.amer.bea.com>
To: "Jonathan Marsh" <jonathan@wso2.com>, "Amelia A Lewis" <alewis@tibco.com>, "Paul Cotton" <Paul.Cotton@microsoft.com>
Cc: <public-ws-policy@w3.org>, <ashok.malhotra@oracle.com>, <www-ws-desc@w3.org>

Ah, very very interesting.  I for one had forgotten that the meps had
in|out as component names rather than the syntax local names of input
and output.  

Now just to confirm my understanding.  If the wsdl meps are used, they
have no multiple messages in a single direction so component names are
sufficient and they are used as the message labels.  If different meps
are used, particularly a mep that has multiple messages in a single
direction, then each message will have a unique message label and that
will be used.  

I think that WSDL-only processing can still generate and evaluate the
component identifiers because the extensibility point is only in the #
of messages, not in the component names.  

Cheers,
Davce

> -----Original Message-----
> From: Jonathan Marsh [mailto:jonathan@wso2.com] 
> Sent: Thursday, December 21, 2006 4:06 PM
> To: 'Amelia A Lewis'; 'Paul Cotton'
> Cc: public-ws-policy@w3.org; ashok.malhotra@oracle.com; David 
> Orchard; www-ws-desc@w3.org
> Subject: 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:alewis@tibco.com]
> > Sent: Thursday, December 21, 2006 2:58 PM
> > To: Paul Cotton
> > Cc: jonathan@wso2.com; public-ws-policy@w3.org; 
> > ashok.malhotra@oracle.com; dorchard@bea.com; www-ws-desc@w3.org
> > 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 <Paul.Cotton@microsoft.com> 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.
> > alewis@tibco.com
> 
> 
Received on Friday, 22 December 2006 01:29:18 GMT

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