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RE: i0001: EPRs as identifiers

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Thu, 25 Nov 2004 05:37:33 -0800
Message-ID: <DD35CC66F54D8248B6E04232892B63380413FEF8@RED-MSG-43.redmond.corp.microsoft.com>
To: "David Booth" <dbooth@w3.org>
Cc: "Francisco Curbera" <curbera@us.ibm.com>, "David Orchard" <dorchard@bea.com>, <public-ws-addressing@w3.org>


> -----Original Message-----
> From: David Booth [mailto:dbooth@w3.org] 
> Sent: 25 November 2004 01:50
> To: Martin Gudgin
> Cc: Francisco Curbera; David Orchard; public-ws-addressing@w3.org
> Subject: RE: i0001: EPRs as identifiers
> On Wed, 2004-11-24 at 15:00, Martin Gudgin wrote:
> . . .
> > > In other words, the use of different customerKeys (or 
> even different
> > > policies) does not adequately *motivate* the need for Reference
> > > Properties.  It would be far more instructive to use an 
> example that
> > > logically requires a different interface.
> > 
> > Why? Reference properties can be used to distinguish 
> between services
> > that differ by something other than interface/porttype...
> Of course they *can*.  But the point of a motivating example 
> is to show
> that the proposed solution is *necessary* -- not that it is
> *possible*.   If the problem could just as well be solved using other
> approaches (such as Reference *Parameters* or merely URIs) 
> then the need
> for the proposed solution has not been demonstrated.

I don't believe I have ever claimed that endpoints with different
porttypes/security requirements/etc. could not be distinguished by URI.
Obviously they can. However, I will repeat that we think that, in SOAP
based systems, being able to distinguish between such endpoints using
SOAP headers is also useful. I am not trying to force people that wants
to use URIs to distinguish between such services to use SOAP headers
instead. I'm happy for them to use URIs. But I equally don't want to
force someone who DOES want to distinguish between such endpoints using
SOAP headers from doing so.

Regarding necessity, one could argue that XML is not *necessary* as we
could just agree on ad-hoc formats for every exchange. High-level
programming languages are not *necessary* as we could all program in
assembly language or raw hex (perhaps some on this list still do... ).


> It's far more compelling to say that S1 and S2 should be externally
> viewed as different services (and thus should have different Web
> resource identifiers) if they have different *interfaces* than if they
> merely differ in the value of some policy or other input parameter.
> -- 
> David Booth
> W3C Fellow / Hewlett-Packard
Received on Thursday, 25 November 2004 13:37:48 UTC

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