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Re: targetResource wording

From: Steve Tuecke <tuecke@mcs.anl.gov>
Date: Fri, 20 Jun 2003 08:49:08 -0500
Message-Id: <>
To: "David Booth" <dbooth@w3.org>
Cc: www-ws-desc@w3.org, Mark Baker <distobj@acm.org>, "Sanjiva Weerawarana" <sanjiva@watson.ibm.com>, "Champion, Mike" <Mike.Champion@SoftwareAG-USA.com>


Note that we had a very similar issue in OGSI (see section of [1]), 
and reached the same conclusion described by David.



At 02:14 PM 6/19/2003, David Booth wrote:

>It looks to me like there is some misconception of what the targetResource 
>means, partly (I think) because some of the statements in this discussion 
>have been a little imprecise.
>The targetResource attribute has nothing to do with describing a 
>service.  It is used to indicate a relationship *between* services.  Its 
>purpose is to allow two WSDL <service> descriptions, d1 and d2, to assert 
>that (behind the scenes) the services s1 and s2 that they describe are 
>actually "manipulating" the same resource.  In other words, if d1 and d2 
>both state "targetResource='u'", where u is some URI, then they have 
>asserted that s1 and s2 "manipulate" the resource r that is identified by 
>URI u.
>As we know from RFC2396[1], a resource can be anything -- a physical 
>object, an abstract concept -- anything.  So what does it mean to say that 
>s1 and s2 "manipulate" the same resource r?  Without knowing the semantics 
>of d1 and d2 you don't know.  That is not defined by the WSDL 1.2 
>specification.  (Nor should it be, IMO.)  Until you know the semantics of 
>d1 and d2, the only concrete thing you can conclude is that s1 and s2 are 
>somehow related to each other through r.
>(Just in case there is confusion about this, the "targetResource='u'" 
>attribute is NOT asserting that s1 and s2 are the same resource as each 
>other, nor is it asserting that s1 and s2 are the same resource as r.)
>Does this vagueness present a problem?  No.  Different applications will 
>know what they wish to do with this.  (The canonical example is a 
>printDocument service s1 and a managePrinter service s2, both manipulating 
>the same physical printer r.)  The reason the WG described the 
>targetResource as "manipulating" the same resource was to give users 
>guidance about its intended use, even though the precise meaning of the 
>word "manipulate" is impossible to nail down in this context.
>Regarding the name "targetResource", u does identify a resource, so the 
>"Resource" part of the name definitely is appropriate.  Furthermore, 
>proponents of the targetResource attribute like to think of r as being the 
>ultimate "target" of interactions with s1 or s2; hence the name 
>I hope this helps to clarify the situation.
>1. RFC2396: http://www.ietf.org/rfc/rfc2396.txt
>David Booth
>W3C Fellow / Hewlett-Packard
>Telephone: +1.617.253.1273
Received on Friday, 20 June 2003 09:49:56 UTC

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