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Re: Draft wording for targetResource attribute

From: David Booth <dbooth@w3.org>
Date: Tue, 10 Jun 2003 19:33:05 -0400
Message-Id: <5.1.0.14.2.20030610174802.02188aa0@localhost>
To: Jacek Kopecky <jacek@systinet.com>
Cc: WS-Description WG <www-ws-desc@w3.org>

Jacek,

Sorry I neglected to specifically address this in my previous message.

I am assuming in your example that you meant the services to use the same 
targetNamespace.  If so, it seems to me that (normally) you would already 
have that kind of semantic equivalence, since the targetNamespace 
indentifies the intended semantics[3].  However, in the end, it will always 
depend on how the semantics of that particular service are defined, which 
is outside of our scope to define.

For example:

<definitions targetNamespace="n" ...>
   . . .
   <service name="a" interface="i" targetResource="foo">
    <port name="x">...</port>
   </service>
</definitions>

<definitions targetNamespace="n" ...>
   . . .
   <service name="b" interface="i" targetResource="foo">
    <port name="y">...</port>
   </service>
</definitions>

Both services indicate the same targetNamespace ("n"), which is supposed to 
unambiguously identify the semantics of the terms used in that 
namespace[3].  Since service "a" and service "b" also indicate the same 
WSDL interface ("i"), then it would be natural to make them semantically 
equivalent, and doing so might be recommended "best practice".  But since 
the semantics of the service are beyond the scope of the WSDL 
specification, they COULD be defined differently.

In other words, it may be a good idea to make them equivalent in most 
cases, and that may be a good thing to recommend as a "best practice", but 
since the semantics of a service are not defined by the WSDL specification, 
I don't think it's something that the WSDL specification can meaningfully 
require.

1. WSDL 1.2 draft: 
http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl12/wsdl12.html#Service_resource_attribute

2. TAG Web Arch: http://www.w3.org/TR/webarch/#representations

3. targetNamespace: 
http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl12/wsdl12.html#Definitions_XMLRep

4. Resource definition: http://www.ietf.org/rfc/rfc2396.txt


At 02:02 PM 6/10/2003 +0200, Jacek Kopecky wrote:
>David,
>
>I've fought on one telcon for the wording, whatever it ends up being, to
>include the following explanation (not necessarily in the same words):
>
>Different ports in two services with the same interface and the same
>targetResource are interchangeable in the same sense as different ports
>within one service with that interface and targetResource. I.e. from the
>point of view of the ports, it doesn't really matter if I write
>
><service name="a" interface="i" targetResource="foo">
>    <port name="x">...</port>
></service>
><service name="b" interface="i" targetResource="foo">
>    <port name="y">...</port>
></service>
>
>or
>
><service name="c" interface="i" targetResource="foo">
>    <port name="x">...</port>
>    <port name="y">...</port>
></service>
>
>It seemed to me that there was general agreement to this.
>
>Best regards,
>
>                    Jacek Kopecky
>
>                    Senior Architect
>                    Systinet Corporation
>                    http://www.systinet.com/

-- 
David Booth
W3C Fellow / Hewlett-Packard
Telephone: +1.617.253.1273
Received on Tuesday, 10 June 2003 19:33:10 GMT

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