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RE: Semantics in WSDL-S ?!

From: Battle, Steven Andrew <steve.battle@hp.com>
Date: Mon, 21 Nov 2005 11:28:41 -0000
Message-ID: <DE62D3D0BDEF184FBB5089C7D387C37449B742@sdcexc04.emea.cpqcorp.net>
To: "Shi, Xuan" <xshi@GEO.WVU.edu>
Cc: <public-sws-ig@w3.org>

> -----Original Message-----
> From: public-sws-ig-request@w3.org 
> [mailto:public-sws-ig-request@w3.org] On Behalf Of Shi, Xuan
> Sent: 21 November 2005 04:54
> To: 'jeff@inf.ed.ac.uk '; 'David Martin '
> Cc: 'Amit Sheth @ LSDIS '; 'public-sws-ig@w3.org '
> Subject: Semantics in WSDL-S ?!
> Importance: High
> 
> BTW, why is it said that "the current WSDL standard operates 
> at the syntactic level"?  What is any more semantic about the 
> things that are labelled "semantic"?
>
> 
> WSDL operates at the syntactic level because it only contains 
> the names of the object data types and functions, etc. that 
> are used developing the service, as well as the object 
> hierarchy, relations, etc. which are ALL of the outcomes 
> generated in Object Oriented Programming (OOP) approach. This 
> means, WSDL contains the details of coding process generated 
> by OOP, however, the meaning (semantics) of the service is 
> not described and defined within WSDL. 
> 
...
> 
> the meaning (semantics) of this Web service is:
> 
> if the requester can invoke ESRI's authentication Web service 
> to obtain a validated token string, then requester can use 
> this token string with the input "address" object data type 
> as well as the specified data source to invoke Address Finder 
> Web Service, which will then return the location(s) 
> (longitude and latitude) that can match the input address or 
> will then return an error message to the requester. 
>

Clearly, there's a lot you can't say in WSDL. What it does well is to
describe the service _signature_ in terms of the operations available
through one or more service interfaces. Like you say it doesn't capture
any of the 'meaning' as you describe above, which includes composition,
inputs and outputs (and their types). But this is a different question
as to whether it is 'semantic' or not. WSDL 2.0 now has an RDF mapping
that furnishes it with a model theory. You can think of a WSDL
description as a set of logical assertions (about a service interface).
This in itself is an _amazing_ thing and is a qualitative step-up from
the XML world view, but is about as 'semantic' as its ever going to get.


The real action is how you can extend this model to incorporate the more
dynamic aspects of the service that you're interested in. This is as
much about how to establish shared ontologies (of address, location,
errors) as figuring out how to add the right markup to the WSDL.

Steve.
Received on Monday, 21 November 2005 11:28:55 GMT

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