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MEP and Operations

From: FABLET Youenn <fablet@crf.canon.fr>
Date: Thu, 13 Jun 2002 11:47:32 +0200
Message-ID: <3D086A34.4020305@crf.canon.fr>
To: Web Services Description mailing list <www-ws-desc@w3.org>

A few words about MEP and operations.

Let's have an operation that takes as input a date and a country name. 
As output, you get the size of the population of this country at that date.
IMO, the definition of this operation  should not change whether:
    - you receive the date and country name as one message or two 
separate messages
    - you send the output to the requester A, to another node B or both 
A and B.

The relationship between MEP and operations is somehow confusing because 
of the use of the term "message"  in the operation definition.
At now we have a syntax like:
        <input message="dateAndCountryName"/>.
I would much prefer to have an operation defined with a different term 
like "dataset" for instance,
        <input dataset="dateAndCountryName"/>
or allow to have multiple input elements in an operation:
         <input name="date" type="date_type"/>
         <input name="countryName" type="countryName_type"/>

An operation can then be mapped to one or more MEP (Get, 
Request-Response, Request-ResponseAndForward...). It will define the 
"real" messages to be received/sent and what you will find in each message.

Each (operation+MEP) can then be related to one or more protocols (wire 
format).

IMO, we should be able to define in WSDL the MEP we want to use for a 
particular operation.
Because MEP are protocol-generic, we should uncouple them from protocols.
Uncouple operations from MEP is also a good thing because an operation 
should not have different behaviours whether implemented with MEP A or 
MEP B.

Comments welcome,

   Youenn
Received on Thursday, 13 June 2002 05:48:15 GMT

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