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Re: BurdettML comments

From: Jon Dart <jdart@tibco.com>
Date: Wed, 25 Jun 2003 09:56:15 -0700
Message-ID: <3EF9D42F.10804@tibco.com>
To: "Burdett David" <david.burdett@commerceone.com>
CC: "'public-ws-chor@w3.org '" <public-ws-chor@w3.org>

Burdett, David wrote:

> Also in my spec I assumed that an Interaction was implmented by a single
> message (ignoring signals) sent from one role to another. In your example
> for "DoLogin" to succeed, you would need two messages the LoginRequest from
> the client to the server and the LoginResponse from the server to the
> client. The result could be either succeed or fail.

One issue here for me is how this maps into the SOAP/WSDL layer (if 
there is one). The simple way to implement login is with a request/reply 
MEP. Then there are two messages, as you suggest, but it is one 
operation, in the WSDL sense of the term. Maybe it should be possible to 
include such a MEP in the choreography without explicitly showing the 
two messages - it is a logical unit.

Generally, I am concerned about duplicating WSDL layer information into 
the choreography layer. When you have duplication you also have the 
possibility for the information to get out of sync.

Also re failure: if you are using SOAP, the WSDL tells you if a fault 
condition is possible. If this fault leads to a state transition it may 
need to be handled explicitly in the choreography. But perhaps there 
should be a default behavior (termination of the choreography?). Also 
something like the BPEL concept of fault handlers may be necessary. 
There is no equivalent concept in BurdettML, AFAIK.

--Jon
Received on Wednesday, 25 June 2003 12:56:23 GMT

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