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Re: Definition of Terms

From: Assaf Arkin <arkin@intalio.com>
Date: Tue, 25 Mar 2003 12:22:13 -0800
Message-ID: <3E80BA75.1030003@intalio.com>
To: edwink@collaxa.com
CC: "'WS Choreography (E-mail)'" <public-ws-chor@w3.org>

Edwin Khodabakchian wrote:

> Assaf,
>  
> I am not sure what the correct verb would be for choreography. It 
> seems to me that we want to highlight the contractual nature of the 
> choreography (more than the fact that his has a beginning and an end). 
> May be: an application/service *complies* with a role define in a 
> choreography. All I am recommending is that we do not use the same 
> term for choreography and orchestration.
>  
> I have one more question: Could you please help me understand what you 
> mean by "a choreography may involve multiple such conversions"? I am 
> trying to see how this sentence fits with a "conversation as an 
> instantiation of a choreography (similar to how an object is an 
> instance of a class)".
>  
> Thank you,
>  
> Edwin

When two participants talk to each other they engage in a conversation. 
All other participants are not necessarily aware of that conversation, 
when it does not involve them. So a multi-party choreography can express 
multiple conversations that are going on and overlapping with each 
other, by allowing a conversation to be scoped to a subset of the parties.

In fact, what a multi-party tries to do is express how multiple 
conversations are brought together in a larger context. It can express 
the causal dependency between these conversations and put a larger 
context in which such relationships can be depicted.

For example, the patient-receptionist-doctor (PRD) scenario involves 
three conversations and expresses the relationship between these 
conversations:

1. Patient-receptionist
2. Receptionist-doctor
3. Doctor-patient

These conversations do not follow each other: they are interleaved. The 
choreography starts and actuall ends in the scope of the 
patient-receptionist conversation (from hi to bye). The 
receptionist-doctor conversation starts before the doctor-patient but 
concludes after the doctor-patient (doctor notifies recipient it is now 
able to accept patients).

There are much easier means to express sequences of conversations, but 
the only one that can express interleaved conversations with dependency 
between these conversations, is the multi-party choreography,

arkin


-- 
"Those who can, do; those who can't, make screenshots"

----------------------------------------------------------------------
Assaf Arkin                                          arkin@intalio.com
Intalio Inc.                                           www.intalio.com
The Business Process Management Company                 (650) 577 4700


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Received on Tuesday, 25 March 2003 15:25:05 GMT

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