RE: Use case

Assaf

I like your use case, but I think you are describing an orchestration rather
than a choreography. Is that correct?

David

-----Original Message-----
From: Assaf Arkin [mailto:arkin@intalio.com]
Sent: Tuesday, March 18, 2003 1:03 AM
To: public-ws-chor@w3.org
Subject: Use case



I would like to submit a use case based on one of the implementations I 
have reviewed. This use case is interesting since it highlights how one 
would use Web services technologies like WSDL, WS-Policy, SAML and 
WS-Choreography even for interactions that are not SOAP enabled.


Supply Acme Co. has an automated system for fulfilling orders. The 
supplier works with some customers that have an automated procurement 
system and both use SOAP to conduct transactions electronically. 
However, some customers have not automated their system. Acme Co. would 
like to conduct business with these customers and do so in an automated 
fashion.

Acme Co. develops a Web-based front end system for these customers using 
HTTP and HTML technologies. Customers log into the system using their 
customer identifier and are able to place orders, track their status and 
print out invoices. Acme Co. also has a helpdesk which allows customers 
to conduct transactions offline. A customer may send an order by fax, or 
call to check the order status, and an Acme Co representative would use 
the Web-based front end system to perform an online operation on their 
behalf.

Acme Co would like to have one definition for all transactions involving 
its customers regardless of technology. The business semantics are 
identical whether information is exchanged using SOAP, through the 
Web-based front-end or with the help of a representative. Acme Co 
realizes that reducing the number of business processes it needs to 
support would improve its efficiency.

Acme Co choses the proxy approach. It defines a single choreography that 
would be used for all transactions with its customers. The choreography 
is expressed in the form of WSDL operations that are performed by its 
order fulfillment service and the customer's procurement service. 
Protocol bindings and service end-points are defined for those customers 
that use SOAP. The Web-based front end and helpdesk systems are defined 
as services that implement the role of a procurement system as defined 
by the customer process in that choreography. In this particular case it 
uses SOAP to communicate with fulfillment system.

Although the Web-based front end is running in the same environment as 
the order fulfillment service, it is considered to be a customer 
service. When it exchanges messages it uses the security credentials 
given to the customer and not those of Acme Co to prevent one customer 
from learning about orders belonging to other customers.

This distinction is important. From a technological perspective both 
Acme Co's and the customer's service run in the same domain of control. 
However, from a business perspective these are two different domains of 
controls, and customers are identified as different non-overlapping 
domains of control. Acme Co manages its policy with regards to each 
customer in a uniform manner regardless of which technology is used to 
conduct the transaction or how far SOAP messages have to travel.

Once completed, Acme Co has:

- A uniform representation of the choreography between its fulfillment 
service the the customer procurement service
- A single business process to maintain
- The means to support customers that do not have automated processes 
using the uniform model
- A mechanism to support its security policies regardless of "location" 
of the customer service

arkin

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

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