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Clarification of CDL - Issue CET-01 sought

From: Steve Ross-Talbot <steve@enigmatec.net>
Date: Mon, 14 Jun 2004 19:28:07 +0100
Message-Id: <955AB96E-BE30-11D8-B1C5-000393D13C9A@enigmatec.net>
To: WS-Choreography List <public-ws-chor@w3.org>

Issue CET-01. What happens if you get an error in a Work Unit that is 
within an Exception Block?

An exception block is defined as:

  <exception  name="ncname">
             WorkUnit-Notation+
   </exception>?
   <finalizer  name="ncname">
           WorkUnit-Notation
   </finalizer>?

Where a WorkUnit-Notation is defined as:

<workunit  name="ncname"
       guard="xsd:boolean XPath-expression"?
       repeat="xsd:boolean XPath-expression"?
       block="true|false" >
       Activity-Notation
</workunit>

And Activity-Notation as:
<start>
Activities are the lowest level components of the Choreography, used to 
perform the actual work.

  An Activity-Notation is then either:
	• 	A Ordering Structure which combines Activities with other Ordering 
Structures in a nested way to specify the ordering rules of activities 
within the Choreography
	• 	A WorkUnit-Notation
	• 	A Basic Activity that performs the actual work. These are:
		◦ 	Interaction, which results in exchange of messages between 
participants and possible synchronization of their states and the 
actual values of the exchanged information
		◦ 	A Perform, which means that a complete, separately defined 
Choreography is performed
		◦ 	An Assign, which assigns, within one Role, the value of one 
Variable to the value of a Variable
		◦ 	No Action, which means that the Choreography should take no 
particular action at that point
<start\>

Thus there is nothing to suggest that an Exception Block can have an 
Exception Block defined inside of it.
First of all is this correct?

Secondly exceptions are tagged alternate paths are they not? That is 
they do not necessarily carry the same semantics as a try/catch block 
in Java (no stack unwinding since there is no stack because it is a 
description).
Received on Monday, 14 June 2004 14:28:26 UTC

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