W3C home > Mailing lists > Public > public-ws-chor@w3.org > March 2005

Re: Issue 998 - State that sequential lexically ordering is the default for interpretation of CDL

From: Gary Brown <gary@enigmatec.net>
Date: Wed, 16 Mar 2005 17:05:12 -0000
Message-ID: <008101c52a4a$5518c3c0$0300a8c0@LATTITUDEGary>
To: "Tony Fletcher" <tony_fletcher@btopenworld.com>, <public-ws-chor@w3.org>
MessageHi Tony

I believe a workunit can only have one immediate child activity, so if you wanted more than one activity, you would need to place them inside a sequence, parallel or choice anyway.

Regards
Gary
  ----- Original Message ----- 
  From: Tony Fletcher 
  To: public-ws-chor@w3.org 
  Sent: Wednesday, March 16, 2005 2:32 PM
  Subject: Issue 998 - State that sequential lexically ordering is the default for interpretation of CDL


  Dear Colleagues,

  I was hoping to illustrate the point of this issue by taking some of the examples from the the specification directly, but unfortunately they are all a bit too simple in that they only have one activity in a series.  The point I am addressing comes into play when there is more than one activity in series in the choreography description not wrapped in an explicit SEQUENCE, PARALLEL or CHOICE construct, which is currently permitted.  So I have just taken a couple of partially filled out examples to illustrate the point.

  Are:
  <workunit  name="StockCheck" 

             guard="cdl:getVariable('StockQuantity','','"/Product/Qty"', 

                                    '"tns:Retailer") > 10')"            

             block="false" >

     ... <!--some activity -->

     ... <!--some other activity -->

  </workunit>

   
  and 
  <workunit  name="StockCheck" 

             guard="cdl:getVariable('StockQuantity','','"/Product/Qty"', 

                                    '"tns:Retailer") > 10')"            

             block="false" >

     ... <!--some other activity -->

     ... <!--some activity -->

  </workunit>

  the same?  (Where typically 'some activity' would be an interaction and 'some other activity' would be a different interaction.)

  Another pseudo example:

  <workunit  name="StockCheck">

     ... <interaction name="1" ...>

     ... <interaction name="2" ...>

  </workunit>

  workunit  name="StockReplenish">

     ... <interaction name="3" ...>

  </workunit>

  and

  workunit  name="StockReplenish">

     ... <interaction name="3" ...>

  </workunit>

  <workunit  name="StockCheck">

     ... <interaction name="2" ...>

     ... <interaction name="1" ...>

  </workunit>



  I hope this makes the point clear  One solution is to include a default ordering statement in the specification as the issue suggests.  Another solution is to declare all of the above examples illegal CDL and state that when more than one activity is placed lexically next to another (and they do not have to be of the same type) then they MUST be wrapped with and explicit SEQUENCE, PARALLEL or CHOICE activity.



   Best Regards,

  Tony                           


       Tony Fletcher

        Technical Advisor 
        Choreology Ltd.
        68, Lombard Street, London EC3V 9L J   UK
       
        Phone:  
       +44 (0) 1473 729537
       
        Mobile: 
       +44 (0) 7801 948219
       
        Fax:    
       +44 (0) 870 7390077
       
        Web:
       www.choreology.com
       
        CohesionsT
       
        Business transaction management software for application coordination
       


        Work: tony.fletcher@choreology.com 
       
        Home: amfletcher@iee.org
       






image002.gif
(image/gif attachment: image002.gif)

Received on Wednesday, 16 March 2005 17:05:28 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Saturday, 18 December 2010 01:01:28 GMT