Re: [wsbpel] Issue - 32 - Link Semantics in Event Handlers

["Yuzo Fujishima" <fujishima@bc.jp.nec.com>]

Frank,

I am not sure whether I understand your question correctly.

My point was that something is not clearly defined anywhere
in the specification. So I couldn't point out where.

I think there are two interpreations for the link semantics:
A: link status is maintained per event handler thread.
B: link status is maintained per process instance.

Could you prove that only one of them is valid,
based on the information contained in the specification?

Yuzo

----- Original Message ----- 
From: "Frank Leymann" <LEY1@de.ibm.com>
To: <wsbpel@lists.oasis-open.org>
Sent: Sunday, July 06, 2003 1:01 AM
Subject: Re: [wsbpel] Issue - 32 - Link Semantics in Event Handlers


> 
> Would you please point out where the spec does allow two conflicting
> interpretations?
> 
> The intend of the spec was to allow the same <OnMessage> receiving multiple
> messages concurrently, in parallel (as soon as the associated scope has
> been entered.  Please see the corresponding quotes from the spec:
> 
> "The event handlers associated with a scope are enabled when the associated
> scope starts . "
> 
> "A message event occurs when the appropriate message is received on the
> specified partner link using the specified port type and operation.  When
> such an event occurs, the corresponding activity is carried out.  However,
> the event remains enabled, even for concurrent use.  Thus a particular
> message event can occur multiple times while the corresponding scope is
> active."
> 
> "All event handlers associated with a scope are disabled when the normal
> processing of the scope is complete.  The already dispatched event handlers
> are allowed to complete.  The completion of the scope as a whole is delayed
> until all active event handlers have completed."
> 
> Regards,
> Frank
> 
> -------------------
> Prof. Dr. Frank Leymann, Distinguished Engineer
> IBM Software Group
> Member, IBM Academy of Technology
> 
> Phone 1:  +49-7031-16 39 98
> Phone 2:  +49-7056-96 50 67
> Mobile:  +49-172-731 5858
> -----------------
> 
> 
> 
> 
> 
> To:    <wsbpel@lists.oasis-open.org>
> cc:
> Subject:    Re: [wsbpel] Issue - 32 - Link Semantics in Event Handlers
> 
> 
> Chunbo, Edwin
> 
> According to a messge from Satish,
> http://lists.oasis-open.org/archives/wsbpel/200305/msg00131.html
> Edwin's view seems to be closer to the original authors' intention.
> 
> The problem is that the specification itself allows at least two
> interpretations. I raised this issue to clarify which is the right one.
> After the discussion and the issue/requirementprocess mature,
> I probably propose a motion to pick one iterpretation.
> 
> Yuzo
> 
> 
> Chunbo> Hi Yuzo,
> Chunbo>
> Chunbo> I think the link status is maintained at process instance level,
> not based
> Chunbo> on the thread level.  So A and B will be synced as far as they
> belong to the
> Chunbo> same process instance.
> Chunbo>
> Chunbo> -Chunbo
> 
> Edwin> Yuzo,
> Edwin> Thank you for the example. It seems that in that specific case, each
> message
> Edwin> would create a new flow activity. So if you have 4  messages, you
> end up
> Edwin> with 4 instances of the flow activity (all running concurrently).
> Each flow
> Edwin> activity instance will have its own AtoB link. No?
> Edwin> Edwin
> 
> 
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