Re: [wsbpel] Issue - 75 - Do we need locally declared partnerLinks?

[Assaf Arkin <arkin@intalio.com>]

If I look at the spec right now and try to imagine how to achieve this 
behavior using global partner links, it requires a lot of variable 
shuffling which is both complex and error prone. There will be one 
myRole EPR and a lot of shuffling of the partnerRole EPRs in/out of 
locally scoped variables. I would value any solutions that brings 
simplicity and reduces the potential for errors.

Having locally scoped partner links where the partnerRole is the only 
thing that changes (myRole is fixed to the same EPR for all copies) 
would simplify process definitions by simply removing all the complexity 
of the variable shuffling that is currently required. That alone would 
be a welcome change in my opinion.

As for having unique myRole EPRs for each local copy of the partner 
link, there are indeed issues with that. It sounds to me like 
correlation sets (which can be local to a scope) are the way to go. So, 
assuming that all local copies of the same partner link have the same 
myRole EPR which can be fixed at deployment (no auto generation of 
listen points), do we have any problem adding locally declared partner 
links to the language?

Assaf

Satish Thatte wrote:

>I would not want to make myRole dynamic - dynamic (visible) listen
>points will take us in the direction of auto generation. This is the
>complication - copies of partnerLinks that need to stay consistent for
>myRole and dynamic for partnerRole. 
>
>-----Original Message-----
>From: Assaf Arkin [mailto:arkin@intalio.com] 
>Sent: Monday, November 17, 2003 7:37 AM
>To: Satish Thatte
>Cc: Frank Leymann; wsbpel@lists.oasis-open.org
>Subject: Re: [wsbpel] Issue - 75 - Do we need locally declared
>partnerLinks?
>
>Satish Thatte wrote:
>
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>>Assaf, if the issue was partnerLink visibility limited to a local scope
>>it would be trivial.  But that is the only situation where you can have
>>'each locally scoped partner link is assigned a unique endpoint
>>reference'.  All the examples I have seen justifying this idea also
>>require lifetime semantics, i.e., multiple copies of a locally scoped
>>partnerLink could exist, held, e.g., in corresponding compensation
>>handlers.  Now the situation becomes much more complex as Frank pointed
>>out earlier.
>> 
>>
>>    
>>
>Then let's try and tackle it.
>
>The spec already has to deal with lifetime semantics of locally scoped 
>variables and correlation sets. Let's assume that partner links are 
>another type of scoped variable accessed (read/write) like any other 
>locally or globally declared variable. That would cover the lifetime and
>
>access semantics. The spec also handles the case where multiple partner 
>links are based on the same partner link type. We can extend that to the
>
>myRole EPR of a locally declared partner link (i.e. unique EPR in each 
>scope).
>
>What other problems are we going to run into?
>
>arkin
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>>Satish
>> 
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>>
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