Re: [wsbpel] Issue - 52 - Proposal For Vote

["Yaron Y. Goland" <ygoland@bea.com>]

The problem with this approach is that the copied EPR contains very 
specific information about how communication is supposed to occur. For 
example it could say things like "Send the message via SOAP over UDP 
using WS-Security with a Kerberos Key and make sure to route it through 
our high security firewall."

If a process was interested in testing its communication path then 
copying the EPR and having the message be transmitted following the 
EPR's instructions makes sense. But if a process really just wanted to 
deliver a message to itself requiring that message to go through all the 
hoops outlined in the EPR isn't appropriate.

This kind of misunderstanding is typical when one tries to implement a 
feature as a side effect rather than declaratively. That is, the goal of 
the code you give below is to allow a process to talk to itself but 
rather than just stating that outright (which is what partnerIsSelf 
does) the effect is achieved through a side effect of copying the EPR. 
But that then introduces the complexities I describe above.

I also don't believe that IPC is anymore deadlock prone than business 
process web services are. If we don't like IPC maybe we should also get 
rid of Web Services? :)

		Yaron

Dieter Koenig1 wrote:
> 
> 
> 
> 
> If one *really* chooses to model a process like this, it can be done
> already:
>    assign-copy from partnerLink "myself-inbound" (myRole) to
> "myself-outbound" (partnerRole)
>    invoke (use partnerLink "myself-outbound" and a correlation set to get
> the same instance)
>    receive (use partnerLink "myself-inbound" and a correlation set to get
> the same instance)
> 
> In addition, imo, we should not introduce a dedicated construct which
> encourages intra-process-instance communication patterns that are asking
> for deadlocks.
> 
> Kind Regards
> DK
> 
> 
> 
>                                                                           
>              "Yaron Y. Goland"                                            
>              <ygoland@bea.com>                                            
>                                                                         To
>              16.09.2004 03:05          wsbpeltc                           
>                                        <wsbpel@lists.oasis-open.org>      
>                                                                         cc
>              Please respond to                                            
>                   ygoland                                          Subject
>                                        [wsbpel] Issue - 52 - Proposal For 
>                                        Vote                               
>                                                                           
>                                                                           
>                                                                           
>                                                                           
>                                                                           
>                                                                           
> 
> 
> 
> 
> In section 6.2, 7.2
> Change the partnerLink schema to:
> 
> <partnerLinks>
>        <partnerLink name="ncname" partnerLinkType="qname"
>             myRole="ncname"? partnerRole="ncname"?
>             partnerIsSelf="Boolean"?>+
>        </partnerLink>
> </partnerLinks>
> 
> Add the following text to the end of section 7.2:
> 
> If the partnerIsSelf attribute is set to true then it indicates that the
> partnerRole points to the BPEL process instance in which the partnerLink
> is being used. The default value of the partnerIsSelf attribute is
> false. partnerIsSelf is used to support internal communication so that a
> BPEL process instance can send messages to itself. By specifying
> partnerIsSelf="true" the BPEL engine knows that it is to provide a
> binding for the partnerRole that points at the BPEL process instance.
> 
> Add the following to the schema definition of tPartnerLink:
> <attribute name="partnerIsSelf" type="bpws:tBoolean" use="optional"
> default="no"/>
> 
> To unsubscribe from this mailing list (and be removed from the roster of
> the OASIS TC), go to
> http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php 
> 
> .
> 
> 
> 
> 
> To unsubscribe from this mailing list (and be removed from the roster of 
> the OASIS TC), go to 
> http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php. 
> 
>