Re: [sca-bpel] [NEW ISSUE] Need to add Capability to indicate that aPartnerLink should be ignored when introspecting the ComponentType of aBPEL Process

Folks,

I mostly agree with Danny, but there
is one part of the email to be wary of:

" If the pL
is never used as a service, and the reference (EPR) is always assigned
into it (from another pL, from a vbl, from ...) then any external wiring
that would be applied will ALWAYS be ignored. "

...but note that multiplicity 0..n and
1..n partnerLinks ALWAYS look like this - and they must be taken account
of in the component type introspection.

OK, there is added (SCA) metadata to
make this plain, but it is the case.

Yours,  Mike.

Strategist - Emerging Technologies, SCA & SDO.

Co Chair OASIS SCA Assembly TC.

IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.

Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431  

Email:  

From:
Danny van der Rijn <>

To:
Dieter Koenig1 <>

Cc:
Mike Edwards/UK/IBM@IBMGB, OASIS BPEL
<>

Date:
08/09/2009 18:20

Subject:
Re: [sca-bpel] [NEW ISSUE] Need to add
Capability to indicate that a PartnerLink should be ignored when introspecting
the ComponentType of a BPEL Process

Dieter - 

It's a statement that not all pL's that are used in a BPEL process should
be wired.  Whether this translates to all of Mike's verbiage, or not,
for me, the salient part is:

"where it is a reference and the reference target/EPR
is assigned to it ..."

In my own words - If the pL is never used as a service, and the reference
(EPR) is always assigned into it (from another pL, from a vbl, from ...)
then any external wiring that would be applied will ALWAYS be ignored.
 We wouldn't want the burden of determining this case to fall to introspection,
so we would, instead, introduce an attribute for the author to include,
saying that this pL should not contribute to the componentType.

Now if it is used incorrectly, then perhaps you would get a runtime exception
if you tried to use it (as either a service or a reference), and this could
possibly get some static analysis help to point this out to you.  Such
a case could argue against including such an attribute, or it could point
to suggesting or requiring such static analysis.  IMO, the way to
go is to include the attribute without anything additional.

Danny van der Rijn

Dieter Koenig1 wrote: 

Hi Mike, why do you say "logically it represents the
same partnerLink

reference as the partnerLink in the outer scope"?

>From a BPEL perspective, the two partner links are independent (besides
the

fact that only one is visible at any point in the process definition).

IMO we introduced the "_" naming conventions precisely for this
situation.

As a result, I do not think that "only one (reference) is called for".

Kind Regards

Dieter König

Senior Technical Staff Member, WebSphere Process Server Architect

IBM Software Group, Application and Integration Middleware Software

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  From:       Mike Edwards <>
                     
                     
                     
     

                    
                     
                     
                     
                     
               

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  Date:       07.09.2009 14:42      
                     
                     
                     
                     

                    
                     
                     
                     
                     
               

  Subject:    [sca-bpel] [NEW ISSUE] Need to add Capability
to indicate that a PartnerLink should be ignored when      
    

              introspecting the ComponentType
of a BPEL Process                
                     
                     

                    
                     
                     
                     
                     
               

Raiser:                  
     Mike Edwards

Target:                  
     sca-bpel-1.1-spec-cd02.doc

Description:

Currently, any declaration of a partnerLink within a BPEL process results

in a <service/> or a <reference/> appearing in the componentType
of the

BPEL process.

This is not desirable in all circumstances:

- it may be that a BPEL process is written with an inner loop, where the

inner loop is implemented as a nested <scope/>.  In this inner
loop, it may

be that a partnerLink is declared within the nested scope and used purely

as a "local variable" within the loop, for example where it is
a reference

and the reference target/EPR is assigned to it from the contents of a

variable held in an outer scope.

In these circumstances, the partnerLink in the inner loop is shadowing
a

partnerLink in the outer scope - logically it represents the same

partnerLink

reference as the partnerLink in the outer scope.

At present, SCA cannot handle a situation such as this - the inner

partnerLink is introspected as a <reference/> and so is the outer

partnerLink - this

means 2 references appear when only one is called for.

To change this, it is necessary to provide a capability for the writer
of a

BPEL process to indicate that a given partnerLink should NOT be used

to introspect a <service/> or a <reference/> in the componentType.

Proposal:

Add a new SCA BPEL extension attribute that can be used to annotate a

<partnerLink/> element.

@skip

boolean - default value is false

When @skip="true", the <partnerLink/> element is ignored
when introspecting

the compoenntType of the BPEL Process.

The changes are shown in this marked up version of CD02, where the changes

are in Section 3.3 and Appendix A.

Yours,  Mike.

Strategist - Emerging Technologies, SCA & SDO.

Co Chair OASIS SCA Assembly TC.

IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.

Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431

Email:  

Unless stated otherwise above:

IBM United Kingdom Limited - Registered in England and Wales with number

741598.

Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU

[attachment "sca-bpel-1.1-spec-cd02+skip_proposal.doc" deleted
by Dieter

Koenig1/Germany/IBM]

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