Proposal:
Change the sentences in section 2.1.1 which
currently reads:
3.
Stub Reference. [SBPEL2012] If neither [SBPEL2010]
nor [SBPEL2011] apply
and the analysis of the process
determines that the first use of the partner link by any activity is in
an <assign>
activity that sets the partner role, then the
multiplicity MUST be "0..1" and
the attribute wiredByImpl
MUST be set to "true".
to instead read:
3.
Stub Reference. [SBPEL2012]
If [SBPEL2010] does not
apply and the partner link has initializePartnerRole="no",
then the multiplicity MUST be "0..1"
and the attribute
wiredByImpl
MUST be set to "true".
Note that (4), which
follows this,
will turn any other partnerLink into a reference with multiplicity of
0..1 (not
wiredByImpl).
Michael
-----Original Message-----
From: Anish Karmarkar [mailto:Anish.Karmarkar@oracle.com]
Sent: Thursday, August 06, 2009 3:39 PM
To: OASIS BPEL
Subject: [sca-bpel] [Issue 53] BPEL Process: References with
Multiplicity 0..1
- how are they supposed to work?
This is now issue 53
http://osoa.org/jira/browse/BPEL-53
Mike Edwards wrote:
>
>
Raiser:
Mike Edwards
>
>
Target:
>
> Description:
>
>
> Multi-valued references (ie 0..n and
1..n) are
discussed in the
> specification at some length,
particularly in
section
> 3.2. Unfortunately, the case of 0..1
references is mentioned only in
> passing, although it has some significant
> matters that need discussion and
clarification.
>
> Section 2.1.1 makes it clear that 0..1
multiplicity
references do exist
> for BPEL processes.
>
> Basically, it states that where a
partnerLink is
determined to be a
> reference, it will be 0..1 if
@initializePartnerRole="no"
> OR @initializePartnerRole is omitted.
It must
also be the case that the
> partnerLink must not have its "first
use"
as the
> target of an <assign/> operation.
>
> Now, reading the BPEL 2.0 specification:
>
>
@initializePartnerRole="no" means that the BPEL Processor MUST NOT
> initialize the partnerLink variable.
>
> @initializePartnerRole omitted
means that the BPEL Processor MAY
> initialize the partnerLink variable.
>
>
> Now, the problems are these:
>
> A) If the partnerLink is NOT
initialized, then
it is essential that it
> is initialized by the BPEL process
itself, since any
> attempt to use that partnerLink variable
will
otherwise result in a fault.
>
> So, if the partnerLink is marked
@initializePartnerRole="no", the
> partnerLink must be supplied with a
value - but
> how is such a value supplied to the BPEL
process by
SCA? The SCA BPEL
> spec talks about the way in which
> serviceReferences are supplied in a
variable typed
as a
> serviceReferenceList for multi-valued
references.
> There is no such equivalent for 0..1
references.
>
> Even if the partnerLink is not marked
with
@initializePartnerRole at
> all, it is STILL possible for the
partnerLink to
> be uninitialized and so unusable without
being
assigned a value by the
> BPEL process - this is the result of that
> "MAY" in the BPEL 2.0 spec, listed
above. Again, there is no means by
> which the BPEL process can get a
> serviceReference to assign into the
partnerLink.
>
>
> B) If the partnerLink IS initialized,
how can the
BPEL process determine
> the difference between the case where the
> reference is wired and the case where
the reference
is unwired?
>
> There is no standard means for doing
this in BPEL.
>
> So, I think we may have a problem with
0..1
references in the SCA BPEL
> spec.
>
> Proposal:
>
> None
>
>
> 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: mike_edwards@uk.ibm.com
>
>
>
------------------------------------------------------------------------
>
> /
> /
>
> /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/
>
>
>
>
>
>
---------------------------------------------------------------------
To unsubscribe from this mail list, you must
leave the
OASIS TC that
generates this mail. Follow this link to all
your
TCs in OASIS at:
https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php