[sca-bpel] New Issue - References to WS-BPEL 2.0 <partnerLink> Attributes "myRole" and"partnerRole"

[Dieter Koenig1 <dieterkoenig@de.ibm.com>]

Target: SCA-BPEL 1.1 - Committee Draft 02 and Public Review Draft 0

Description: In the April 23 TC call, I mentioned a potential problem
w.r.t. referencing the WS-BPEL 2.0 <partnerLink> attributes myRole and
partnerRole in SCA-BPEL normative statements, and took an action item for
investigating the situation in (1) the SCA-BPEL specification and (2) the
test assertion document.

Background: In WS-BPEL 2.0, the specification of the @myRole and
@partnerRole attributes of a <bpel:partnerLink> element is optional:
   "Within a <partnerLink>, the role of the business process itself is
   indicated by the attribute myRole and the role of the partner is
   indicated by the attribute partnerRole. When a partnerLinkType has only
   one role, one of these attributes is omitted as appropriate. [SA00016]
   Note that a <partnerLink> MUST specify the myRole, or the partnerRole,
   or both. This syntactic constraint MUST be statically enforced."
(Reference: http://docs.oasis-open.org/wsbpel/2.0/wsbpel-v2.0.html, section
6.2. Partner Links).

In other words, if there is a two-role partner link type, it is sufficient
for the <partnerLink> to specify **only one** of the @myRole / @partnerRole
attributes because the other one is implied.

As a result, there may be situations with two-role partner link types where
SCA-BPEL mentions a @partnerRole attribute while the <bpel:partnerLink>
element only contains a @myRole attribute, or vice versa.

I checked the normative statements in SCA-BPEL 1.1:

   [SBPEL2015] The WSDL port type in the <interface.wsdl> declaration for
   the service in the introspected component type MUST be the same as the
   port type of the myRole of the partner link.
   [SBPEL2016] If the partner link type has two roles, then the
   <interface.wsdl> declaration MUST also have a @callbackInterface
   attribute whose value points to the same WSDL port type as the
   partnerRole of the partner link.
   [SBPEL2017] The WSDL port type in the <interface.wsdl> declaration for
   the reference MUST be the same as the port type of the partnerRole of
   the partner link.
   [SBPEL2018] If the partner link type has two roles, then the
   <interface.wsdl> declaration MUST also have a @callbackInterface
   attribute whose value points to the same WSDL port type as the myRole of
   the partner link.
   [SBPEL3011] The partnerLinkType and partnerRole attributes of the
   partner link and multi-valued reference variable MUST be matched.
   [SBPEL3012] There MUST be at least one code-path where the values from
   the multi-valued reference variable are copied to the partnerRole of the
   partner link.

The rule [SBPEL3011] explicitly refers to the "partnerRole attribute" (so
it has the problem mentioned above).

The other rules only talk about the "myRole" or "partnerRole" (which
**can** be interpreted in an abstract way and not as the name of an
existing attribute), so we may leave that as-is.

Proposal:

(1) As a minimal-invasive change, I suggest changing [SBPEL3011] as follows
in order to avoid the explicit reference of the "partnerRole" attribute of
a <partnerLink> element (which may not be present):

   [SBPEL3011] The partnerLinkType attribute of the partner link and
   multi-valued reference variable MUST be matched and the partnerRole
   attribute of the multi-valued reference variable MUST match the
   partnerRole of the partner link.

(2) The test assertions SBL-TA-2014 and SBL-TA-2015 should be changed as
well. In the same way as the SCA-BPEL spec statements, they should say
"myRole" instead of "@myRole attribute" and "partnerRole" instead of
"@partnerRole attribute".

Kind Regards

Dieter K�nig

Senior Technical Staff Member, WebSphere Process Server Architect
IBM Software Group, Application and Integration Middleware Software
WSS Business Process Solutions
                                                                       
                                                                       
                                                                       
                                                                       
                                                                       
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