Re: [sca-bpel] ISSUE 42: SBPEL3004 has an incorrect 'MAY'.

[Mike Edwards <mike_edwards@uk.ibm.com>]

Danny,

Thanks for your investigative work.

I am happy with your proposal to remove
SPBEL3004 as a normative statement - but I would instead recommend replacing
it with a non-normative
explanatory sentence:

"In order to have an SCA multi-valued
reference in a WS-BPEL process, a variable is declared in the process which
uses the sca-bpel:multireference extension element"

To deal with the queries which you raise:

- Since partnerLinkTypes aren't QNames,
do we have to insist that the partnerLinkType attribute of the sca-bpel:multiReference
resolve to a partnerLinkType declared in the same scope?
<mje>partnerLinkTypes are QNames, so
I don't understand this comment. The following is from the WS-BPEL spec:</mje>
<xsd:attribute name="partnerLinkType"
type="xsd:QName" use="required" /> 

- Since we want the componentType derivation
to be deterministic, how do we determine whether it's 0..n or 1..n?
<mje>Doesn't a calculation similar
to that in section 2.1.1 apply?  I agree that we may need to add a
parallel section for the 0..n and 1..n cases..</mje>

- What does . [SBPEL3007] "The
type of the reference MUST be determined by the partner link type and the
partner role attributes of the sca-bpel:multiReference extension element."
mean?
<mje>The type of a BPEL reference is
actually defined by the porttype which applies to the reference, which
is found via the partnerLinkType and partnerRole
- do you think that this needs spelling out
further?</mje>

- Does 3006 as above need to be tightened
up to say that it's actually not "a reference" but "THE
reference pointed to by the partnerLinkType attribute"?
<mje>I think that 3006 is correct -
the partnerLinkType attribute does not point at an SCA reference - it points
at a partnerLinkType.
The existence of a <reference/> in
the componentType is derived from the presence of a variable with the sca-bpel:multireference
attribute,
which I what 3006 says. </mje>

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

From:	Danny van der Rijn <dannyv@tibco.com>
To:	sca-bpel@lists.oasis-open.org
Date:	14/05/2009 17:26
Subject:	Re: [sca-bpel] ISSUE 42: SBPEL3004 has an incorrect 'MAY'.

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On today's call, Mike Edwards proposed:

Replace the text of SBPEL3004 with: "To represent
an SCA multi-valued reference a WS-BPEL process MUST use a variable which
is declared with a sca-bpel:multiReference extension element."



I had some concerns with the statement that were at least
echoed by Sanjay.  I was thinking that we lift the style of the text
from SCA-BPEL 2001/2:

[SBPEL2001] If a partner link specifies a sca-bpel:service attribute, then a service MUST be generated for the introspected component type. [SBPEL2002] The name of the service MUST be the value of the sca-bpel:service attribute.

As I was looking at what replacement text I might use for 3004 or Mike Edwards statement, what I came across was actually the next sentences, SBPEL 3005/6:
When a variable declaration contains the sca-bpel:multiReference extension, the type of the variable MUST be an element of sca-bpel:serviceReferenceList.
...
[SBPEL3006] The introspected component type MUST include a reference with a multiplicity of either "0..n" or "1..n" that corresponds to a variable with the sca-bpel:multiReference element.

I

I propose that we simply delete SBPEL 3004.

Furthermore, I think there are some issues lurking elsewhere in this paragraph:

- Since partnerLinkTypes aren't QNames, do we have to insist that the partnerLinkType attribute of the sca-bpel:multiReference resolve to a partnerLinkType declared in the same scope?
- Since we want the componentType derivation to be deterministic, how do we determine whether it's 0..n or 1..n?
- What does . [SBPEL3007] "The type of the reference MUST be determined by the partner link type and the partner role attributes of the sca-bpel:multiReference extension element." mean?
- Does 3006 as above need to be tightened up to say that it's actually not "a reference" but "THE reference pointed to by the partnerLinkType attribute"?


Michael Rowley wrote:
http://www.osoa.org/jira/browse/BPEL-42
 
From: Najeeb Andrabi [mailto:nandrabi@tibco.com]
Sent: Friday, May 08, 2009 2:06 PM
To: sca-bpel@lists.oasis-open.org
Subject: [sca-bpel] NEW ISSUE: SBPEL3004 has an incorrect 'MAY'.
 
Title: SBPEL3004 has an incorrect 'MAY'.

Target: SCA BPEL C&I PR 01

Description:
SBPEL3004 states the following:
"In a WS-BPEL process definition, a variable MAY include an sca-bpel:multiReference extension element that declares that the variable represents a multi-valued reference."

'MAY' implies that some runtimes may choose not to implement multi-valued reference using sca:bpel:multiReference extension element. We want that the implementation of multi-valued reference using sca-bpel:multiReference extension element be portable across different runtimes.
 
Proposal:

Replace with --
"In a WS-BPEL process definition, a variable can include an sca-bpel:multiReference extension element that declares that the variable represents a multi-valued reference."
 

-Najeeb
 

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