RE: [sca-bpel] Issue 11 - BPEL variable initialization and SCA properties

From
Martin Chapman <>
Date
2007-12-12T17:27:03+00:00
ID
007801c83ce4$4888e400$
Thread
RE: [sca-bpel] Issue 11 - BPEL variable initialization and SCA properties
Title: Message

Note 
the original Assembly spec did not use RFC2119 and one of the jobs of that TC is 
to re-write accordingly.

I 
think when we see a suggested change to rectify this in the Assembly 
Spec, we should raise a new issue there and proposal 
there.

 

Martin..

  

  
-----Original Message-----
From: Mark Ford 
  [mailto:] 
Sent: Wednesday, December 
  12, 2007 12:53 AM
To: 'Michael Rowley'; 'Alex Yiu'
Cc: 
  
Subject: RE: [sca-bpel] Issue 11 - 
  BPEL variable initialization and SCA properties

  
The mustSupply text from the assembly specification below 
  SHOULD use the capitalized words from RFC 2119. It would be better to say that 
  the default-property-value MUST NOT be provided when mustSupply="true". 
  

  
 

  
That said I think the treatment of BPEL variable 
  initialization should be the same regardless of the form of the from-spec. If 
  I understand your proposal, you would treat an expression from-spec 
  differently than a literal from-spec.

  
 

  
After reviewing the Assembly spec a little, I'm inclined 
  to suggest that any value from the component overrides the initialization 
  from-spec for the variable in the BPEL. This seems consistent with the goal of 
  allowing the configuration of an implementation with externally set data 
  values. (Section 6.1 of the Assembly spec). 

  
 

  
- Mark

  

  
  From: Michael Rowley [mailto:] 
  
Sent: Thursday, November 01, 2007 5:58 PM
To: Alex Yiu; 
  Mark Ford
Cc: 
Subject: RE: 
  [sca-bpel] Issue 11 - BPEL variable initialization and SCA 
  properties

  

  

  
 

  
 

  
I looked at the Property section of the Assembly 
  Specification.  It looks like what is there is OK.  Here it 
  is:

  
 

  
mustSupply 
  (optional) – whether the property value must be supplied 
  by the component that uses the implementation – when mustSupply="true" the 
  component must supply a value since the implementation has no default value 
  for the property.  A default-property-value should only be supplied when 
  mustSupply="false" (the default setting for the mustSupply attribute), since 
  the implication of a default value is that it is used only when a value is not 
  supplied by the using component.

  
 

  
It says that a default value should be only be 
  supplied when mustSupply is false, but it _doesn’t_ say that a default value MUST 
  be supplied.

  
 

  
Perhaps we could add the following to the SCA BPEL 
  spec at line 357 (in the paragraph that describes the meaning of 
  sca:property=”yes”):

  
 

  
“If the variable has an initialization expression (a 
  from-spec) then that becomes 
  the default value for the variable in cases where the SCA component does not 
  provide a value for that property.  If a value is provided for the property, the 
  expression is not evaluated.  If the from-spec is a literal value, where 
  it has the following form:

  
 

  
   
  <from><literal>literal 
  value</literal></from>

  
 

  
then the literal value will be represented as the 
  default value in the component type for the process.  Any other kind of 
  initialization expression will not be represented in the component 
  type.”

  
 

  
Michael

  
 

  
 

  
-----Original Message-----
From: Alex Yiu 
  [mailto:] 
Sent: Tuesday, October 16, 2007 2:30 
  PM
To: Mark Ford
Cc: ; 
  
Subject: [sca-bpel] Issue 11 - BPEL variable 
  initialization and SCA properties

  
 

  
 

  
Issue entered.

  
http://www.osoa.org/jira/browse/BPEL-11

  
 

  
Regards,

  
Alex Yiu

  
 

  
Mark Ford wrote:

  
> TARGET: SCA Client and Implementation Model 
  Specification for WS-BPEL

  
> 

  
> TITLE: BPEL variable initialization and SCA 
  properties

  
> 

  
> DESCRIPTION: Is the target variable allowed to 
  have an initialization

  
> defined within the BPEL process and if so, is 
  this initialization ignored?

  
> It seems like the initialization should be 
  allowed but not executed in the

  
> case where a process is packaged as an SCA and 
  the property is provided by

  
> the component. It's probably also worth pointing 
  out that the variable must

  
> be an element or type variable. Message variables 
  cannot be initialized by

  
> an SCA property.

  
> 

  
> 

  
>