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.
>
>
>
