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Comments on the 3 Dec 04 CDL specification

From: Tony Fletcher <tony_fletcher@btopenworld.com>
Date: Tue, 7 Dec 2004 17:34:08 -0000
To: <public-ws-chor@w3.org>
Message-ID: <003c01c4dc82$f5a00260$590a0a0a@corp.choreology.com>
Dear Colleagues,
Some comments on the 3 Dec 04 CDL specification:
1)  Rationale: Short circuit evaluation of Boolean conditions should be
explicitly allowed.
Add to section 2.4.3 Expressions (or elsewhere if a better place can be
Boolean conditional expressions MUST use short circuit evaluation techniques
whatever the setting of the block attribute.  That is once the value of a
conditional expression can be evaluated and the result will no longer change
if further variables become available or time based functions become true,
the conditional expression returns its value.
Note:  If it is thought this incorrect and we should not permit short
circuit evaluation for some good reason then we should specifically prohibit
it and add text similar to that above but stating MUST NOT instead.
2)   Rationale:  Cover the complete condition as well for time functions.
In section WS-CDL supplied functions the text for 

xsd:boolean hasDurationPassed and xsd:boolean hasDeadlinePassed

mentions the guard and repeat conditions explicitly, but does not mention
the complete condition.  One could interpret this as meaning that these two
functions can not be used in a complete condition, which I am sure is not
Add to section for hasDurationPassed:
Returns "true" if used in a complete condition of a Choreography when the
duration specified by elapsedTime at the caller for the Role specified by
roleName has elapsed.


Add to section for hasDeadlinePassed:
Returns "true" if used in a complete condition of a Choreography when the
time specified by deadlineTime at the Role specified by roleName has


Section 2.4.8 Choreography Lifeline

Add at the end:

If no finalizers were defined in a choreography, then when the choreography
enters the Successfully Completed state, it is also Closed.



In section 2.4.8 and elsewhere the words 'enables' and 'enabled' are used in
the sense of 'run', 'perform', etc.  That is active completion of the
element or whatever is being referred to.  My understanding of enables /
enabled is 'ready to run / perform (but do not actually run / perform until
something else happens).

Am I alone in this or do others find this use of language confusing /
inaccurate?  (And if so should we try to find another word - trouble is
'perform' might imply use of the perform element and run is perhaps to real
system oriented.  What about 'carry out' / 'carried out', etc as


Section 2.4.10 Choreography Finalization


.        A single Finalizer Block to semantically "rollback" the
Choreography, typically called "compensation"


.        A single Finalizer Block to semantically "rollback" the


Section 9 References

UDDI has now moved into OASIS - change to reference the OASIS specifications
change to:

[8] OASIS Committee Draft "Universal Description, Discovery and Integration"
version 3.0.2



In the schema why has a namespace prefix been defined for XML Schema and xs:
added to the schema tag, but not to any of the other tags from the XML
Schema language (such as 'element', 'extension', and so on)?


Section WS-CDL supplied functions uses the prefix xsd:  We should be
consistent and either use no prefix, xs: or xsd: consistently in the text
and schema.

Best Regards     Tony
A M Fletcher
Cohesions  (TM)
Business transaction management software for application coordination
<http://www.choreology.com/> www.choreology.com
Choreology Ltd., 68 Lombard Street, London EC3V 9LJ     UK
Tel: +44 (0) 1473 729537   Mobile: +44 (0) 7801 948219
 <mailto:tony.fletcher@choreology.com> tony.fletcher@choreology.com
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Received on Tuesday, 7 December 2004 17:34:42 UTC

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