[bpel4people] NEW ISSUE: (Re-)Evaluation and instantiation of logicalpeople groups

[Matthias Kloppmann <matthias-kloppmann@de.ibm.com>]

TARGET: BPEL4People Working Draft 02

DESCRIPTION: When are logical people
groups re-evaluated, in particular for parameterized logical people groups.

Resolution of logical people groups
happens on several occasions: When referenced from an htd:from clause,
or when referenced from a getLogicalPeopleGroup XPath function. When accessed
the first time through either means, a logical people group is evaluated.
In a BPEL4People process, the same logical people group may be referenced
again, possibly with a different set of arguments values. The specification
needs to state what the rules are for re-evaluating (re-resolving) the
logical people group.

PROPOSAL: Instances of an LPG are per
set of values for the parameters. Consequently, when arguments of parameters
are changed between referencing an LPG the first time and the second time,
it MUST be re-evaluated/re-resolved. When parameters are not changed between
referencing an LPG the first time and the second time, it MAY be re-evaluated/re-resolved.
(Motivation: Allow a modeler to reuse
a logical people group, e.g., in a loop, with different bindings -- the
example we discussed was regionalSalesPeople("Wales"), regionalSalesPeople("Sussex")
-- you want to be sure the second one does not retrieve the former result,
unless they are really the same. Allow in implementation for caching: When
regionalSalesPeople("Wales") is called several times, the result
could be cached, because re-resolution is not mandated.)

Regards,
Matthias

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