Adobe observations on parameterized query mechanism

Regrepers,

I'm sorry that this feedback could not have been submitted
pre-publication, but here it is anyway.  I've asked one of my key
developers to perform an in depth analysis of the differences between
v2.5 and v3.0, and their implementation consequences to aid in my
planning activities.  The following section, I felt, is appropriate for
distribution to the technical committee.

We feel that this "pruning" feature deserves some attention, and will
likely vary our compliance to the specification in this instance in
order to provide a more understandable behaviour to our API clients.  

Best Regards,

Matt

Parameterized Query Support (NEW):

AdhocQueries stored in the registry may include parameters. Parameters
start with ‘$’ and may include the following characters [a-z] [A-Z]
[0-9]. Parameters may not start with a numeric value. Once parameters
have been added to the stored query it can then be invoked through an
AdhocQueryRequest containing an AdhocQuery with the id of the stored
AdhocQuery. The AdhocQuery element contains slots with values for each
non-context parameter of the adhoc query. Context parameters are
provided by the registry.

Current context parameters include:

- $currentUser: Id attribute of the current registry user.

- $currentTime: current system time.

Deviating from the Specification:

- The specification instructs Registry implementations to “prune”
predicates of parameters which were not included in the
AdhocQueryRequest. Instead the registry should return an
UnsupportedOperationException when receiving a request to invoke a
stored procedure without the correct number of parameters. An
implementation of this “pruning” mechanism would be ambiguous and error
prone. It is very difficult to determine exactly which sections of a
filter query should be pruned. It could also make developing
applications against the registry more difficult to debug. If a
developer forgets to add a parameter value the registry will silently
trim the query and return results.

Extending Parameterized Query Support:

- Parameterized query supported could be extended to allow a client to
submit default values for the parameters along with the parameterized
query. This would allow similar behavior to the pruning defined in the
spec but would require more explicit instructions from the client.