factory, query

[John Fuller <jfuller@wernervas.com>]

In ASAP an observer requests that a factory create service instances.
Currently we just use URIs for addressing.

The factory knows how to create the instance, what it's been told to 
create and when it created it.
The instances themselves can be queried for their properties.
(In the future, it would be nice to make these WSRF properties).

So, the factory can list the instance ids it's created, but it can't 
necessarily be expected
to know about the current state of the instances and end users are 
likely to want to say
"give me the instances that are waiting to run or running".

My thought is that in the future, when the factory creates an instance
the instance could be registered in a service group for instances 
created by that factory,
then the service group could be addressed as an endpoint for a query to
get instance properties which would return a list of instance properties
from service instances in the group satisfying an optional xpath query 
filter for instance selection.

Thoughts?