Re: PatternConflict exception

[Konstantin Beznosov <beznosov@baptisthealth.net>]

Bob and others,

As far as I understand the semantics of add/delete/set_evalautors() and
get_policy_decision_evaluators() from last submitters meeting (I've not checked
if it is reflected in the current submission text), if a resource name matches
more than one pattern then  get_policy_decision_evaluators() is supposed to
return a union of evaluators that are registered with all patterns which the
resource name matches. And, it is NOT an implementation-dependent thing. Please
Bob Blakley, John and Carol correct me if I misunderstood this.
If my understanding is correct, then add/set_evaluators() can NOT rise
PatternConflict exception.

Let's make a decision on it today or tomorrow.


> It is my impression that the patterns can either be edited for consistency
> at registration time or the EvaluatorLocator can make a decision on which
> of two conflicting patterns to use, or even to use both.  From the spec the
> above seems to be an implementation decsision.  I personally would think
> that an implentation could have better performance if it did the conflict
> check at registration time, but that would be an implemenation decision.
> 
> So what is a conflict, well if I have the following two patterns:
> 
> A*
> AB*
> 
> Then a resource name "ABigPile" could be matched by either pattern. An
> implemenationa might choose to not make this a conflict and have AB* take
> precedence or it could consider it to be a conflict.
> 
> Bottom line, it appears to be an implementation decision and it should have
> a way of indicating the fact that it considers something to be a conflict.
> 
> 
> Bob
> 
> 
> At 10:36 AM 2/25/99 -0500, you wrote:
> >Carol or Bob,
> >
> >Quick question on semantics of exception PatternConflict. The current
> >description of the exception is as follows:
> >
> >"The PatternConflict exception is thrown by the
> >PolicyEvaluatorLocatorAdmin when an register_resource_name_pattern()
> >detects a pattern that conflicts 
> with
> >an existing registered pattern."
> >
> >What kind of conflict do you have in mind, which could happen that will
> >cause this exception to be raised?
> >
> >Thanks
> >Konstantin
> >


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