Hi all,
It is 2 days I am fighting with a strange behaviour of insertLogical in rules
having from pattern in conditions : it works the first time, and not after ...
-----------------------------------------
Here is my use-case (simplified) :
I have a class that represent a Flight. A Flight has a start/end datetime and
is associated with a Airplane and a list of Crew :
class Flight {
String airplaneId;
List<String> crewIds;
Date start;
Date end;
}
I want to maintain an alert list that contains all overlaps for each airplane
and each crew. So I have rules like:
rule "Overlap Airplane"
when
$f1 : Flight($airplaneId : airplaneId)
$f2 : Flight(this != $1, airplaneId == $airplaneId, ... and periods
intersecting ... )
then
insertLogical(new Alert(...));
end
rule "Overlap Crews"
when
$f1 : Flight()
$crew : String from $f1.getCrewIds()
$f2 : Flight(this != $1, eval($f2.getCrewIds().contains($crew)) , ... and
periods intersecting ... )
then
insertLogical(new Alert(...));
end
-----------------------------------------
Ok. So what I do to test all that stuff :
- create a new session
- add a first single Flight --> no alerts at all, normal
- add a second Flight insersecting the first one with same airplane and same
crews list --> 3 new alerts inserted (one for airplane, one for each crew) :
normal
- remove this second Flight --> the 3 preivous alerts are retracted : still ok
- re-add this second Flight --> only the 'airplane' rule triggers, I only get
one new alert insteads of the previous same 3 .... The alerts not inserted
correspond to the rule having 'from' in it
-----------------------------------------
To test that it is the source of the problem, I add a new explicit association
object that I insert in WM :
class CrewAffectation {
String idCrew;
String idFlight;
}
For each inserted Flight, I also insert corresponding new CrewAffectation
objects. (in case of retract, I retract them of course).
I change the last rule to something like :
rule "Overlap Crews"
when
$f1 : Flight($id1 : id
$f2 : Flight(this != $1, $id2 : id, ... and periods intersecting ... )
$crewAff1 : CrewAffectation($idCrew : idCrew, idFlight== $id1)
$crewAff2 : CrewAffectation(idCrew == $idCrew, idFlight== $id2)
then
insertLogical(new Alert(...));
end
And with this 'no-from' approach, everything is working as expected.
-----------------------------------------
In addition, I suspect the truth maintenance system to have leaks, and notably
in the source kBase.
Why ? Because I was facing problems by reusing the same kBase to generate
multiples kSessions : The first session created reacted well, while all the
folowing not.
And it was in fact the same problem as the one described here : usage of from
and insertLogical in the same rule.
The first created session adds and retract my 3 alerts, the second created
session only adds the airplane alert.
With using the explicit association object, I can reuse my kBase and everything
is working well.
-----------------------------------------
Does someone already faced the problem ?
Does it looks like a real bug to dev team or am I doing something wrong (but as
it work once, I guess it is a bug) ?
Vincent
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