thanks a lot

2008/7/29, Ingomar Otter <iotter@mac.com>:
There is a mechanism called truth maintenance ensuring for example

A -> B
B -> C

that C becomes false when it's premise (B) becomes false as well.
What it basically does it track the LHS side of the rule and undoes asserted facts when there are no more "facts" to support it (activate the rules in question).
Look at the documentation for logicals / truth mainteance. It's pretty cool.

For your case:

rule "light2on"
when
       LIght(name=="0/0/2", actualvalue=="1")
then
     insertLogical( new LightIsOn(2))
end

the fact "LightIsOn" will only be true (in the working memory) as long as the LHS of the rule above is still true. For example if acutalvalue becomes 0, that fact would vanish automagically.
That implies that you use facts to make statements about your system (not using behind the scene callbacks) - but from my very little experience I would say this is a good practice anyway. Fiddeling with activations make me suspicious ;-) - But then it all depends on your particular problem at hand.

--I


rule "light 2 on"
dialect "java"
when
Light (name=="0/0/2", actualvalue=="1");
then
System.out.println("luce 2 on");
end


Am 29.07.2008 um 14:42 schrieb Claudio Rainoldi:


i'm sorry i'm a new drools user.. Can you try to be a little more clear?
thanks..


2008/7/29, Ingomar Otter <iotter@mac.com>:

Use logicals.

Am 29.07.2008 um 11:20 schrieb Claudio Rainoldi:

Hi everyone,
isn'it there a way to find when a rule isn't more active.
For example if i have this rule:


rule "light 2 on"
dialect "java"
when
Light (name=="0/0/2", actualvalue=="1");
then
System.out.println("luce 2 on");
end


when someone turn on the light 2 i discover that the rule is fired using
an
Agenda Event Listener and the method afterActivationFired;
But when someone turn off the ligth isn't there a similar way to discover
that the rule "light 2 on" isn't more active.
My only solution is to use the dual rule:

rule "light 2 on_dual"
dialect "java"
when
not (Light (name=="0/0/2", actualvalue=="1"));
then
System.out.println("luce 2 off");
end

Isn't there a more sample way to do this?
Thanks in advance.


Cla
_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users


_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users

_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users

_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users