12:54 a.m.
Armand/Esteban,
I had a look at source code ( org.drools.common.DefaultAgenda.createActivation(...) ) and
as far as I can tell it should not matter if the rules match on the same facts or not. I
interpret the source code like this:
"While an agenda group or rule flow group is active, any rules within that group with
lock-on-active set to true are prevented from creating new activations"
I.e. the rule "Rule 1" cannot create an activation since its agenda group MAIN
is already active when its conditions are fulfilled.
Regards,
Mattias
----- Original Message -----
From: "Armand Welsh" <AWelsh(a)statestreet.com>
To: "Rules Users List" <rules-users(a)lists.jboss.org>
Sent: Wednesday, 14 November, 2012 11:04:36 PM
Subject: Re: [rules-users] lock-on-active clarification needed
Esteban,
I too have been confused by lock-on-active. Only after reading the definition many times,
have I come to the following conclusion:
Looking at the documentation, and other examples, I think I can how lock-on-active
behaves. From what I gather, it looks like when “init “ rule fires, the activations for
that rule consist of the DataSample() facts (all of them). You then modify the fact, but
at the same time, the lock-on-active blocks any further activations from occur as a result
of modifying the DataSample() fact.
Since “Rule 1” depends on DataSample, and it is in the same agenda group as init, “Rule 1”
cannot fire until the agenda group is changed, or the ruleflow-group is changed.
What is being blocked by lock-on-active is not the reactivation of the rule. What is being
blocked is the resultant activations as a result of modify the DataSample fact.
This block only holds true on the current focus (agenda-group or ruleflow-group). Think of
it as a way of temporarily removing the facts from the knowledge tree.
From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On
Behalf Of Esteban Aliverti
Sent: Wednesday, November 14, 2012 3:41 AM
To: Rules Users List
Subject: [rules-users] lock-on-active clarification needed
Hi all,
I'm dealing with a set of rules having the lock-on-active attribute and I'm not
getting the (at least what I understand as) expected results.
I've created an isolated JUnit test. I'm attaching it to this email.
Basically, I have 2 rules:
rule "init"
lock-on-active true
when
$d: DataSample()
then
System.out.println("Setting predefined value");
modify($d){
addValue(Parameter.PARAM_A, 10.0)
}
end
rule "Rule 1"
lock-on-active true
when
DataSample($v: values[Parameter.PARAM_A] < 20)
then
System.out.println("Rule 1: "+$v);
end
DataSample is a Java class containing a Map<Parameter, Double> where Parameter is an
enum.
In the test I'm creating a ksession and inserting an empty DataSample object.
I understand that as soon as the object is inserted, both rules are evaluated and the
result is going to be an activation of rule "init"; and this is what is actually
happening. So far so good.
Now, after I call fireAllRules() I expect that 'Rule 1' becomes active because of
the modification of the fact in "init". Well, this is not the case. I don't
see any activation for "Rule 1".
My understanding about lock-on-active is that a rule that WAS ACTIVATED is not going to be
re-activated until the current agenda group is switched. The odd thing here is that I
never had an activation for "Rule 1" so I don't see why it activation after
"init" is executed should be prevented.
So my question is: Is my understanding wrong? What is the expected behavior of
lock-on-active in this situation? I read the documentation but I couldn't get any
hint:
"
Whenever a ruleflow-group becomes active or an agenda-group receives the focus, any rule
within that group that has lock-on-active set to true will not be activated any more ;
irrespective of the origin of the update, the activation of a matching rule is discarded.
This is a stronger version of no-loop, because the change could now be caused not only by
the rule itself. It's ideal for calculation rules where you have a number of rules
that modify a fact and you don't want any rule re-matching and firing again. Only when
the ruleflow-group is no longer active or the agenda-group loses the focus those rules
with lock-on-active set to true become eligible again for their activations to be placed
onto the agenda."
Best Regards,
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Esteban Aliverti
- Blog @ http://ilesteban.wordpress.com
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