[rules-users] lock-on-active clarification needed

[Esteban Aliverti]

Thanks for your clarifications and thoughts.
My misunderstanding was because I always thought that lock-on-active meant
lock-on-RULE-active. Something like lock after the first activation and do
not unlock until the agenda group is changed.
The real meaning is lock-on-AGENDA_GROUP-active. Meaning: do not create
activations of this rule (no matter if using update(), modify(), insert()
or retract()) if the agenda group where it belongs is active.

Best Regards!


XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Esteban Aliverti
- Blog @ http://ilesteban.wordpress.com


On Thu, Nov 15, 2012 at 7:54 AM, Mattias Nilsson Grip <
mattias.nilsson.grip at redpill-linpro.com> wrote:

> 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 at statestreet.com>
> To: "Rules Users List" <rules-users at 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 at lists.jboss.org [mailto:
> rules-users-bounces at 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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