[rules-users] endless loop even with "no-loop"

[Esteban Aliverti]

no-loop only prevents loops generated by the same rule. In your scenario,
Rule A is triggering Rule B, which in turn is triggering Rule A, which is
triggering Rule B... and so on.

Try using lock-on-active instead:
http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html#d0e3573

<http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html#d0e3573>Best
Regards,

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

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


2011/3/23 Anderson Neves <anderson.ufal at gmail.com>

> Hi.
>
> I like to add negated attributes in the condition, or other attributes that
> better describe the object state, like below. If you write two rules to the
> same object state, you should think to join the rules into one rule.
>
> rule
>  when
>     $object:Type(attribute=="value", secondAttribute == false,
> thirdAttribute == "")
>  then
>     // do consequence
> end
>
> Regards,
> Anderson
>
>
> 2011/3/23 Gabor Szokoli <szocske at gmail.com>
>
>> This is I think something all of us came across while learning Drools...
>>
>> So I searched for "drools loop faq" in google but nothing useful came up.
>> I propose to extend the "inifinite recursion" section in the faq with
>> the best practices for avoiding this!
>>
>> My favorite way to avoid unnecessary activations is to include the
>> consequence among the conditions, negated:
>>
>> rule
>>  when
>>   $object:Type(attribute!="value")
>>  then
>>  modify ($object) { setAttribute("value")}
>> end
>>
>>
>> Gabor
>>
>> On Wed, Mar 23, 2011 at 12:30 PM, James Gu <jxgu at cnsh.delphi-tech.com>
>> wrote:
>> > Hi, I am working on rule and found that it is very easy to cause endless
>> > loop.
>> >
>> > For example:
>> > Rule 1 match status and update message.
>> > Rule 2 match type and update message.
>> > This will cause endless loop even I add "no-loop" on each rule. Is there
>> > anyway to avoid this? for example: each rule only execute one time, or
>> set a
>> > maximum execute times.
>> >
>> >
>> > rule "rule 1"
>> > no-loop
>> >        when
>> >                m : Message( status == Message.HELLO)
>> >        then
>> >                System.out.println( "rule 1" );
>> >                m.setMessage( "update 1" );
>> >                update( m );
>> >
>> > end
>> >
>> > rule "rule 2"
>> > no-loop
>> >        when
>> >                m:Message( type=="type1" )
>> >        then
>> >                System.out.println( "rule 2" );
>> >                m.setMessage( "update 2" );
>> >                update( m );
>> > end
>> >
>> > --
>> > View this message in context:
>> http://drools-java-rules-engine.46999.n3.nabble.com/endless-loop-even-with-no-loop-tp2719917p2719917.html
>> > Sent from the Drools - User mailing list archive at Nabble.com.
>> > _______________________________________________
>> > rules-users mailing list
>> > rules-users at lists.jboss.org
>> > https://lists.jboss.org/mailman/listinfo/rules-users
>> >
>>
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>
>
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