[rules-users] Rules not firing when expected after retracting object in list

[Justin Beltran]

Thanks for the reply.

 

What if you have multiple A's set with 123?  Don't you need to collect them
to retract all A's that match that property?

 

My main concern is if you retract one or more of the A's, it's possible that
you should still have some A's that are NOT retracted, so rule B should
still fire right?

 

Justin

 

 

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Swindells, Thomas
Sent: Wednesday, July 21, 2010 8:39 AM
To: Rules Users List
Subject: Re: [rules-users] Rules not firing when expected after retracting
object in list

 

Why is rule 1 written the way it is? Why can't you just do:

rule "Rule 1 - Remove all A's that have property set to 123" 
  salience 1000 
when 
  $anA : A( property == "123" )
then 
      retract ($anA) 
end

 

Thomas

 

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Justin Beltran
Sent: 21 July 2010 16:28
To: rules-users at lists.jboss.org
Subject: [rules-users] Rules not firing when expected after retracting
object in list

 

Hi, 

I'm coming across some weird behavior in Drools 4.0.7, but maybe it's just
cause I don't understand I how Drools works.  Assume, there's a class "A"
that has a property called "property". 

As facts, I have the following list of A's: 
A1, property = 123 
A2, property = 345 
A3, property = 123 

I have two rules as follows: 

rule "Rule 1 - Remove all A's that have property set to 123" 
  salience 1000 
  lock-on-active true 
when 
  $listOfAs : ArrayList collect(A( property == "123" )) 
then 
  for (Object a: $listOfAs ) {   
      retract (a) 
  } 
end 

rule "Rule 2 - Do stuff with remaining A's" 
  salience 900 
  lock-on-active true 
when 
  $listOfAs : ArrayList collect(A()) 
then 
... 
end 

My understanding is "Rule 1" will remove the facts of class A that have
property to 123.  When it gets to "Rule 2", shouldn't the "listOfAs" only
have that one A that remains (i.e. the one where property is set to "345").
What I'm noticing is that "Rule 2" just doesn't execute at all even though
I'm assuming there is still one "A" object that hasn't been retracted.  If I
comment out the "retract" it executes "Rule 2" fine. 

Am I missing something about these rules work? 

Thanks. 
Justin

 

  _____  


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