Yes, your rule entered in an infinite loop because when every time you insert/modify/retract a Fact, rules are reevaluated to check if the insertion/modification/retraction generates activations or not. In your case, your rule is being reevaluated every time you update your $a object, the evaluation ends firing the rule, and this starts an endless loop.
If you only have this behavior with this rule, you can consider using the "no-loop" attribute. If your problem is multiple rules being re executed (and you don't wont that) you can use "lock-on-active" attribute. Try to read the documentation about these attributes for further information.
It is very important for the people new in drools to understand the life cycle of a rule.
Best,
On Thu, Jun 3, 2010 at 7:33 PM, Fnu Mahalakshmi
<FMahalakshmi@nyx.com> wrote:
Hi,
I tried what you said but program goes into an infinite loop.
It does not break out of the when loop only.
I did exactly as you mentioned.
In the test information I put in a.type = "Prod"
And a.bObject(new B());
Any idea whats wrong??
Thanks,
M
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Today's Topics:
1. Re: Object Referencing error: (Esteban Aliverti)
----------------------------------------------------------------------
Message: 1
Date: Thu, 3 Jun 2010 17:51:10 -0300
From: Esteban Aliverti <esteban.aliverti@gmail.com>
Subject: Re: [rules-users] Object Referencing error:
To: Rules Users List <rules-users@lists.jboss.org>
Message-ID:
<AANLkTimeZIJ5VfMTBESLFJIWoc_4MEZSXbKMIXAvJRiC@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
You can't modify bobject, becuase it doesn't exist inside the session. You
just created it a few lines above. Maybe you need an insert() or maybe you
need the bobject reference from the LHS. Something like this:
*rule* "prod"
*when*
$a :A(Type == "Prod" , objectB != "")
*then*
B bobject = *new* B();
$a.getObjectB().setType( "Prod" );
$a.getObjectB().setId($a.getNumber().getId());
*update*($a);
* end*
Note that you need to update $a and not B, because A is the inserted Fact in
your session.
Best,
2010/6/3 Fnu Mahalakshmi <FMahalakshmi@nyx.com>
> Hi,
>
>
>
> I am getting the following error when I try to do complex object
> referencing in drools:
>
> My class:
>
> A{
>
> String Type;
>
> B objectb;
>
> //getters and setters for above
>
> }
>
>
>
> My rules:
>
>
>
> *rule* "prod"
>
>
>
> *when*
>
> $a :A(Type == "Prod" , objectB != "")
>
> *then*
>
> B bobject = *new* B();
>
> bobject.setType( "Prod" );
>
> bobject.setId($a.getNumber().getId());
>
> *update*(bobject);
>
>
>
> *end*
>
> * *
>
> *I want to basically output a file which has updated values of B (type,
> Id)
>
> *
>
> * *
>
> *Error:*
>
> *org.drools.spi.ConsequenceException*: *org.drools.FactException*: Update
> error: handle not found for object: com.org.Ip@f42ad0. Is it in the
> working memory?
>
> at
> org.drools.base.DefaultConsequenceExceptionHandler.handleException(*
> DefaultConsequenceExceptionHandler.java:13*)
>
> at org.drools.common.DefaultAgenda.fireActivation(*
> DefaultAgenda.java:558*)
>
> at org.drools.common.DefaultAgenda.fireNextItem(*
> DefaultAgenda.java:518*)
>
> at org.drools.common.AbstractWorkingMemory.fireAllRules(*
> AbstractWorkingMemory.java:475*)
>
> at org.drools.common.AbstractWorkingMemory.fireAllRules(*
> AbstractWorkingMemory.java:439*)
>
> at com.org.DroolsTest.main(*DroolsTest.java:30*)
>
> Caused by: *org.drools.FactException*: Update error: handle not found for
> object: com.org.Ip@f42ad0. Is it in the working memory?
>
> at org.drools.base.DefaultKnowledgeHelper.update(*
> DefaultKnowledgeHelper.java:100*)
>
> at com.org.Rule_Prod_Ip_0.consequence(*Rule_Prod_Ip_0.java:10*)
>
> at com.org.Rule_Prod_Ip_0ConsequenceInvoker.evaluate(*
> Rule_Prod_Ip_0ConsequenceInvoker.java:22*)
>
> at org.drools.common.DefaultAgenda.fireActivation(*
> DefaultAgenda.java:554*)
>
> ... 4 more
>
>
>
> Please help! I am very new to drools! Not able to figure out why this
> error:
>
>
>
> I am using eclipse and working on Windows machine. Error above was
> generated on eclipse console.
>
>
>
> Thank you.
>
>
>
> M
>
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