[rules-users] Request for assistance in removing eval from a rule

Tue Sep 16 18:48:09 EDT 2008

Edson -
Thank you very much for the reply.  I have one more question.  In the
example below I changed RulesUtil to be a global name 'ruleUtil' (since
its member variables do not change), and reran the rule (with the
'ruleUtil:RulesUtil()' line omitted).

When I do this, and execute the rule below, I get a null pointer
exception on PredicateConstraint.  The first and last parts of the stack
trace are:
org.drools.RuntimeDroolsException: Exception executing predicate
com.bah.aims.rules.Rule_my_rule_0ReturnValue0Invoker at 36289b82
 at
org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:2
16)
 at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:132)
 at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(Compo
siteObjectSinkAdapter.java:318)
 at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:140)
 at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(Compo
siteObjectSinkAdapter.java:299)
 at
org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153)
...
Caused by: java.lang.NullPointerException
 at
com.bah.aims.rules.Rule_my_rule__0.returnValue0(Rule_my_rule_0.java:27)
 at
com.bah.aims.rules.Rule_my_rule_0ReturnValue0Invoker.evaluate(Rule_myRul
e_0ReturnValue0Invoker.java:21)
 at
org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:2
10)
 ... 29 more

I'm not sure what is causing this.  Any thoughts?
If it helps, RulesUtil.containsKeywordString()  checks to see if a
string passed in is present in a list of keywords held in the class.

Thanks - 
David

________________________________

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Edson Tirelli
Sent: Tuesday, September 16, 2008 9:56 AM
To: Rules Users List
Subject: Re: [rules-users] Request for assistance in removing eval from
a rule

   David,

   Eval is really bad for perf, but still, sometimes it is the only way
to do things like call methods. So, in your case, it all depends on what
"containsKeywordString()" method is doing?

   Also, is RulesUtil just a utility class? I mean with no data you
reason over? if so, I strongly advise you to make it a global, instead
of matching it in the rule like a fact.

   Regarding evals, inline evals are just a bit lighter than top level
evals, but there is an important difference:

* inline evals MUST be time consistent, i.e., they must evaluate to the
same value everytime they are called.
* top level evals can deal with changes appropriately 

    []s
    Edson

2008/9/15 Warren, David [USA] <warren_david at bah.com>

	Folks - 

	After seeing the thread on evals hurting performance a couple of
weeks ago, I tried to remove them from a rule set we are using (running
Drools 4.0.4), and have had limited success.

	An example is shown below.  We're using evals every time we make
a call to "rulesUtil", a helper class we have for checking strings for
keywords.  Two questions:

	1. Does using inline evals (like below) hurt performance as much
as using non-inline evals?
	2. If so, any thoughts for how to rewrite this rule to avoid
using the eval?

	rule
	'my rule'
	salience 790
	activation-group "priorityRule"
	when
	ruleUtil : RulesUtil( )
	s1 : Sensor( source == "X, $rfp : RFP , eval(
ruleUtil.containsKeywordString($rfp, "Y" )) , $tcn : TCN)
	s2 : Sensor( TCN != $tcn, source == "Z"
	then
	System.out.println("my rule");
	priority.setPriorityName("A");

	end

	Thanks,
	David Warren

________________________________

	From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Edson Tirelli
	Sent: Friday, September 05, 2008 2:59 PM
	To: Rules Users List
	Subject: Re: [rules-users] Drools, Performance issues on 4.0.7
Vs 2.5

	   Start by eliminating the evals and writing your constraints
properly inside the patterns. Drools 3+ is orders of magnitude faster
than Drools 2.x, but you need to leverage its power in your rules.
Please read the manual as the version 3 was a completely rewrite of
version 2. Version 4 is an improvement over 3.

	   As an example, look at this:
http://blog.athico.com/2006/11/rush-hour-and-content-based-routing.html

	   []s
	   Edson

	2008/9/5 Rout, Sushanta (ThoughtMill) <Sushanta.Rout at ihg.com>

		We were using Drools 2.5 version earlier. Now we have
switched to drools
		4.0.7. But we see significant issues with performance
like drools 4.0.7
		is three times slower than 2.5 . Has anybody encountered
the issue?

		Here is a sample of the rule, we have some more similar
to this.
		rule "test"
		       dialect "java"
		       activation-group "group1"
		       when
		               $croNumberDetailsRequest :
CRONumberDetailsRequest()
		               $resdirectPhoneNumber :
ResdirectPhoneNumber()

eval($resdirectPhoneNumber.getType().getId() == 5 &&

$resdirectPhoneNumber.isValidForBrand($croNumberDetailsRequest.getBrand(
		)) &&

$croNumberDetailsRequest.getRegion() != null &&

$resdirectPhoneNumber.isValidRegion($croNumberDetailsRequest.getRegion()
		) &&

$croNumberDetailsRequest.getLocale() != null &&

$resdirectPhoneNumber.isValidForLocaleId($croNumberDetailsRequest.getLoc
		ale()) &&

$resdirectPhoneNumber.isValidSlot($croNumberDetailsRequest.getSlot()));

		       then
		               ResultList.add($resdirectPhoneNumber);
		end

		_______________________________________________
		rules-users mailing list
		rules-users at lists.jboss.org
		https://lists.jboss.org/mailman/listinfo/rules-users

	-- 
	Edson Tirelli
	JBoss Drools Core Development
	JBoss, a division of Red Hat @ www.jboss.com

	_______________________________________________
	rules-users mailing list
	rules-users at lists.jboss.org
	https://lists.jboss.org/mailman/listinfo/rules-users

-- 
Edson Tirelli
JBoss Drools Core Development
JBoss, a division of Red Hat @ www.jboss.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20080916/b9d1f7ea/attachment.html 