Re: [rules-users] Infinit loop in simple example
import spikes.Applicant
rule Is of valid age when
$a : Applicant( age 18 )
then
modify( $a ) { valid = false };
end
By using modify() you are telling the engine that $a was modified in some
way. This causes the re-evaluation of your rule, and since $a.age is still
18, then the rule is activated and fired infinite times.
Read the documentation manual about some attributes you can use in your
rules to avoid this behavior: no-loop, lock-on-active.
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Fri, Jan 20, 2012 at 3:12 PM, roland.kofler roland.kof...@gmail.comwrote:
Simple example loops ad infinitum if executed:
package spikes;
import org.springframework.roo.addon.javabean.RooJavaBean;
@RooJavaBean
public class Applicant {
private final String string;
private final int age;
public boolean valid=true;
public Applicant(String string, int i) {
this.string = string;
this.age = i;
}
}
DroolsSpikeTest
package spikes;
import static org.junit.Assert.*;
import org.drools.KnowledgeBase;
import org.drools.runtime.StatelessKnowledgeSession;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={classpath:**/applicationContext-drools.xml})
public class DroolsSpikeTest {
@Autowired
private KnowledgeBase kbase;
@Test
public void testspikeDroolRule() {
StatelessKnowledgeSession ksession =
kbase.newStatelessKnowledgeSession();
Applicant a = new Applicant(Mr John Smith, 16);
assertTrue(a.isValid());
ksession.execute(a);
assertFalse(a.isValid());
}
}
applicationContext-drools.xml
?xml version=1.0 encoding=UTF-8 standalone=no?
beans xmlns=http://www.springframework.org/schema/beans;
xmlns:aop=http://www.springframework.org/schema/aop;
xmlns:context=http://www.springframework.org/schema/context;
xmlns:jee=http://www.springframework.org/schema/jee;
xmlns:tx=http://www.springframework.org/schema/tx;
xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance;
xmlns:drools=http://drools.org/schema/drools-spring;
xsi:schemaLocation=http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/jee
http://www.springframework.org/schema/jee/spring-jee-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://drools.org/schema/drools-spring
http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-container/drools-spring/src/main/resources/org/drools/container/spring/drools-spring-1.0.0.xsd
drools:kbase id=kbase1
drools:resources
drools:resource id=licenseRule type=DRL
source=classpath:spikes/licenseApplication.drl/
/drools:resources
drools:configuration
drools:mbeans enabled=true /
/drools:configuration
/drools:kbase
drools:ksession kbase=kbase1 type=stateless id=ksessionStateless
name=stateless1
/drools:ksession
/beans
licenseApplication.drl
import spikes.Applicant
rule Is of valid age when
$a : Applicant( age 18 )
then
modify( $a ) { valid = false };
end
--
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[rules-users] Infinit loop in simple example
Simple example loops ad infinitum if executed:
package spikes;
import org.springframework.roo.addon.javabean.RooJavaBean;
@RooJavaBean
public class Applicant {
private final String string;
private final int age;
public boolean valid=true;
public Applicant(String string, int i) {
this.string = string;
this.age = i;
}
}
DroolsSpikeTest
package spikes;
import static org.junit.Assert.*;
import org.drools.KnowledgeBase;
import org.drools.runtime.StatelessKnowledgeSession;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={classpath:**/applicationContext-drools.xml})
public class DroolsSpikeTest {
@Autowired
private KnowledgeBase kbase;
@Test
public void testspikeDroolRule() {
StatelessKnowledgeSession ksession =
kbase.newStatelessKnowledgeSession();
Applicant a = new Applicant(Mr John Smith, 16);
assertTrue(a.isValid());
ksession.execute(a);
assertFalse(a.isValid());
}
}
applicationContext-drools.xml
?xml version=1.0 encoding=UTF-8 standalone=no?
beans xmlns=http://www.springframework.org/schema/beans;
xmlns:aop=http://www.springframework.org/schema/aop;
xmlns:context=http://www.springframework.org/schema/context;
xmlns:jee=http://www.springframework.org/schema/jee;
xmlns:tx=http://www.springframework.org/schema/tx;
xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance;
xmlns:drools=http://drools.org/schema/drools-spring;
xsi:schemaLocation=http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/jee
http://www.springframework.org/schema/jee/spring-jee-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://drools.org/schema/drools-spring
http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-container/drools-spring/src/main/resources/org/drools/container/spring/drools-spring-1.0.0.xsd;
drools:kbase id=kbase1
drools:resources
drools:resource id=licenseRule type=DRL
source=classpath:spikes/licenseApplication.drl/
/drools:resources
drools:configuration
drools:mbeans enabled=true /
/drools:configuration
/drools:kbase
drools:ksession kbase=kbase1 type=stateless id=ksessionStateless
name=stateless1
/drools:ksession
/beans
licenseApplication.drl
import spikes.Applicant
rule Is of valid age when
$a : Applicant( age 18 )
then
modify( $a ) { valid = false };
end
--
View this message in context:
http://drools.46999.n3.nabble.com/Infinit-loop-in-simple-example-tp3675536p3675536.html
Sent from the Drools: User forum mailing list archive at Nabble.com.
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Re: [rules-users] Infinit loop in simple example
The simplist solution is just to change your condition to be $a : Applicant(age
18, valid != false)
Thomas
From: rules-users-boun...@lists.jboss.org
[mailto:rules-users-boun...@lists.jboss.org] On Behalf Of Esteban Aliverti
Sent: 20 January 2012 14:20
To: Rules Users List
Subject: Re: [rules-users] Infinit loop in simple example
import spikes.Applicant
rule Is of valid age when
$a : Applicant( age 18 )
then
modify( $a ) { valid = false };
end
By using modify() you are telling the engine that $a was modified in some way.
This causes the re-evaluation of your rule, and since $a.age is still 18,
then the rule is activated and fired infinite times.
Read the documentation manual about some attributes you can use in your rules
to avoid this behavior: no-loop, lock-on-active.
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Fri, Jan 20, 2012 at 3:12 PM, roland.kofler
roland.kof...@gmail.commailto:roland.kof...@gmail.com wrote:
Simple example loops ad infinitum if executed:
package spikes;
import org.springframework.roo.addon.javabean.RooJavaBean;
@RooJavaBean
public class Applicant {
private final String string;
private final int age;
public boolean valid=true;
public Applicant(String string, int i) {
this.string = string;
this.age = i;
}
}
DroolsSpikeTest
package spikes;
import static org.junit.Assert.*;
import org.drools.KnowledgeBase;
import org.drools.runtime.StatelessKnowledgeSession;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={classpath:**/applicationContext-drools.xml})
public class DroolsSpikeTest {
@Autowired
private KnowledgeBase kbase;
@Test
public void testspikeDroolRule() {
StatelessKnowledgeSession ksession =
kbase.newStatelessKnowledgeSession();
Applicant a = new Applicant(Mr John Smith, 16);
assertTrue(a.isValid());
ksession.execute(a);
assertFalse(a.isValid());
}
}
applicationContext-drools.xml
?xml version=1.0 encoding=UTF-8 standalone=no?
beans xmlns=http://www.springframework.org/schema/beans;
xmlns:aop=http://www.springframework.org/schema/aop;
xmlns:context=http://www.springframework.org/schema/context;
xmlns:jee=http://www.springframework.org/schema/jee;
xmlns:tx=http://www.springframework.org/schema/tx;
xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance;
xmlns:drools=http://drools.org/schema/drools-spring;
xsi:schemaLocation=http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/jee
http://www.springframework.org/schema/jee/spring-jee-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://drools.org/schema/drools-spring
http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-container/drools-spring/src/main/resources/org/drools/container/spring/drools-spring-1.0.0.xsd;
drools:kbase id=kbase1
drools:resources
drools:resource id=licenseRule type=DRL
source=classpath:spikes/licenseApplication.drl/
/drools:resources
drools:configuration
drools:mbeans enabled=true /
/drools:configuration
/drools:kbase
drools:ksession kbase=kbase1 type=stateless id=ksessionStateless
name=stateless1
/drools:ksession
/beans
licenseApplication.drl
import spikes.Applicant
rule Is of valid age when
$a : Applicant( age 18 )
then
modify( $a ) { valid = false };
end
--
View this message in context:
http://drools.46999.n3.nabble.com/Infinit-loop-in-simple-example-tp3675536p3675536.html
Sent from the Drools: User forum mailing list archive at Nabble.com.
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