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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The simplist solution is just to change your condition to be $a : Applicant(age < 18, valid != false)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thomas<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Esteban Aliverti<br>
<b>Sent:</b> 20 January 2012 14:20<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> Re: [rules-users] Infinit loop in simple example<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">import spikes.Applicant<br>
rule "Is of valid age" when<br>
$a : Applicant( age < 18 )<br>
then<br>
modify( $a ) { valid = false };<br>
end<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#222222">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.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#222222">Read the documentation manual about some attributes you can use in your rules to avoid this behavior: no-loop, lock-on-active.</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Arial","sans-serif";color:#222222">Best Regards,<br clear="all">
</span><br>
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX<br>
<br>
Esteban Aliverti<br>
- Developer @ <a href="http://www.plugtree.com" target="_blank">http://www.plugtree.com
</a><br>
- Blog @ <a href="http://ilesteban.wordpress.com" target="_blank">http://ilesteban.wordpress.com</a><br>
<br>
<o:p></o:p></p>
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<p class="MsoNormal">On Fri, Jan 20, 2012 at 3:12 PM, roland.kofler <<a href="mailto:roland.kofler@gmail.com">roland.kofler@gmail.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">Simple example loops ad infinitum if executed:<br>
<br>
package spikes;<br>
<br>
import org.springframework.roo.addon.javabean.RooJavaBean;<br>
<br>
@RooJavaBean<br>
public class Applicant {<br>
private final String string;<br>
private final int age;<br>
public boolean valid=true;<br>
<br>
public Applicant(String string, int i) {<br>
this.string = string;<br>
this.age = i;<br>
}<br>
}<br>
DroolsSpikeTest<br>
<br>
package spikes;<br>
<br>
import static org.junit.Assert.*;<br>
<br>
import org.drools.KnowledgeBase;<br>
import org.drools.runtime.StatelessKnowledgeSession;<br>
import org.junit.Test;<br>
import org.junit.runner.RunWith;<br>
import org.springframework.beans.factory.annotation.Autowired;<br>
import org.springframework.test.context.ContextConfiguration;<br>
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;<br>
<br>
@RunWith(SpringJUnit4ClassRunner.class)<br>
@ContextConfiguration(locations={"classpath:**/applicationContext-drools.xml"})<br>
public class DroolsSpikeTest {<br>
<br>
@Autowired<br>
private KnowledgeBase kbase;<br>
<br>
@Test<br>
public void testspikeDroolRule() {<br>
StatelessKnowledgeSession ksession =<br>
kbase.newStatelessKnowledgeSession();<br>
Applicant a = new Applicant("Mr John Smith", 16);<br>
assertTrue(a.isValid());<br>
ksession.execute(a);<br>
assertFalse(a.isValid());<br>
}<br>
<br>
}<br>
applicationContext-drools.xml<br>
<br>
<?xml version="1.0" encoding="UTF-8" standalone="no"?><br>
<br>
<beans xmlns="<a href="http://www.springframework.org/schema/beans" target="_blank">http://www.springframework.org/schema/beans</a>"<br>
xmlns:aop="<a href="http://www.springframework.org/schema/aop" target="_blank">http://www.springframework.org/schema/aop</a>"<br>
xmlns:context="<a href="http://www.springframework.org/schema/context" target="_blank">http://www.springframework.org/schema/context</a>"<br>
xmlns:jee="<a href="http://www.springframework.org/schema/jee" target="_blank">http://www.springframework.org/schema/jee</a>"<br>
xmlns:tx="<a href="http://www.springframework.org/schema/tx" target="_blank">http://www.springframework.org/schema/tx</a>"<br>
xmlns:xsi="<a href="http://www.w3.org/2001/XMLSchema-instance" target="_blank">http://www.w3.org/2001/XMLSchema-instance</a>"<br>
xmlns:drools="<a href="http://drools.org/schema/drools-spring" target="_blank">http://drools.org/schema/drools-spring</a>"<br>
xsi:schemaLocation="<a href="http://www.springframework.org/schema/aop" target="_blank">http://www.springframework.org/schema/aop</a><br>
<a href="http://www.springframework.org/schema/aop/spring-aop-3.1.xsd" target="_blank">http://www.springframework.org/schema/aop/spring-aop-3.1.xsd</a><br>
<a href="http://www.springframework.org/schema/beans" target="_blank">http://www.springframework.org/schema/beans</a><br>
<a href="http://www.springframework.org/schema/beans/spring-beans-3.1.xsd" target="_blank">http://www.springframework.org/schema/beans/spring-beans-3.1.xsd</a><br>
<a href="http://www.springframework.org/schema/context" target="_blank">http://www.springframework.org/schema/context</a><br>
<a href="http://www.springframework.org/schema/context/spring-context-3.1.xsd" target="_blank">http://www.springframework.org/schema/context/spring-context-3.1.xsd</a><br>
<a href="http://www.springframework.org/schema/jee" target="_blank">http://www.springframework.org/schema/jee</a><br>
<a href="http://www.springframework.org/schema/jee/spring-jee-3.1.xsd" target="_blank">http://www.springframework.org/schema/jee/spring-jee-3.1.xsd</a><br>
<a href="http://www.springframework.org/schema/tx" target="_blank">http://www.springframework.org/schema/tx</a><br>
<a href="http://www.springframework.org/schema/tx/spring-tx-3.1.xsd" target="_blank">http://www.springframework.org/schema/tx/spring-tx-3.1.xsd</a><br>
<a href="http://drools.org/schema/drools-spring" target="_blank">http://drools.org/schema/drools-spring</a><br>
<a href="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" target="_blank">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</a>"><br>
<br>
<drools:kbase id="kbase1"><br>
<drools:resources><br>
<drools:resource id="licenseRule" type="DRL"<br>
source="classpath:spikes/licenseApplication.drl"/><br>
</drools:resources><br>
<drools:configuration><br>
<drools:mbeans enabled="true" /><br>
</drools:configuration><br>
</drools:kbase><br>
<drools:ksession kbase="kbase1" type="stateless" id="ksessionStateless"<br>
name="stateless1" ><br>
</drools:ksession><br>
</beans><br>
<br>
licenseApplication.drl<br>
<br>
import spikes.Applicant<br>
rule "Is of valid age" when<br>
$a : Applicant( age < 18 )<br>
then<br>
modify( $a ) { valid = false };<br>
end<br>
<span style="color:#888888"><br>
<span class="hoenzb">--</span><br>
<span class="hoenzb">View this message in context: <a href="http://drools.46999.n3.nabble.com/Infinit-loop-in-simple-example-tp3675536p3675536.html" target="_blank">
http://drools.46999.n3.nabble.com/Infinit-loop-in-simple-example-tp3675536p3675536.html</a></span><br>
<span class="hoenzb">Sent from the Drools: User forum mailing list archive at Nabble.com.</span><br>
<span class="hoenzb">_______________________________________________</span><br>
<span class="hoenzb">rules-users mailing list</span><br>
<span class="hoenzb"><a href="mailto:rules-users@lists.jboss.org">rules-users@lists.jboss.org</a></span><br>
<span class="hoenzb"><a href="https://lists.jboss.org/mailman/listinfo/rules-users" target="_blank">https://lists.jboss.org/mailman/listinfo/rules-users</a></span></span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
</div>
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