Here is an example from the eclipse basic test project, i have added a new Rule allways to be fired with 
lock-on-active true and also added a function to make a printiln in the console to see what gets evaluated.

Code to run:

package com.sample;

import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.logger.KnowledgeRuntimeLogger;
import org.drools.logger.KnowledgeRuntimeLoggerFactory;
import org.drools.runtime.StatefulKnowledgeSession;

/**
 * This is a sample class to launch a rule.
 */
public class DroolsTest {

	public static final void main(String[] args) {
		try {
			// load up the knowledge base
			KnowledgeBase kbase = readKnowledgeBase();
			StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
			KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger(ksession, "test");
			// go !
			Message message = new Message();
			message.setMessage("Hello World");
			message.setStatus(Message.HELLO);
			ksession.insert(message);
			ksession.fireAllRules();
			logger.close();
		} catch (Throwable t) {
			t.printStackTrace();
		}
	}

	private static KnowledgeBase readKnowledgeBase() throws Exception {
		KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
		kbuilder.add(ResourceFactory.newClassPathResource("Sample.drl"), ResourceType.DRL);
		KnowledgeBuilderErrors errors = kbuilder.getErrors();
		if (errors.size() > 0) {
			for (KnowledgeBuilderError error: errors) {
				System.err.println(error);
			}
			throw new IllegalArgumentException("Could not parse knowledge.");
		}
		KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
		kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
		return kbase;
	}

	public static class Message {
		
		public static final int HELLO = 0;
		public static final int GOODBYE = 1;

		private String message;

		private int status;

		public String getMessage() {
			return this.message;
		}

		public void setMessage(String message) {
			this.message = message;
		}

		public int getStatus() {
			return this.status;
		}

		public void setStatus(int status) {
			this.status = status;
		}
		
	}

}


Rules file:

package com.sample
 
import com.sample.DroolsTest.Message;
 
function boolean testEval(String arg) {
	System.out.println(arg);
	return true;
}
 
 
rule "Hello World"
	when
		eval(testEval("Hello World eval up"))
		m : Message( status == Message.HELLO, myMessage : message )
		eval(testEval("Hello World eval down "))
	then
		System.out.println( myMessage ); 
		m.setMessage( "Goodbye cruel world" );
		m.setStatus( Message.GOODBYE );
		update( m );
end

rule "Allways"
	lock-on-active true
	when
		eval(testEval("Allways eval up"))
		Message()
		eval(testEval("Allways eval down"))
	then
		System.out.println("Allways has run");
end

rule "GoodBye"
	when
		eval(testEval("GoodBye eval up"))
		Message( status == Message.GOODBYE, myMessage : message )
		eval(testEval("GoodBye eval down"))
	then
		System.out.println( myMessage );
end


Out put:

Hello World eval up
Hello World eval down 
<b>Allways eval up
Allways eval down</b>
GoodBye eval up
<b>Allways has run</b>
Hello World
GoodBye eval down
<b>Allways eval down</b>
Goodbye cruel world

Why the rules Allways has been evaluated again after been fired, for what i understand if the rule has lock-on-active true It shouldnt be evaluated again since it shouldnt run any more.



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View this message in context: <a href="http://drools-java-rules-engine.46999.n3.nabble.com/lock-on-active-why-keeps-evaluating-tp973374p973447.html">Re: lock-on-active, why keeps evaluating?</a><br>
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