For several days I'm trying to run Drools in Netbeans but it just doesn't work like I want it to. I even tried to get it working as a maven project but that didn't work as well. I describe what I do to create the project, hopefully someone can give me a hint.
First of i need it to work without maven because I'm restricted to not use it. But before I put it in the real project I want to test it.
So first I create a new project
Create lib folder in project and putting following jars in it:
With this Setup I create classes (both in package: Drools) DroolsMain (test without webserver and gui for faster debugging)
public class DroolsMain {
private static KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
private static Collection<KnowledgePackage> pkgs;
private static KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
private static StatefulKnowledgeSession ksession;
public static void main(final String[] args) {
init();
initMessageObject();
fireRules();
}
private static void init() {
String myRule = "import Drools.Message rule \"Hello World 2\" when message:Message (type==\"Test\") then System.out.println(\"Test, Drools!\"); end";
Resource myResource = ResourceFactory.newReaderResource((Reader) new StringReader(myRule));
kbuilder.add(myResource, ResourceType.DRL);
if(kbuilder.hasErrors()) {
System.out.println(kbuilder.getErrors().toString());
throw new RuntimeException("unable to compile dlr");
}
pkgs = kbuilder.getKnowledgePackages();
kbase.addKnowledgePackages(pkgs);
ksession = kbase.newStatefulKnowledgeSession();
}
private static void fireRules() {
ksession.fireAllRules();
}
private static void initMessageObject() {
Message msg = new Message();
msg.setType("Test");
ksession.insert(msg);
}
}
and the above used Message class
public class Message {
private String type;
private String message;
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
I now can run that code and have a the message returned.
Now i wanted to try it with Kie...
i just comment the methods in DroolsMain main() method. and put a Kie method in like current Drools documentation p. 172-174 there:
private static void kieTest() {
KieServices kieServices = KieServices.Factory.get();
KieContainer kContainer = kieServices.getKieClasspathContainer();
StatelessKieSession kSession = kContainer.newStatelessKieSession();
Applicant bob = new Applicant("Mr. Bob", 16);
//assertTrue(bob.isValid());
kSession.execute(bob);
//assertFalse(bob.isValid());
}
I didn't put the Applicant.class in here becaus its just a bean with 3 attributes. Also I create DRL applicant.drl file:
package Drools "Is of valid age"
import Drools.Applicant
when
$a : Applicant(age < 18)
then
$a.setValid(false);
end;
So this obviously does not work because Kie has maven dependencies so i tried this: 1. Add directories: - DroolsTest/resources/ - DroolsTest/resources/META-INF - DroolsTest/resources/META-INF/maven - DroolsTest/resources/Drools 2. Create DroolsTest/resources/META-INFkmodule.xml
Content:
<?xml version="1.0" encoding="UTF-8"?>
<kmodule xmlns="http://www.drools.org/xsd/kmodule">
<kbase name="Drools" packages="Drools">
<ksession name="ksession-drools" />
</kbase>
</kmodule>
Create DroolsTest/resources/META-INF/maven/pom.properties Content: (groupId my package name), (artifactId my project name)
groupId=Drools artifactId=DroolsTest version=1
Compiling this throws a RuntimeException:
Exception in thread "main" java.lang.RuntimeException: Cannot find a default KieSession
at org.drools.compiler.kie.builder.impl.KieContainerImpl.findKieSessionModel(KieContainerImpl.java:555)
at org.drools.compiler.kie.builder.impl.KieContainerImpl.newKieSession(KieContainerImpl.java:548)
at org.drools.compiler.kie.builder.impl.KieContainerImpl.newKieSession(KieContainerImpl.java:531)
at Drools.DroolsMain.kieTest(DroolsMain.java:43)
at Drools.DroolsMain.main(DroolsMain.java:52)
C:\Users\...\AppData\Local\NetBeans\Cache\8.1\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 3 seconds)
Is there a solution to get Kiew working without maven or can I read in a file without it?
UPDATE:
I tried launes solution:
import java.io.File;
import org.kie.api.KieBase;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.Results;
import org.kie.api.io.Resource;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
public class DroolsMain {
private void ntry() {
KieServices kieServices = KieServices.Factory.get();
KieFileSystem kfs = kieServices.newKieFileSystem();
File rule = new File("src/main/resources/Drools/applicant.drl");
Resource res = kieServices.getResources().newFileSystemResource(rule);
kfs.write(res);
KieBuilder kieBuilder = kieServices.newKieBuilder(kfs).buildAll();
Results results = kieBuilder.getResults();
System.out.println("---Messages---");
System.out.println(results.getMessages());
KieContainer kieContainer = kieServices.newKieContainer(kieServices.getRepository().getDefaultReleaseId());
KieBase kieBase = kieContainer.getKieBase();
KieSession kieSession = kieBase.newKieSession();
}
public static void main(final String[] args) {
DroolsMain dm = new DroolsMain();
dm.ntry();
}
}
I also added all jars from the drools distribution. Now it compiles and has no errors
That's how I do it, no maven, no XML:
public void build() throws Exception {
KieServices kieServices = KieServices.Factory.get();
KieFileSystem kfs = kieServices.newKieFileSystem();
//...
Resource res = ...;
kfs.write( "src/main/resources/simple.drl", res );
KieBuilder kieBuilder = kieServices.newKieBuilder( kfs ).buildAll();
Results results = kieBuilder.getResults();
if( results.hasMessages( Message.Level.ERROR ) ){
System.out.println( results.getMessages() );
throw new IllegalStateException( "### errors ###" );
}
KieContainer kieContainer =
kieServices.newKieContainer( kieServices.getRepository().getDefaultReleaseId() );
KieBase kieBase = kieContainer.getKieBase();
kieSession = kieBase.newKieSession();
}
I usually use a Resource such as
kieServices.getResources().newInputStreamResource( fis )
since reading from a file is more flexible.