Hello.java

package org.sonarsource.tests.simple;

import java.util.Collection;

import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;

public class Hello {

  public static void run() throws Exception {
    new Hello().execute(new String[] { "hello.drl" }, new Object[0]);
  }

  public void execute(String[] rules, Object[] facts) throws Exception {

    KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
    KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();

    for (int i = 0; i < rules.length; i++) {
      String ruleFile = rules[i];
      System.out.println("Loading file: " + ruleFile);
      kbuilder.add(ResourceFactory.newClassPathResource(ruleFile, Hello.class), ResourceType.DRL);
    }

    Collection<KnowledgePackage> pkgs = kbuilder.getKnowledgePackages();
    kbase.addKnowledgePackages(pkgs);
    StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();

    for (int i = 0; i < facts.length; i++) {
      Object fact = facts[i];
      System.out.println("Inserting fact: " + fact);
      ksession.insert(fact);
    }

    ksession.fireAllRules();
  }
}