[jboss-jira] [JBoss JIRA] (DROOLS-435) ClassCastException using nested accumulates

ClassCastException using nested accumulates ------------------------------------------- Key: DROOLS-435 URL: https://issues.jboss.org/browse/DROOLS-435 Project: Drools Issue Type: Bug Affects Versions: 5.6.0.Final, 6.0.1.Final Reporter: Mario Fusco Assignee: Mario Fusco Priority: Critical Supposing I have a data model as the following {code} public static class Driver { private final String name; private List<Car> cars = new ArrayList<Car>(); public Driver(String name) { this.name = name; } public String getName() { return name; } public void addCar(Car car) { cars.add(car); } public List<Car> getCars() { return cars; } } public static class Car { private final int speed; public Car(int speed) { this.speed = speed; } public int getSpeed() { return speed; } } {code} where each Driver can own multiple cars. I would like to calculate the average of the speed of all the Cars as I did with the following nested accumulates {code} @Test public void testNestedAccumulate() { String str = "import java.util.*;\n" + "import " + Driver.class.getCanonicalName() + ";\n" + "import " + Car.class.getCanonicalName() + ";\n" + "rule R when\n" + "accumulate ( Car( s: speed ) from accumulate ( Driver( c: cars ), " + " init(List list = new ArrayList();)," + " action(list.addAll(c);)," + " reverse(list.removeAll(c);)," + " result(list) ),\n" + " avg: average(s) )\n" + "then\n" + " System.out.println( avg );\n" + "end\n"; KnowledgeBase kbase = loadKnowledgeBaseFromString(str); StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); Driver mario = new Driver("mario"); mario.addCar(new Car(100)); mario.addCar(new Car(200)); Driver mark = new Driver("mark"); mark.addCar(new Car(300)); mark.addCar(new Car(400)); ksession.insert(mario); ksession.insert(mark); ksession.fireAllRules(); } {code} Note that splitting the nested accumulate in 2 separated accumulates as it follows fixes the problem. {code} @Test public void testAccumulates() { String str = "import java.util.*;\n" + "import " + Driver.class.getCanonicalName() + ";\n" + "import " + Car.class.getCanonicalName() + ";\n" + "rule R when\n" + "$cars : List() from accumulate ( Driver( c: cars ), " + " init(List list = new ArrayList();)," + " action(list.addAll(c);)," + " reverse(list.removeAll(c);)," + " result(list) )\n" + "accumulate ( Car( $s: speed ) from $cars,\n" + " $avg: average($s) )\n" + "then\n" + " System.out.println( $cars );\n" + " System.out.println( $avg );\n" + "end\n"; KnowledgeBase kbase = loadKnowledgeBaseFromString(str); StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); Driver mario = new Driver("mario"); mario.addCar(new Car(100)); mario.addCar(new Car(200)); Driver mark = new Driver("mark"); mark.addCar(new Car(300)); mark.addCar(new Car(400)); ksession.insert(mario); ksession.insert(mark); ksession.fireAllRules(); } {code}