Сравните даты в слюнях

Мой файл правил, как показано ниже,

import com.springapp.mvc.model.Person; 
dialect "java"
rule "4" 
    when
        $person:Person(((date > "20-Jan-2015") && (date < "20-Dec-2015")) && (call_count >= "299"))
    then
        System.out.println("Beep");
end

Я добавил следующий объект человека и правила огня, как показано ниже,

Person person = new Person();
person.date = "20-Feb-2015";
person.call_count = 400;
kSession.insert(person);
int fires = kSession.fireAllRules();

Но он не напечатал "Beep". Я думаю, что условия не совпадают, но я не могу понять, почему это происходит. Как я могу сравнить даты в слюнях?

Мой фактический набор правил,

package Customer_Loyalty_Categorization;
import com.springapp.mvc.model.Person; 
dialect "java"

rule "4" 
    when
        $person:Person(((date > "10-Nov-2015") && (date < "10-Dec-2015")) && (call_count >= "299"))
        $person:Person(((date > "10-Nov-2015")&&(date < "30-Dec-2015")) && (call_count >= "299"))
    then
        System.out.println("Point rule runs.");
        $person.points = ($person.call_count)*0.2;
end

rule "6" 
    when
        $person:Person(call_count >= "599")
    then
        System.out.println("Category rule runs.");
        $person.setCategory('PLATINUM');
end

И после изменения типа переменной даты человека я получил следующее исключение,

java.lang.RuntimeException: Unable to Analyse Expression date > "20-Nov-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date > "20-Nov-2015" ....}]
                    ^
[Line: 8, Column: 8] : [Rule name='4']

Unable to Analyse Expression date < "20-Dec-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date < "20-Dec-2015" ....}]
                    ^
[Line: 8, Column: 8] : [Rule name='4']

Unable to Analyse Expression date > "01-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date > "01-Jan-2015" ....}]
                    ^
[Line: 40, Column: 8] : [Rule name='1']

Unable to Analyse Expression date < "07-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date < "07-Jan-2015" ....}]
                    ^
[Line: 40, Column: 8] : [Rule name='1']

Unable to Analyse Expression date > "01-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date > "01-Jan-2015" ....}]
                    ^
[Line: 48, Column: 8] : [Rule name='2']

Unable to Analyse Expression date < "07-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date < "07-Jan-2015" ....}]
                    ^
[Line: 48, Column: 8] : [Rule name='2']

Unable to Analyse Expression date > "05-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date > "05-Jan-2015" ....}]
                    ^
[Line: 48, Column: 8] : [Rule name='2']

Unable to Analyse Expression date < "10-Jan-2015":
[Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String]
[Near : {... date < "10-Jan-2015" ....}]
                    ^
[Line: 48, Column: 8] : [Rule name='2']

Я создаю правила в виде набора строк и преобразовываю их в базу знаний, используя следующую функцию:

public void createKnowledgeBase(){
        String ruleSet = loadRuleSet();//generate rules as strings.
        try {
            System.out.println(ruleSet);
            long start = System.currentTimeMillis();
            if(ruleSet!=null){
                KnowledgeBuilder knowledgeBuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
                Resource myResource = ResourceFactory.newReaderResource(new StringReader(ruleSet));
                knowledgeBuilder.add(myResource, ResourceType.DRL);
                if (knowledgeBuilder.hasErrors()) {
                    throw new RuntimeException(knowledgeBuilder.getErrors().toString());
                }
                knowledgeBase = KnowledgeBaseFactory.newKnowledgeBase();
                knowledgeBase.addKnowledgePackages(knowledgeBuilder.getKnowledgePackages());
            }
            long finish = System.currentTimeMillis();
            System.out.println("Execution time = " + (finish-start) + " milliseconds.");
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }