[rules-users] first steps with drools.....first errors

[Nicola Benaglia]

Hi,
I am moving my first steps with Drools 4.0.7.

In my case I have an exam result to valuate.
I can pass an ExamDetailas fact containing (value, authLimit, lawLimit)
where authLimit may or may not be present.

How can I force to valuate a rule only if a property exists?

Here an example:

rule "Rule n.1"
dialect "mvel"
no-loop true
salience 10
    when
         exists ExamDetail(authLimit);
        $examDetail : ExamDetail( $value: value < authLimit);
    then
        System.out.println( "1 Exam passed!" + $value);
end

rule "Rule n.2"
dialect "mvel"
no-loop true
salience 10
    when
        not exists ExamDetail(authLimit);
        ExamDetail( $value: value < lawLimit);
    then
        System.out.println( "2 Exam passed! + $value);
end


With these 2 rules I expected to cover my 2 cases:
1) When I have authLimit  --> rule #1
2) When authLimit is absent --> rule #2

But I get this error (when I don't have authlimit):

Exception in thread "main" org.drools.rule.InvalidRulePackage: [14,21]:
unknown:14:21 Unexpected token 'authLimit'[25,6]: unknown:25:6
Unexpected token 'exists'[25,24]: unknown:25:24 Unexpected token 'authLimit'
    at org.drools.rule.Package.checkValidity(Package.java:424)
    at
org.drools.common.AbstractRuleBase.addPackage(AbstractRuleBase.java:394)
    at eu.tecnoprogetti.rules.seam.ExamCheck.main(ExamCheck.java:23)


Any suggestions?
Thank you for your time.
Nico