Drools date comparision when part of the rule

Question

I need to write following condition in when part of rule.

start_date<=end_date+3 months where start_date and end_date are fields of type Date.

Would anyone please tell me how can I do it?

Answer 1

First of all, it feels like a very weird rule. WHEN the start_date is later then or exactly three month after the end_date THEN execute a consequence.

I'm assuming start_date and end_date are fields of a class Foo, the rule will be as follows:

rule "I am checking if the start_date of Foo is more than or exactly three month after the end_date of Foo"
when
    Foo($start: start_date, $end: end_date, 
        $end_plus_3_month: DateUtils.addMonths($end, 3), 
        $start.compareTo($end_plus_3_month) <= 0)
then
    System.out.printf("The start_date %tD is more that or exactly 3 month after %tD.%n", $start, $end);
end