[rules-users] Working with collections

[Marcin Krol]

Hello everyone,

I'm a beginner in Drools, so please account for that. :-)

How do I use memberOf operator when working with collections? Depending 
on a day of week, I want to check if a day is a working day or weekend day.

I tried this:

package com.sample
dialect "mvel"
import com.sample.ThermostatTimeData;
import com.sample.Thermostat.WorkDay;
import com.sample.Thermostat.WorkDays;


rule "Rule 1"
	
when
	$wd : WorkDays()
	$ttd : ThermostatTimeData( day memberOf $wd.daylist )
	//$ttd: ThermostatTimeData ( day == "Monday" || day == "Tuesday" || day 
== "Wednesday" || day == "Thursday" || day == "Friday" )

then
	insert( new WorkDay() );
	System.out.println("inserting new workday");
end


with this in my Thermostat class:

public static class WorkDays {
  private String[] dl = {"Monday", "Tuesday", "Wednesday", "Thursday", 
"Friday"};
	
  public WorkDays() {
  }
	
  public String[] getDaylist() {
	return this.dl;
  }
}


Now the above rule works fine when I select days using the regular fact 
field selection in Drools:

$ttd: ThermostatTimeData ( day == "Monday" || day == "Tuesday" || day == 
"Wednesday" || day == "Thursday" || day == "Friday"

However, when I try to access WorkDays.dl or WorkDays.daylist(), the 
rule doesn't fire (the program output is empty).

Regards,
MK