[rules-users] Working with collections

[Michael Neale]

The days list property needs to be a Collection (at the moment I think
it uses the collection semantics in java, which sadly arrays are not
part of the collections family).

You can do Arrays.asList() to convert it to a list in the getter
method, and it should work. If you however make it a hashset, it in
theory will be slightly faster then most other collection types.

On Sat, Sep 27, 2008 at 2:04 AM, Marcin Krol <mrkafk at gmail.com> wrote:
> 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
>
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-- 
Michael D Neale
home: www.michaelneale.net
blog: michaelneale.blogspot.com