[rules-users] Temporal rules in decision table

[Wolfgang Laun]

As you have Level with a field date, you can access that point in time in
milliseconds, using getTimeInMillis(). For the current time, you might
insert an object of class Current with a member now of class Calendar.

rule closest
when
    Current( $now: now )
    $level: Level( $value == 2, $date: date )
    not $x: Level( Math.abs( $x.getDate().getTimeInMillis() -
$now.getTimeInMillis() ) < Math.abs( $date.getTimeInMillis() -
$now.getTimeInMillis() ) )
then
    // $level is the Level fact closest to Current with a level of 2
end

Untested. If the long expression gives you trouble, try enclosing it in
eval(...).
-W


On 11 March 2014 18:14, JChrist <io.christod at gmail.com> wrote:

> Hello everyone,
> I was messing with drools v6.0.1.Final the past week and I have not been
> able to completely understand how to integrate the rule engine to my
> specification.
>
> For the needs of my project, I want to regularly insert some data in the
> engine, similar to the following:
> class Level { double value;Calendar date; }
> this class contains some values at specific time points (both in the past
> and in the future).
>
> I would like to be able create a decision table based on the "current" time
> (plus or minus a variable offset) and the value of the closest Level to
> that
> time point.
>
> For example, assuming it is '2014-11-03 19:10:00' and the level objects in
> the session currently are:
> '1.0 2014-11-03 18:00:00' and '2.0 2014-11-03 19:00:00',
>
> I would want a rule to say that if current level value is 2.0 then do some
> stuff and it would make a match.
>
> I would really appreciate any help on how to overcome this issue, as well
> as
> any good examples/tutorials regarding this.
>
> Kind regards.
>
>
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/Temporal-rules-in-decision-table-tp4028638.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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