[rules-users] Temporal rules in decision table

[Ioannis Christodoulou]

Thanks a lot for the prompt reply and the detailed example!
It took me some time but I managed to convert it to a working xls decision
table.

Now, I wanted to figure out how to automatically update the Current object
regularly, in order to re-calculate the rules over time.
My application is a java ee one. Would creating a @schedule on a singleton
method be a good solution, or is there another better advice for it?

Thanks again!

Ευχαριστώ πολύ,
   Ιωάννης Χριστοδούλου


On Tue, Mar 11, 2014 at 8:50 PM, Wolfgang Laun <wolfgang.laun at gmail.com>wrote:

> 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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>>
>
>
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