[rules-users] Complex rule

[Bryan Hansen]

Thank you Edson, this helps me get going in the right direction.

In this logic:

Period( $sd : startDate, $ed : endDate )
    Number( intValue > 10 ) from accumulate(
         Day( date >= $sd && <= $ed, status == Day.WORKED ),
         count( 1 ) )

Where is date coming from? As I read the statements, I am getting startDate
and endDate from a Period object that I pass in. The Number() statement just
says to take the result and parse it as a number right? What about Day and
date though? Is Day a java object from my Java code? I searched the docs
looking for a Day object in the drools docs and didn't come up with
anything. I am assuming it is because of the Day.WORKED status, would date
just be a member of that object?

Thanks,

Bryan

On Mon, Nov 3, 2008 at 7:51 PM, Edson Tirelli <tirelli at post.com> wrote:

>
>    Bryan,
>
>    The main decision here is how to do Date arithmetic, since java does not
> provide easy to use APIs for that. So, the simplest way IMO, from a rule
> authoring perspective, is to have a "constraint object" that contain both
> boundary dates of your rule. Lets call it "Period".
>    So, if you want to write your rule saying:
>
> "Take a break if you worked more than 10 days in the given period."
>
>     Just do:
>
> rule "take a break"
> when
>     Period( $sd : startDate, $ed : endDate )
>     Number( intValue > 10 ) from accumulate(
>          Day( date >= $sd && <= $ed, status == Day.WORKED ),
>          count( 1 ) )
> then
>     // take a break
> end
>
>     If your Day object is some kind of container object, use a chained from
> to iterate over them:
>
> rule "take a break"
> when
>     Period( $sd : startDate, $ed : endDate )
>     DailyReport( $days : days )
>     Number( intValue > 10 ) from accumulate(
>          Day( date >= $sd && <= $ed, status == Day.WORKED ) from $days,
>          count( 1 ) )
> then
>     // take a break
> end
>
>    Hope it helps.
>
>      Edson
>
> 2008/11/3 Bryan Hansen <bryankhansen at gmail.com>
>
>> Not really sure how to go about writing this in a rule or whether or not
>> the logic belongs in a rule (I think it does, but if you don't please
>> comment as to why).
>>
>> I have a list of objects that contain date objects. If the list contains
>> 10 objects that date are before mine then I want them to take a break.
>>
>> The business case is similar to that of an HR system. If they have worked
>> too many days out of the last 12 then they need to take a break.
>>
>> I am guessing it would have to use the "collect" attribute, but how would
>> you do the date logic in a LHS clause?
>>
>> Thanks for any guidance on this.
>>
>> _______________________________________________
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>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>
>
> --
>  Edson Tirelli
>  JBoss Drools Core Development
>  JBoss, a division of Red Hat @ www.jboss.com
>
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>
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