[rules-users] Another question on how to use map

[Brody bach]

Hi Edson,

thanks a lot for the advice. In the mean time I tried to create another
class which encapsulate the data, so that I don't have any list and map
anymore.
But as you already kindly give the syntax... I tried that syntax before and
somehow it didn't work too.
Unfortunately I can't give the exception I got because I already changes the
codes a lot.

Thanks
bb


Edson Tirelli-3 wrote:
> 
>     Hi
> 
>     As a general advice, try to avoid using abstract data structures
> (lists,
> maps, etc) as facts, since they have no semantics in the problem domain.
> If
> you have students, insert each student in the working memory. If you have
> student activities, either have an activities list "as a student
> attribute",
> or create a domain object that relates students to their activity list.
> 
>     If you do the above, rules will be so much simpler and more
> performant,
> that you will not regret.
> 
>     But, since you asked, I see no reason for you to not insert students
> directly, instead of the list of students. Your rule would be like:
> 
> when
>     $std : Student( $id : id )
>     $map : Map(  )
>     $act : Activity ($date : date, length >  180) from $map[$id]
> then
> end
> 
>     []s
>     Edson
> 
> 2009/6/24 Brody bach <brodybach at yahoo.com>
> 
>>
>> Hi,
>>
>> I need to put a map into the working memory and make some check on the
>> values
>>
>> I have an object called Student with Id
>> And for every student there is a list of activity.
>> Each activity has date and the time for the activity
>> What I will be putting in the working memory looks as follows:
>>
>> List<Student> studentList = getStudentList();
>> Map<Student, List<Activity>> studentActivityMap =
>> getStudentActivities(studentList);
>> List objects = new ArrayList();
>> objects.add(studentList);
>> objects.add(studentActivityMap);
>>
>> ksession.execute(objects);
>>
>> ====================
>>
>> Now i need to check for every student, if there is/are activity(ies) 
>> which
>> needs more than 2 hours. If yes, give an output information which
>> mention,
>> which student and on which day the activity is longer than 2 hours
>>
>> when
>> $studentList : List
>> $std : Student($id : id) from $studentList
>> $activityList : ****how to get the list of activity for the student with
>> this $id from the given map *****
>> $act : Activity ($date : date, length >  180) from $activityList
>>
>> then
>> (print something out using $id from std and $date from act)
>>
>>
>> Would really appreciate any help and hints here
>>
>> Regards
>> bb
>> --
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>>
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>>
> 
> 
> 
> -- 
>  Edson Tirelli
>  JBoss Drools Core Development
>  JBoss by Red Hat @ www.jboss.com
> 
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> 
> 

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