[rules-users] how to count distinct nested property?

[Jeremy Ary]

My last comparison there may be problematic as well...too focused on the
accumulate to see the obvious. I think that approach might still require an
eval to check the size constraint on the list and we don't really want
that.

What you could do instead, however, is insert the hashset into the working
memory in that rule's consequence and have a 2nd rule that's just HashSet (
size > 1 ) and its consequence does your actions and retracts the hashset
back out of memory.

- J


On Tue, Jul 22, 2014 at 9:39 AM, Jeremy Ary <jeremy.ary at gmail.com> wrote:

> err, typo there, add() and remove() should be using $myId instead of $id
>
>
> On Tue, Jul 22, 2014 at 9:38 AM, Jeremy Ary <jeremy.ary at gmail.com> wrote:
>
>> I wonder if something like this might do it?
>>
>> when
>>     $set : HashSet ( ) from  accumulate ( ObjectA ( $myId : objectC.myId ),
>>                               init ( HashSet uniqueIds = new HashSet<String>(); ),
>>                               action ( uniqueIds.add($id); ),
>>                               reverse ( uniqueIds.remove($id); ),
>>                               result ( uniqueIds ) )
>>     HashSet ( this == $set, size > 1 )
>> then
>>     // consequence
>> end
>>
>>
>> - Jeremy
>>
>>
>>
>> On Tue, Jul 22, 2014 at 8:42 AM, richardhands <
>> richard.hands at uk.sopragroup.com> wrote:
>>
>>> Hi,
>>>
>>> I’m trying to wrap my head around how to use a combination of accumulate
>>> from and collect from to get a count of how many unique items there are
>>> of a
>>> nested child property and run the RHS of a rule if it’s > 1
>>>
>>> So I have
>>>
>>> Many of Object A
>>>
>>> Each one contains
>>> An object B
>>> An object C
>>>
>>> Object C contains a nested child property
>>>
>>> So
>>>
>>> A
>>> +-+-B
>>>    |
>>>    +-C – property myId
>>>
>>> (many of these in the working memory)
>>>
>>> The rule I’m working with right now is
>>>
>>> rule "B must only be at 1 myId per day"
>>>     when
>>>       $b : B()
>>>       $c : C()
>>>       $aList : ArrayList (size > 1)
>>>         from collect(
>>>               A(b == $b, c.getDate() == $c.getDate()) )
>>>       eval ( RulesUtils.countIdsForC ($aList) > 1 )
>>>    then
>>>      //fire some rules here
>>> end
>>>
>>> and the RulesUtils method is
>>>
>>>   public static int countIdsForC (List  aList)
>>>   {
>>>     Set<Integer> myIds = new HashSet<Integer>();
>>>     for (A a : aList)
>>>     {
>>>       myIds.add(a.getC().getMyId());
>>>     }
>>>     return myIds.size();
>>>   }
>>>
>>>
>>> Now I’m well aware that this is sub-optimal, and indeed is firing lots of
>>> extra times and is really (Really) slow.  I can vizualise that this
>>> should
>>> easily be possible with some combination of compound accumulate and
>>> collect
>>> statements, but for the life of me I can’t work out the correct
>>> arrangement
>>> (This is actually for use in an optaplanner ruleset so it will
>>> potentially
>>> be working on lots of data, over many iterations).
>>>
>>> Any suggestions on how to do this the way I know it needs to be,
>>> greatfully
>>> appreciated 
>>>
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>> http://drools.46999.n3.nabble.com/how-to-count-distinct-nested-property-tp4030424.html
>>> Sent from the Drools: User forum mailing list archive at Nabble.com.
>>>
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>>
>
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