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

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(a)uk.sopragroup.com&gt; 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-t... > Sent from the Drools: User forum mailing list archive at Nabble.com. > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users