Seems that there is a confusion here ... window:length(X) is constraining the events timestamps to be in a time-windows of length X (in seconds). To contrain the number of accumulated facts, it must be done by adding a constraint in the resulting list : $list : ArrayList(size > Nb) from accumulate(Class1($a:a) over window:length(X) from entry-point "Point" ... @wolfgang : if you use an internal counter in the accumulate, how can you test it internaly ? return empty (or null) list if max not reached ? $list : ArrayList() from accumulate($obj : Class1($a:a) over window:length(X) from entry-point "Point" init ( ArrayList list = new ArrayList(); ), action ( list.add($obj); ), return ( if (list.size() < Nb {return null;} else {return list;} )) ----- Mail original ----- De: "Wolfgang Laun" <wolfgang.laun(a)gmail.com&gt; À: "Rules Users List" <rules-users(a)lists.jboss.org&gt; Envoyé: Mercredi 16 Mai 2012 13:02:46 Objet: Re: [rules-users] Evaluation of the of rules with 'window:length' event windows Accumulate the count of elements (in addition to whatever you accumulate) and test the result as being == X. As of (IIRC) 5.3.0, you can write multi-function accumulates. -W On 16/05/2012, senyatur <senya.touretski(a)emc.com&gt; wrote: _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

oups ... Should have checked before ... sorry. So window:length(X) take only a max of X previous events (so including from 0 to X, which the problem here) strange construction ... "$count: count(1)" is part of the pattern ? then automatically incremented in $count variable ? Does the accumulate still return a List or something else ?

ok, got it. not a strange construction, but a beautiful one !! thx ----- Mail original ----- If you want to have a list, you can have it in addition to count: accumulate( $w: Whatever(...) from window:length( 10 ), $count: count(1), $list: collectList( $w ),... ) although that would be redundant. But if you'd just need the (for instance) sum, it would be useful. accumulate( Whatever( $x:x, ... ) from window:length( 10 ), $count: count(1), $sum: sum( $x ) ) Note that this is a *complete* CE, beginning with "accumulate". -W _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users