Rules are not to be "called". A rule become activated when facts match its condition. To analyse any data by a rule, it must be inserted into working memory. You can defined functions in Drools, but this is merely an alternative to coding and importing a static Java method. -W On 27 September 2012 18:53, thano <asimoon(a)gmail.com&gt; wrote:

Even without setFocus and agenda-group there can't be a loop, for two reasons. There is nothing here to reactivate either loop, and the Person fact is retracted. -W On 27 September 2012 21:07, thano <asimoon(a)gmail.com&gt; wrote:

If you want to do what I can only guess then you must insert the data as a fact into Working Memory. -W On 28 September 2012 16:58, thano <asimoon(a)gmail.com&gt; wrote:

I would recommend you to read the drools manual and the examples, especially the introduction... rule based programming is somewhat different from more traditional procedural (e.g. java) programming. It may let you solve your problems efficiently and elegantly, or just give you headaches.. :) Now, as for the examples: 1) the "then" in a rule is a "when premise then conclusion", as in (a type of) "logic", not a "then" as in "first this then that", as in sequential programming. SO, the premise is about collecting (joining) and matching (selecting) data against patterns. This said, the accumulate has to be in the LHS, not in the RHS. 2) I guess you're trying to compare the average temperature against ? is $max the max temperature? Or a threshold you provide from somewhere else? 3) I also guess you want to use the average temperature in the other rule... As Wolfgang pointed out, you have to insert it in the working memory (or use a global, but this may not the best of practices). Moreover, it's more useful to use the value to create an instance of a more "meaningful" class than simply inserting a Number. What if other rules insert Numbers? 4) Maybe you also want to make the number related to the person? It's an interesting exercise on joins, to see what happens if you add that "foreign key" or not 5) You may not need to use agenda groups, if your rules are implicitly made sequential by the patterns. If a rule can only matched something potentially inserted by another, there is no way for that rule to fire until the other has been fired itself. declare AverageTempRecord // pers : Person avg : double end rule "MrFlow" when $pers : person : Person( gender == 'M' ) accumulate ( SensorReading( $temp : temperature ) over window:time( 10m ), $max : max( $temp ), // this is the max temperature over the window, but this can't be your "$max"... $avg : average( $temp ) // ; // $avg > MAX // where do you get the threshold from? ) then insertLogical( /*$pers,*/ new AverageTempRecord( $avg ) ); end rule "Hello MR" when $p : Person() $a : AverageTemperatureRecord( /* pers == $p, */ $avg : avg ) then System.out.println( "Hello mr " + $p.getName() + ", your temp is " + $avg ); retract( $p ); end Best Davide -- View this message in context: http://drools.46999.n3.nabble.com/function-in-drools-tp4020021p4020046.html Sent from the Drools: User forum mailing list archive at Nabble.com.

Ok, so you may need something like this: 1) You need a bean to store the parameter. You can declare it in DRL, or use a normal java class and insert the instance from the main. The DRL version would be this: declare Parameters threshold : double end rule "Initialize" salience 9999 // fire first! when then insert( new Parameters( 10.0 ) ); // your value here end Or, you can set a global: // in java: kSession.setGlobal( "threshold", 1.0 ); // in DRL, at the beginning: global Double threshold; 2) You need rule "one" and something to hold your current average temperature: ( ps. sorry, the $pers : person : Person() was a typo! :) ) Now: do you need to relate the temperature to the person? I mean, how many Person are there in your workingmemory? I guess one, also considering that the SensorReading are not related to the person... In any case, here Person is acting as an "enabler fact" or "guard" which effectively decides if the rule is applicable or not. So: declare AverageTemperatureRecord // again, this or a java class value : double end rule "one" $pers : Person( gender == 'M' ) accumulate ( SensorReading( $temp : temperature ) over window:time( 10m ), $avg : average( $temp ); then insertLogical( new AverageTempRecord( $avg ) ); end Notice the use of "insertLogical" : your average will change over time (but see my remark about rule 2 below), so you may want to keep only the latest value, or a "history" with all of them? InsertLogical will make sure that a fact is retracted when its conditions no longer hold, and in case of an accumulate this is done when the aggregation set changes, i.e. whenever a SensorReading slides in or out of the window... The net effect is that the latest will take the place of the previous, which is different from keeping them all in memory, or keeping one an modifying it every time - all behaviours that can be obtained with slightly different rules. 3) Now you can write rule two: If you have the parameter object: rule "two" Parameters( $max : threshold ) $a : AverageTemperatureRecord( $avg : avg> $max ) then // do something end or you can use the global : rule "two with global " $a : AverageTemperatureRecord( $avg : avg> threshol ) then // do something end notice that your previous rule rule "two - previous" $p : Person( gender == 'M' ) Parameters( $max : threshold ) $a : AverageTemperatureRecord( $avg : avg> $max ) then // do something retract( $p ); end This rule - which does not need an agenda group - will be EVALUATED for every new AvgTempRecord (insertLogical will make sure that only the last remains in the WM, but this will not affect the evaluations: every ATR will be checked). [ Notice that this is not a "call", but a producer-consumer relation mediated by the working memory. Rule one generates some data and drops them into a common environment. Rule two "picks it up" and sees whether it matches its conditions or not. You WOULD probably need the agenda-groups if other sources could generate the ATRs for rule "two", but here rule "two" can only be activated after rule "one" has fired, producing the necessary fact] If at some point the > constraint is satisfied, the rule will be ACTIVATED and then FIRED. If the consequence retracts $p, as you were doing, the guard patterns will no longer satisfied and rule "one" (and two) will not be activated anymore. On 09/28/2012 11:01 AM, thano wrote:

Many thanks Davide -- View this message in context: http://drools.46999.n3.nabble.com/function-in-drools-tp4020021p4020049.html Sent from the Drools: User forum mailing list archive at Nabble.com.