I am working on an application that tells how much insulin should be given to a patient with different glucose values. I have a decision object that contains the current value of glucose and the rules alter the decision object to include advice or explanations. Since the decision object is modified, I have to have some kind of state object so that rules do not loop; I have created a state object that has a series of boolean fields which are checked. However, this feels like I am circumventing the whole idea of an inference engine. So I have made an alternative helper class that contains inner classes that can be inserted as facts. Here is a sample rule with the first method: [code] rule "Detect mild hypoglycemia" when decision : GlucoseDecision( serumGlucoseConcentration < 80, serumGlucoseConcentration >= 60 ) decisionState : GlucoseDecisionState(currentGlucoseBelowRange == true, mildHypoglycemia == false) then decisionState.setMildHypoglycemia(true); decision.explain("The patient has mild hypoglycemia (serum glucose is " + decision.getSerumGlucoseConcentration() +" mg/dL)."); end [/code] Here is the same rule using the second approach: [code] rule "Detect mild hypoglycemia" when decision : GlucoseDecision( serumGlucoseConcentration < 80, serumGlucoseConcentration >= 60 ) currentGlucoseBelowRange() not(mildHypoglycemia()) then insert(new mildHypoglycemia()); decision.explain("The patient has mild hypoglycemia (serum glucose is " + decision.getSerumGlucoseConcentration() +" mg/dL)."); end [/code] My question is whether one or the other of these approaches is a better practice? Using facts would make my rules trace more sensible, I think, but perhaps it is much less efficient. Comments are appreciated. Thank you. - Mike -- View this message in context: http://www.nabble.com/Best-%28better%29-practices-question-tp20742140p207... Sent from the drools - user mailing list archive at Nabble.com.