Bindings do not cache actual values ----------------------------------- Key: DROOLS-651 URL: https://issues.jboss.org/browse/DROOLS-651 Project: Drools Issue Type: Enhancement Affects Versions: 6.2.0.Beta3 Environment: Win7, Drools 6.2.0 Beta3 (probably all Drools versions) Reporter: Marc Dzaebel Assignee: Mario Fusco Priority: Minor Create sample Drools project, add following method to the Message class: {noformat} public List<String> list() { System.out.println("Call!"); return Arrays.asList("one", "two"); } {noformat} sample.drl: {noformat} package com.sample import com.sample.DroolsTest.Message; import java.util.List; import java.util.ArrayList; rule "" when m : Message(L : list(), L.size>0) then System.out.println("L:"+L); end {noformat} Running the project will result in the following output: {noformat} Call! Call! L:[one, two] {noformat} So _list()_ is called *two* times (duplicate). This may be due to the replacement of "L" with _list()_ in the second constraint. This is ok for simple +getters+ as here HotSpot optimizes this away. However, long running methods will produce unnecessary overhead, especially if further constraints on "L" are added (which I verified produce additional calls to list()). So at least methods with one or more arguments should be saved in temporary variables that should be used in further constraints. A fix of this problem will certainly accelerate Drools performance on similar patterns. If this is not feasible, at least a comment should be added to the documentation.