Re: [rules-users] Re: Is this scenario suitable for using Drools?

So, in my usual helpful manner I thought Drools would be a perfect match and put together what I thought would be a simple example:- package com.sample global com.sample.DBUtils dbutils; rule "a1" when $max : Integer() from accumulate( Integer( $v : intValue ) from dbutils.getNumbers(), max($v) ) then System.out.println($max); end public class DBUtils { public Integer[] getNumbers() { Integer[] numbers = new Integer[10]; for (int i = 0; i < numbers.length; i++) { numbers[i] = (int) (Math.random() * 100); } return numbers; } } However this led to some errors:- org.drools.RuntimeDroolsException: java.lang.ClassCastException: [Ljava.lang.Integer; incompatible with java.lang.Integer at org.drools.rule.Accumulate.accumulate(Accumulate.java:131) at org.drools.reteoo.AccumulateNode.assertTuple(AccumulateNode.java:127) at org.drools.reteoo.CompositeTupleSinkAdapter.createAndPropagateAssertTuple(CompositeTupleSinkAdapter.java:73) at org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:116) at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:22) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153) at org.drools.reteoo.Rete.assertObject(Rete.java:177) at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192) at org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction.execute(ReteooWorkingMemory.java:179) at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1292) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:891) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:858) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:659) at com.sample.DroolsTest.main(DroolsTest.java:36) Caused by: java.lang.ClassCastException: [Ljava.lang.Integer; incompatible with java.lang.Integer at org.drools.base.java.lang.Integer968047027$intValue.getIntValue(Unknown Source) at org.drools.base.ClassFieldExtractor.getIntValue(ClassFieldExtractor.java:197) at org.drools.rule.Declaration.getIntValue(Declaration.java:230) at com.sample.Rule_a1_0AccumulateExpression0Invoker.evaluate(Rule_a1_0AccumulateExpression0Invoker.java:16) at org.drools.base.accumulators.JavaAccumulatorFunctionExecutor.accumulate(JavaAccumulatorFunctionExecutor.java:74) at org.drools.rule.Accumulate.accumulate(Accumulate.java:123) ... 13 more Have I done something really stupid and is Drools a fit? Cheers, Mike ------------------------------ *From:* rules-users-bounces(a)lists.jboss.org [mailto: rules-users-bounces(a)lists.jboss.org] *On Behalf Of *Cheng Wei Lee *Sent:* 22 April 2008 17:27 *To:* rules-users(a)lists.jboss.org *Subject:* [rules-users] Re: Is this scenario suitable for using Drools? I've 2 algorithms to calculate the cost of a product. At any one time, there is only 1 algorithm in use. Initially algorithm 1 will be the default. Subsequently, the decision to use which algorithm will depend on customers feedback. The algorithms are: Algorithm 1: Cost = MAX(P1, T1, P2, T2, P3, T3, ...) Algorithm 2: Cost = MIN(P1, P2, P3, ...) + MIN(T1, T2, T3, ...) The values of P1, P2, ... are stored within a database. The number of Ps & Ts are unknown but can be determined by querying the database, Would drools be a good option to use to store the algorithms? If so, how could I be able to retrieve the values of P1, P2, etc from the database from within drools? Thanks! _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users