[jboss-jira] [JBoss JIRA] Commented: (JBRULES-515) java NullPointerException when using constraints between fields in same object

java NullPointerException when using constraints between fields in same object ------------------------------------------------------------------------------ Key: JBRULES-515 URL: http://jira.jboss.com/jira/browse/JBRULES-515 Project: JBoss Rules Issue Type: Bug Security Level: Public(Everyone can see) Affects Versions: 3.0.4 Environment: Linux Reporter: Sridhar Chandrasekharan Assigned To: Mark Proctor Consider the following files:- 1) Foo.java package com.foo; public class Foo { private int a; private int b; public Foo(int a, int b) { super(); this.a = a; this.b = b; } public boolean test() { return (a > b); } public int getA() { return a; } public int getB() { return b; } } ****************************************************************************** 2) FooTest.java package com.foo; import java.io.InputStreamReader; import java.io.*; import org.drools.RuleBase; import org.drools.RuleBaseFactory; import org.drools.WorkingMemory; import org.drools.compiler.PackageBuilder; import org.drools.rule.Package; public class FooTest { /** * This is a sample file to launch a rule package from a rule source file. */ public static final void main(String[] args) { try { //load up the rulebase RuleBase ruleBase = readRule(); WorkingMemory workingMemory = ruleBase.newWorkingMemory(); //go ! workingMemory.fireAllRules(); } catch (Throwable t) { t.printStackTrace(); } } /** * Please note that this is the "low level" rule assembly API. */ private static RuleBase readRule() throws Exception { //read in the source Reader source = new InputStreamReader( FooTest.class.getResourceAsStream( "/Foo.drl" ) ); //optionally read in the DSL (if you are using it). //Reader dsl = new InputStreamReader( DroolsTest.class.getResourceAsStream( "/mylang.dsl" ) ); //Use package builder to build up a rule package. //An alternative lower level class called "DrlParser" can also be used... PackageBuilder builder = new PackageBuilder(); //this wil parse and compile in one step //NOTE: There are 2 methods here, the one argument one is for normal DRL. builder.addPackageFromDrl( source ); //Use the following instead of above if you are using a DSL: //builder.addPackageFromDrl( source, dsl ); //get the compiled package (which is serializable) Package pkg = builder.getPackage(); //add the package to a rulebase (deploy the rule package). RuleBase ruleBase = RuleBaseFactory.newRuleBase(); ruleBase.addPackage( pkg ); return ruleBase; } } *************************************************** 3) Foo.drl package com.foo rule "Initialization rule" when #conditions then assert(new Foo(1,1)); assert(new Foo(2,1)); assert(new Foo(2,3)); assert(new Foo(3,2)); assert(new Foo(3,4)); assert(new Foo(4,3)); end rule "a greater than b" when f : Foo(x : a, b < x) then System.out.println("a=" + f.getA() + " b=" + f.getB() ); end ****************************************** I get the following error when running the program java.lang.NullPointerException at org.drools.rule.BoundVariableConstraint.isAllowed(Unknown Source) at org.drools.common.BetaNodeBinder.isAllowed(Unknown Source) at org.drools.reteoo.LeftInputAdapterNode.assertObject(Unknown Source) at org.drools.reteoo.ObjectSource.propagateAssertObject(Unknown Source) at org.drools.reteoo.ObjectTypeNode.assertObject(Unknown Source) at org.drools.reteoo.Rete.assertObject(Unknown Source) at org.drools.reteoo.ReteooRuleBase.assertObject(Unknown Source) at org.drools.reteoo.ReteooWorkingMemory.doAssertObject(Unknown Source) at org.drools.common.AbstractWorkingMemory.assertObject(Unknown Source) at org.drools.base.DefaultKnowledgeHelper.assertObject(Unknown Source) at org.drools.base.DefaultKnowledgeHelper.assertObject(Unknown Source) at com.foo.Rule_Initialization_rule_0.consequence(Rule_Initialization_rule_0.java:7) at com.foo.Rule_Initialization_rule_0ConsequenceInvoker.evaluate(Rule_Initialization_rule_0ConsequenceInvoker.java:18) at org.drools.common.DefaultAgenda.fireActivation(Unknown Source) at org.drools.common.DefaultAgenda.fireNextItem(Unknown Source) at org.drools.common.AbstractWorkingMemory.fireAllRules(Unknown Source) at org.drools.common.AbstractWorkingMemory.fireAllRules(Unknown Source) at com.foo.FooTest.main(FooTest.java:27) org.drools.spi.ConsequenceException: java.lang.NullPointerException at org.drools.common.DefaultAgenda.fireActivation(Unknown Source) at org.drools.common.DefaultAgenda.fireNextItem(Unknown Source) at org.drools.common.AbstractWorkingMemory.fireAllRules(Unknown Source) at org.drools.common.AbstractWorkingMemory.fireAllRules(Unknown Source) at com.foo.FooTest.main(FooTest.java:27) Caused by: java.lang.NullPointerException at org.drools.rule.BoundVariableConstraint.isAllowed(Unknown Source) at org.drools.common.BetaNodeBinder.isAllowed(Unknown Source) at org.drools.reteoo.LeftInputAdapterNode.assertObject(Unknown Source) at org.drools.reteoo.ObjectSource.propagateAssertObject(Unknown Source) at org.drools.reteoo.ObjectTypeNode.assertObject(Unknown Source) at org.drools.reteoo.Rete.assertObject(Unknown Source) at org.drools.reteoo.ReteooRuleBase.assertObject(Unknown Source) at org.drools.reteoo.ReteooWorkingMemory.doAssertObject(Unknown Source) at org.drools.common.AbstractWorkingMemory.assertObject(Unknown Source) at org.drools.base.DefaultKnowledgeHelper.assertObject(Unknown Source) at org.drools.base.DefaultKnowledgeHelper.assertObject(Unknown Source) at com.foo.Rule_Initialization_rule_0.consequence(Rule_Initialization_rule_0.java:7) at com.foo.Rule_Initialization_rule_0ConsequenceInvoker.evaluate(Rule_Initialization_rule_0ConsequenceInvoker.java:18) ... 5 more If I change the 2nd rule to rule "a greater than b" when f : Foo() and eval(f.test()) then System.out.println("a=" + f.getA() + " b=" + f.getB() ); end It works as expected.