Have you tried making your classes beans?

Eg adding getters and setters. (As a style guide in java you should generally avoid public fields and class names should start with a capital letter).

 

This would give you the following:

public class Message {

    private Numbers[] numbersArray;

 

   

    protected Numbers[] getNumbersArray() {

        return numbersArray;

    }

   

    protected void setNumbersArray(Numbers[] numbersArray) {

        this.numbersArray = numbersArray;

    }

}

 

public class Numbers {

    private int first;

    private int last;

   

    protected int getFirst() {

        return first;

    }

   

    protected void setFirst(int first) {

        this.first = first;

    }

   

    protected int getLast() {

        return last;

    }

   

    protected void setLast(int last) {

        this.last = last;

    }

}

 

Thomas

 

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of stefano corna
Sent: 14 December 2009 11:00
To: rules-users@lists.jboss.org
Subject: [rules-users] rule on Array of custom Object

 

hello,
im using drools 5.0 on eclipse and i have a problem. i want to use an array of object in my rule condition.
now i try to explain:
i have my java class with the array attribute
-------------------------------------------------
public static class Message {

   public numbers[] numbersArray;

}
--------------------------------------------
and the numbers class that rapresent the objects contained in numbersArray
----------------------------------------------
public static class numbers
{
   public int first;
   public int last;
}
--------------------------------------------------
my goal is make a rule that check if Message.numbersArray[0].first="value"
i use
-------------------------------------------------
rule "rule_001"

dialect "mvel"
when
        $msg : Message(numbersArray[0].first=="1")

then
                System.out.println("something....");
end
-------------------------------
and on runtime it give me this error:
---------------------------------------
org.drools.RuntimeDroolsException: Exception executing predicate numbersArray[0].first=="1"
        at org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:279)
        at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:143)
        at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:360)
        at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:344)
        at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:185)
        at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:146)
        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1046)
        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1001)
        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:788)
        at org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:216)
        at com.sample.DroolsTest.main(DroolsTest.java:47)
Caused by: [Error: unable to access property (null parent): first]
[Near : {... Unknown ....}]
             ^
[Line: 1, Column: 0]
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:861)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getBeanProperty(ReflectiveAccessorOptimizer.java:585)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:313)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:138)
        at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:133)
        at org.mvel2.ast.BinaryOperation.getReducedValueAccelerated(BinaryOperation.java:102)
        at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
        at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:107)
        at org.mvel2.MVEL.executeExpression(MVEL.java:978)
        at org.drools.base.mvel.MVELPredicateExpression.evaluate(MVELPredicateExpression.java:75)
        at org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:272)
        ... 10 more
-------------------------------------------------------
moreover if i try to print the "first" value:
.
.
.
then
                System.out.println(numbersArray[0].first);
end
appear this new error and i cant compile:
"BuildError: Unable to build expression for 'consequence': Failed to compile: 1 compilation error(s):
 - (1,12) unqualified type in strict mode for: numbersArray' System.out.println(numbersArray[0].first);
'"

someone can kindly help me?



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