There were a couple of ways mentioned in the Drools documentation for 4.0.7.

 

1)      Eval is the Quick  way to get this done. This does have a performance penalty though

2)      Read up on using the -> operator that allowed you to go deeper into the object hierarchy.

3)      A third way which I used was to write setter and getter methods for fields I needed in the rules condition in the root class itself. Since Drools introspects on setters and getters this seemed to work.

 

To take an example, if I have a class as follows:-

 

Class B{

int a;

public int geta() {};

public int seta() {};

}

 

Class A {

 

B b;

 

public int getA()

{

Return this.b.geta();

}

 

Public void seta(int b)

{

this.b.seta(b);

}

 

 

}

 

 

 

 

 

Hi,

I am planning to use Drools - JBoss Rules Engine. My requirement is to disburse mails from my application to different groups based on various criteria. I want to use Drools here.

My object structure is as follows:

class A{

String B = "";

B b;

C c;
}

Hence Obj A has embedded objects within it, and obj B and C further has embedded objects.

class B {

String X;

Z z;

}

class Z{

String t;

String s;

}

The decision on sending the mails based on the fields in embedded objects of A. I pass instance of A to Drools

Format of drl file:

package...;

import ..;

rule "Test"

when $a:A(B(Z(s == "testvalue")))

then

$a.setSomething();

update($a);

end

I wanted to know if this (accessing fields in embedded/child object) is feasible with Drools.

I get an error saying "UNable to compile myfile.drl when i try to fo this.

Could some one look into this issue and let me know the reason for this ?

 

Thanks

-D