Drools cannot resolve a global variable

Question

i'm trying to add String items to a global variable $items. But i get an error "$items cannot be resolved"

Below is snippet of my drl rule. What am i missing?

code snippet

Answer 1

you can try this

First : in drl file

global java.util.HashSet items

rule "rule 1"
    when
    then
        items.add("Item 1");
        System.err.println(items);
end

Second : in java file

KieSession kieSession = ...
kieSession.setGlobal("items",new HashSet<>());