24.9. Pet Store Example: Doing the Checkout Extract from PetStore.drl

rule "do checkout"
    dialect "java"
    when
    then
        doCheckout(frame, drools.getWorkingMemory());
end

The rule "do checkout" has no agenda group set and no auto-focus attribute. As such, it is deemed part of the default (MAIN) agenda group. This group gets focus by default when all the rules in agenda-groups that explicitly had focus set to them have run their course.
There is no LHS to the rule, so the RHS will always call the doCheckout() function.
When calling the doCheckout() function, the rule passes the global frame variable to give the function a handle to the Swing GUI.
The doCheckout() function shows a confirmation dialog to the user. If confirmed, the function sets the focus to the checkout agenda-group, allowing the next lot of rules to fire.

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