24.7. Pet Store Example: Show Items in the GUI from PetStore.drl

rule "Show Items"
    agenda-group "show items"
    dialect "mvel"
when
    $order : Order( )
    $p : Purchase( order == $order )
then
   textArea.append( $p.product + "\n");
end

The show items agenda-group has only one rule, called "Show Items" (note the difference in case). For each purchase on the order currently in the Working Memory (or Session), it logs details to the text area at the bottom of the GUI. The textArea variable used for this is a global variables.
The evaluate Agenda group also gains focus from the Explode Cart rule.