Handling an orderOrder placed → In stock?; In stock? → Order from supplier (no); Order from supplier → In stock? (delivered); In stock? → Take payment (yes); Take payment → Orders database; Orders database → ShippedOrder placed → In stock?In stock? → Order from supplier (no)Order from supplier → In stock? (delivered)In stock? → Take payment (yes)Take payment → Orders databaseOrders database → ShippednodeliveredyesOrder placedIn stock?Order from supplierTake paymentOrders databaseShipped