public TransEntruckBill makeBill(Message message, Iterator<String> orderList) { for (int i = 0; i < message.length(); i++) { if (message.getInform(i).equals("")) { return null; } } TransEntruckBill bill = new TransEntruckBill(message, orderList); double fee = calculator.calculateFee(bill); bill.setPayment(fee); dataServer.addBill(bill); approver.addBill(bill.submit()); return bill; }