public void setProductDiscount(int productid, int discount, Session session) { Product product = DBProduct.getInstance().getProductByID(productid); if (product == null) { throw new DoesntExistException("no such username"); } SubscribedUser user = session.getSubscribedUser(); DBStore storeDB = DBStore.getInstance(); StoreRole sr = storeDB.getStoreRole(product.getStore(), user); //??????????????????????????????/ //sr.setProductDiscount(product, discount); }