Foo.java

        String orderId = request.getParam("id");
        String sku = request.getParam("sku");
        Order order = orderDao.findOneById(orderId);
        Item item = itemDao.findOneBySku(sku);

        order.addItem(item);

        double total = 0.0;
        for (Item item : order.getItems()) {
            total += item.getPrice();
        }

        order.setTotalPrice(total);
        order.setLastUpdated(new Date());