Using an exposed domain model - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 309

Let's look at the details of the servlet:

B

The servlet's init() method creates PlaceOrderService and RestaurantReposi-
tory .
The servlet validates the parameters and creates the delivery address and delivery
time objects.

C

D
E
F
G

It gets the pending order ID from the HttpSession .
The servlet invokes PlaceOrderService.updateDeliveryInfo() .
The servlet stores the pending order ID in the HttpSession .
It selects the JSP page to use to generate the response based on the outcome of
calling the PlaceOrder . For example, if the call to updateDeliveryInfo() succeeds,
the servlet calls displayAvailableRestaurants() .
The displayAvailableRestaurant() method retrieves the list of available restau-
rants by calling RestaurantRepository .
The displayAvailableRestaurant() method forwards the request to the JSP page
availableRestaurants.jsp, passing PendingOrder and the list of restaurants as
HttpServletRequest attributes.
The other servlets are similar. They validate the request parameters, invoke the
PlaceOrderService , and forward the request to a JSP page.

H

I

8.4.2 JSP page design

The JSP pages generate HTML using the domain objects passed to them by the serv-
lets. Each JSP page navigates the object graph and displays the properties of domain
objects. Here is an excerpt of the JSP page that displays the available restaurants:

<%@ page import="net.chrisrichardson.foodToGo.domain.*,
bbbbbbbbbbb b ➥ java.util.*" %>

<%
PendingOrder pendingOrder =
(PendingOrder)request.getAttribute("pendingOrder");
List restaurants = (List)request.getAttribute("restaurants");
%>
…
This excerpt shows how the JSP page gets the PendingOrder and the list of restau-
rants from the HttpServletRequest . It then uses them to generate the HTML
response. The other JSP pages are similar.