Java Reference
In-Depth Information
The EmptyCart Service
The EmptyCart class, like all other services, is also an implementation of the
Service.execute() method. Its execute() method starts its execution when a user selects
the Empty Cart link from the navigation.jsp page. It then gets a reference to the user's
ShoppingCart found in the HttpSession and calls the empty() method. The process is then
forwarded to the named target on the request, which in this case is the previously listed
index.jsp . The source for the EmptyCart service is in Listing 20.11.
L ISTING 20.11
import Service;
import ShoppingCart;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.ServletContext;
public class EmptyCart implements Service {
public EmptyCart() {
implemented method from Service interface
public void execute(HttpServletRequest request,
HttpServletResponse response,
ServletContext context) throws Exception {
// Check the HttpSession for an exist ShoppingCart
HttpSession session = request.getSession();
ShoppingCart cart =
if ( cart != null ) {
// If there was an existing cart empty it
The CheckOut Service
The CheckOut service acts exactly like the EmptyCart service, except the result is forwarded to
the CheckOut.jsp page. This is where you would complete the process by sending the results
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