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package examples.shop.web.servlet;
import java.io.IOException;
import java.util.Enumeration;
import java.util.List;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import examples.shop.impl.entity.LineItem;
import examples.shop.logic.Cart;
import examples.shop.logic.Pricer;
/**
* This servlet allows the user to view and modify his current selections.
*
* By the time this servlet is called, the user has logged in (via the Login
* servlet), and has a shopping cart started (i.e. cart bean). Since this
* servlet is pooled and re-used for different user requests, the servlet code
* does not store any information specific to any user. Rather, we store a
* reference to the user's cart in the user's HttpSession object, which is
* globally accessible to all servlets.
*/
public class ShowQuoteServlet extends HttpServlet {
// Pricer for pricing the cart
private Pricer pricer;
/**
* The servlet engine calls this method once to initialize a servlet
* instance.
*
* In the body of this method, we need to acquire a Pricer EJB Object for
* pricing the carts.
*/
public void init(ServletConfig config) throws ServletException {
/*
* Call parent to store the config object, so that getServletConfig()
* can return it.
*/
super.init(config);
try {
Context ctx = new InitialContext();
pricer = (Pricer)ctx.lookup(Pricer.class.getName());
} catch (NamingException e) {
e.printStackTrace();
}
}
/**
* The servlet engine calls this method when the user's desktop browser
* sends an HTTP GET request.
*/
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/*
* Get the user's HttpSession, and from that get the user's current
* cart.
*/
HttpSession session = request.getSession(false);
if (session == null) {
/*
* Redirect user to login page if no session
*/
response.sendRedirect(response.encodeRedirectURL("/jasmine/login"));
return;
}
Object obj = session.getAttribute("cart");
if (obj == null) {
/*
* Redirect user to login page if no session
*/
response.sendRedirect(response.encodeRedirectURL("/jasmine/login"));
return;
}
Cart cart = (Cart) obj;
/*
* If the user clicked the 'Order' button, he wants to purchase his
* selections. We forward the user to the servlet that handles
* purchasing.
*/
if (request.getParameter("Order") != null) {
/*
* First, turn the cart into an order
*/
String orderId = cart.purchase();
/*
* Stick the orderID in the request so the JSP gets it
*/
request.setAttribute("orderID", orderId);
cart.clear();
this.getServletContext().getRequestDispatcher("/receipt.jsp")
.forward(request, response);
return;
}
/*
* Next, we need to figure out what button the user clicked, if any.
* These come to us as form parameters. We need to loop through each
* parameter and interpret it.
*/
Enumeration paramNames = request.getParameterNames();
while (paramNames.hasMoreElements()) {
String paramName = (String) paramNames.nextElement();
String paramValue = request.getParameter(paramName);
/*
* If user clicked 'Update' button, then the user wants to change
* the quantities of each product he is ordering. We'll process
* those quantities below.
*/
if (paramName.equals("Update")) {
} else if (paramName.equals("Clear")) {
/*
* The user wants to clear the form
*/
cart.clear();
this.getServletContext()
.getRequestDispatcher("/clearQuote.jsp").forward(
request, response);
return;
} else {
/*
* If the parameter represents a quantity of a particular
* product the user is interested in, then we should update that
* product's quantity to reflect this new value.
*/
try {
/*
* Convert the quantity to int format, and set the new
* quantity
*/
int quantity = Integer.parseInt(paramValue);
cart.modify(paramName, quantity);
} catch (NumberFormatException e) {
throw new ServletException("Bad parameter to servlet: "
+ paramName + ", " + paramValue);
} catch (Exception e) {
throw new ServletException(e.toString());
}
}
}
/*
* Recalculate all totals based upon new quantities
*/
try {
cart.setSubtotal(pricer.priceSubtotal(cart.getOwner(), cart.getAll()));
cart.setTaxes(pricer.priceTaxes(cart.getSubtotal()));
} catch (Exception e) {
log(e);
throw new ServletException(e.toString());
}
/*
* Otherwise, show the current cart again
*/
List<LineItem> lineItems = cart.getAll();
if (lineItems.size() > 0) {
/*
* Stick lineitems, subtotal, taxes and total in request
*/
request.setAttribute("lineItems", lineItems);
request.setAttribute("subTotal", new Double(cart.getSubtotal()));
request.setAttribute("taxes", new Double(cart.getTaxes()));
request.setAttribute("taxRate", new Double(pricer.getTaxRate()));
request.setAttribute("total", new Double(cart.getTotalPrice()));
// Forwards the request to the showQuote JSP.
this.getServletContext().getRequestDispatcher("/showQuote.jsp")
.forward(request, response);
return;
} else {
/*
* If there are no products, print out that the cart is empty.
*/
this.getServletContext().getRequestDispatcher("/emptyQuote.jsp")
.forward(request, response);
return;
}
}
private void log(Exception e) {
e.printStackTrace();
}
public String getServletInfo() {
return "The ShowQuote servlet returns information about"
+ "the products that the user is in the process of ordering.";
}
}
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