@WebServlet(name = "ControllerServlet",
    loadOnStartup = 1,
    urlPatterns = {
        "/category",
        "/addToCart",
        "/viewCart",
        "/updateCart",
        "/checkout",
        "/purchase",
        "/chooseLanguage"})

@EJB
private CategoryFacade categoryFacade;
@EJB
private OrderManager orderManager;
@Override
public void init() throws ServletException {

    // store category list in servlet context
    getServletContext().setAttribute("categories", categoryFacade.findAll());
}

/**
 * Handles the HTTP <code>GET</code> method.
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

    String userPath = request.getServletPath();

    // if category page is requested
    if (userPath.equals("/category")) {
        // get categoryId from request
        String categoryId = request.getQueryString();

        if (categoryId != null) {
            // get selected category
            Category selectedCategory = categoryFacade.find(Short.parseShort(categoryId));

             // place selected category in request scope
             request.setAttribute("selectedCategory", selectedCategory);
            // get all products for selected category
            Collection<Product> categoryProducts = selectedCategory.getProductCollection();

            // place category products in request scope
            request.setAttribute("categoryProducts", categoryProducts);
        }

    // if cart page is requested
    } else if (userPath.equals("/viewCart")) {
        // TODO: Implement cart page request

        userPath = "/cart";

    // if checkout page is requested
    } else if (userPath.equals("/checkout")) {
        // TODO: Implement checkout page request

    // if user switches language
    } else if (userPath.equals("/chooseLanguage")) {
        // TODO: Implement language request

    }

    // use RequestDispatcher to forward request internally
    String url = "/WEB-INF/view" + userPath + ".jsp";

    try {
        System.out.println("Redirecting to : "+url);
        request.getRequestDispatcher(url).forward(request, response);
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}