protected void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    long id = Utils.longParameterOrDefault(request.getParameter("id"), 0);
    ComputerAndCompanies queryResult = computerDatabaseService.computerByIdAndCompanies(id);

    ComputerForm form = new ComputerForm(queryResult.getComputer());
    request.setAttribute("mode", "edit");
    request.setAttribute("fieldValues", form.getFieldValues());
    request.setAttribute("companies", queryResult.getCompanies());
    request
        .getServletContext()
        .getRequestDispatcher("/WEB-INF/jsp/computer.jsp")
        .forward(request, response);
  }
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    ComputerForm form =
        new ComputerForm(
            request.getParameter("name"),
            request.getParameter("introduced"),
            request.getParameter("discontinued"),
            request.getParameter("company"));

    if (form.isValid()) {
      Computer computer = form.getComputer();
      long id = Utils.longParameterOrDefault(request.getParameter("id"), 0);
      computer.setId(id);
      boolean succesfull =
          computerDatabaseService.updateComputerAndSetCompany(computer, form.getCompanyId());
      if (succesfull) {
        request
            .getSession()
            .setAttribute(
                "alertMessage", "Computer " + computer.getName() + " modified successfully");
      } else {
        request
            .getSession()
            .setAttribute(
                "alertMessage", "There has been a problem while updating " + computer.getName());
      }
      response.sendRedirect("../computers");
    } else {
      request.setAttribute("mode", "edit");
      request.setAttribute("companies", computerDatabaseService.allCompanies());
      request.setAttribute("errorMessages", form.getErrorMessages());
      request.setAttribute("fieldValues", form.getFieldValues());
      request
          .getServletContext()
          .getRequestDispatcher("/WEB-INF/jsp/computer.jsp")
          .forward(request, response);
    }
  }