@Override
  public String execute(HttpServletRequest request) throws ServletException, IOException {

    String courseName = request.getParameter("courseName");

    String coursePlaces = request.getParameter("coursePlaces");

    ShowTeacherCourses showTeacherCourses = new ShowTeacherCourses();

    int places = 0;

    try {
      places = Integer.parseInt(coursePlaces);
    } catch (NumberFormatException e) {
      request.setAttribute("courseName", courseName);
      showTeacherCourses.execute(
          request); // as i want to show message if there is no courses and also want to put into
                    // request list of teachers courses
      request.setAttribute(
          "addCourseMessage", MessageManager.getProperty("message.add.course.faild.places"));
      return PathManager.TEACHER_COURSES;
    }

    AddCourseLogic addCourseLogic = new AddCourseLogic();

    HttpSession session = request.getSession();
    Teacher teacher = (Teacher) session.getAttribute("teacher");

    Course course = new Course(teacher, courseName, places);

    if (!addCourseLogic.validateCourse(course)) {
      request.setAttribute("courseName", courseName);
      showTeacherCourses.execute(request);
      request.setAttribute("addCourseMessage", addCourseLogic.getValidationMessage());
      return PathManager.TEACHER_COURSES;
    }

    addCourseLogic.addCourse(course);

    showTeacherCourses.execute(request);

    return PathManager.TEACHER_COURSES;
  }
 public String execute(HttpServletRequest request) throws ServletException, IOException {
   request.setAttribute("nullPageMessage", MessageManager.getProperty("message.nullpage"));
   return PathManager.INDEX_PAGE;
 }