public void register(IMenu menu) {
   logger.info("menu of " + menu.getTitle() + " is regisered!");
   MenuManager.getInstall().add(menu);
 }
 public void unregister(IMenu menu) {
   logger.info("menu of " + menu.getTitle() + " is unregisered!");
   MenuManager.getInstall().remove(menu);
 }