// Handle the adding of a User in the Database
 public void addUserButtonClicked(String nick, String pass, String email) {
   try {
     FU.addUser(nick, pass, email);
   } catch (EmptyFieldsException e) {
     JOptionPane.showMessageDialog(
         null, "Enter a nickname and a password.", "Add a User", JOptionPane.ERROR_MESSAGE);
   } catch (ObjectCreatedException e) {
     if ((addUserRole.getSelectedItem()).equals("Admin")) {
       FU.chooseUserRoleAdmin(nick);
     } else if ((addUserRole.getSelectedItem()).equals("Simple User")) {
       FU.chooseUserRoleSimpleUser(nick);
     } else if ((addUserRole.getSelectedItem()).equals("Seller")) {
       FU.chooseUserRoleSeller(nick);
     }
     JOptionPane.showMessageDialog(
         null,
         nick + " is now registered into the DB !",
         "Add a User",
         JOptionPane.INFORMATION_MESSAGE);
   } catch (ObjectAlreadyExistsException e) {
     JOptionPane.showMessageDialog(
         null, nick + " already exists into the DB.", "Add a User", JOptionPane.ERROR_MESSAGE);
   }
 }