@Override
  public Object getValueAt(int row, int col) {
    Staff employee = employees.get(row);

    switch (col) {
      case NAME:
        return employee.getName();
      case NATINAL_ID_NUM:
        return employee.getNational_id_num();
      case STAFF_ID:
        return employee.getStaff_id();
      case RANK:
        return employee.getRank();

      case OBJECT_COL:
        return employee;

      default:
        return employee.getName();
    }
  }