public void addRow(Row row) {
    if (row == null) {
      throw new NullObjectInsertionException();
    }

    //    if (row.getRoom() != null && row.getRoom().equals(this)) {
    //      throw new ReassignObjectException("This row already assigned to another room");
    //    }

    if (exists(row)) {
      throw new ReassignObjectException();
    }
    rows.add(row);
    row.setRoom(this);
  }