private Vector retrieveLots() {
    List<Lot> lots = DAOProvider.getLotDAO().getAll();
    Vector model = new Vector();
    for (Lot lot : lots) {
      model.add(new Item(lot.getLotId(), lot.getLotId().toString()));
    }

    return model;
  }
  private Vector retrieveSourceParties(String partyType) {
    List<Party> sourceParties = DAOProvider.getPartyDAO().getByType(partyType);
    Vector model = new Vector();
    for (Party party : sourceParties) {
      model.add(new Item(party.getPartyId(), party.getName()));
    }

    return model;
  }