@Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        Object value = null;
        Supplier supplier = service.getSuppliers().get(rowIndex);
        switch(columnIndex) {
            case 0: {
                value = supplier.getName();
                break;
            }
            case 1: {
                value = supplier.getHead() == null ? "" : supplier.getHead().getName();
                break;
            }
            case 2: {
                value = supplier.getRegionLocation() == null ? "" : supplier.getRegionLocation().getName();
                break;
            }
            case 3: {
                value = supplier.getRegionTrade() == null ? "" : supplier.getRegionTrade().getName();
                break;
            }
            default:
        }
        return value;
    }