class ImportValidator {

    public String validate()
    {
        String message = null;

        ColumnDefinitionTableModel tableModel = myModel.getDefinitionTableModel();

        boolean hasImport = false;

        for (int i = 0; i < tableModel.getRowCount(); i++)
        {
            ColumnDefinitionRow column = tableModel.getRow(i);
            if (column.isImport())
            {
                hasImport = true;
                break;
            }
        }

        if (!hasImport)
        {
            message = "Must have at least one column selected for import.";
        }

        return message;
    }

    public  ImportValidator(ColumnDefinitionModel model);

}