class DataTable {

    public List<String> getColumn(int c) {
        List<String> result = new ArrayList<>(getRowsCount());
        for (List<String> row : data) {
            result.add(getOrEmpty(row, c));
        }
        return result;
    }

    public  DataTable(int pageNumber);
    public  DataTable(Collection<Integer> pageNumbers);

}