protected IColumn computeNext() {
if (reader == null) return endOfData();
while (true) {
IColumn column = reader.pollColumn();
if (column == null) return endOfData();
if (isColumnNeeded(column)) return column;
}
}
public void close() throws IOException {
if (reader != null) reader.close();
}
public ColumnFamily getColumnFamily() {
return reader == null ? null : reader.getEmptyColumnFamily();
}