void performColumnFilter(DataSetRow row, RowMetadata metadata) {
final boolean needRefresh = rowMetadata == null || !metadata.equals(rowMetadata);
List<ColumnMetadata> columns = metadata.getColumns();
if (!columns.isEmpty()) {
if (filteredColumns == null || needRefresh) {
filteredColumns = columns.stream().filter(filter).collect(Collectors.toList());
filteredColumnNames =
filteredColumns.stream().map(ColumnMetadata::getId).collect(Collectors.toSet());
}
} else {
// No column in row metadata, guess all type, starting from string columns.
ColumnMetadata.Builder builder = ColumnMetadata.Builder.column().type(Type.STRING);
final int rowSize = row.toArray(DataSetRow.SKIP_TDP_ID).length;
columns = new ArrayList<>(rowSize + 1);
for (int i = 0; i < rowSize; i++) {
final ColumnMetadata newColumn = builder.build();
metadata.addColumn(newColumn);
columns.add(newColumn);
}
filteredColumns = columns;
filteredColumnNames = columns.stream().map(ColumnMetadata::getId).collect(Collectors.toSet());
}
rowMetadata = metadata;
}
