Struct MapStructuralEncoder 

pub struct MapStructuralEncoder { /* private fields */ }

A structural encoder for map fields

Map in Arrow is represented as List<Struct<key, value>> The map’s offsets are added to the rep/def builder and the map’s entries (struct array) are passed to the child encoder

Implementations

impl MapStructuralEncoder

pub fn new(keep_original_array: bool, child: Box<dyn FieldEncoder>) -> Self

Trait Implementations

impl FieldEncoder for MapStructuralEncoder

fn maybe_encode( &mut self, array: ArrayRef, external_buffers: &mut OutOfLineBuffers, repdef: RepDefBuilder, row_number: u64, num_rows: u64, ) -> Result<Vec<EncodeTask>>

Buffer the data and, if there is enough data in the buffer to form a page, return an encoding task to encode the data.

fn flush( &mut self, external_buffers: &mut OutOfLineBuffers, ) -> Result<Vec<EncodeTask>>

Flush any remaining data from the buffers into encoding tasks

fn num_columns(&self) -> u32

The number of output columns this encoding will create

fn finish( &mut self, external_buffers: &mut OutOfLineBuffers, ) -> BoxFuture<'_, Result<Vec<EncodedColumn>>>

Finish encoding and return column metadata