Package io.deephaven.extensions.barrage.chunk

Class DictionaryChunkReader

java.lang.Object

io.deephaven.extensions.barrage.chunk.BaseChunkReader<WritableChunk<Values>>

io.deephaven.extensions.barrage.chunk.DictionaryChunkReader

All Implemented Interfaces:

ChunkReader<WritableChunk<Values>>

public class DictionaryChunkReader
extends BaseChunkReader<WritableChunk<Values>>

Reads an Arrow Dictionary-Encoded column from the wire into a flat Deephaven chunk.

The RecordBatch column contains an integer-index array (Int16/Int32/Int64) mapping each row to a position in the dictionary. The dictionary values were received in earlier DictionaryBatch messages and are tracked in the DictionaryReaderRegistry.

This reader consumes one ChunkWriter.FieldNodeInfo (the index column's node) and the corresponding buffers (validity + index values), then expands the indices to the logical value type using the registry.

Nested Class Summary

Nested classes/interfaces inherited from class io.deephaven.extensions.barrage.chunk.BaseChunkReader

BaseChunkReader.ChunkTransformer<READ_CHUNK_TYPE extends Chunk<Values>,DEST_CHUNK_TYPE extends WritableChunk<Values>>

Nested classes/interfaces inherited from interface io.deephaven.extensions.barrage.chunk.ChunkReader

ChunkReader.Factory

Field Summary

Fields inherited from class io.deephaven.extensions.barrage.chunk.BaseChunkReader

BULK_READ_BUFFER_BYTES

Constructor Summary

Constructors

Constructor	Description
DictionaryChunkReader(long dictId, @NotNull ChunkReader<? extends WritableChunk<Values>> indexReader, @NotNull ChunkType valuesChunkType, @NotNull DictionaryReaderRegistry registry)

Method Summary

Modifier and Type	Method	Description
WritableChunk<Values>	readChunk(@NotNull Iterator<ChunkWriter.FieldNodeInfo> fieldNodeIter, PrimitiveIterator.OfLong bufferInfoIter, @NotNull DataInput is, @Nullable WritableChunk<Values> outChunk, int outOffset, int totalRows)	Reads the given DataInput to extract the next Arrow buffer as a Deephaven Chunk.

Methods inherited from class io.deephaven.extensions.barrage.chunk.BaseChunkReader

castOrCreateChunk, getChunkTypeFor, readIntBuffer, readValidityBuffer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.deephaven.extensions.barrage.chunk.ChunkReader

readChunk

Constructor Details

DictionaryChunkReader

public DictionaryChunkReader(long dictId,
 @NotNull
 @NotNull ChunkReader<? extends WritableChunk<Values>> indexReader,
 @NotNull
 @NotNull ChunkType valuesChunkType,
 @NotNull
 @NotNull DictionaryReaderRegistry registry)

Method Details

readChunk

public WritableChunk<Values> readChunk(@NotNull
 @NotNull Iterator<ChunkWriter.FieldNodeInfo> fieldNodeIter,
 @NotNull
 PrimitiveIterator.OfLong bufferInfoIter,
 @NotNull
 @NotNull DataInput is,
 @Nullable
 @Nullable WritableChunk<Values> outChunk,
 int outOffset,
 int totalRows)
                                throws IOException

Description copied from interface: ChunkReader

Reads the given DataInput to extract the next Arrow buffer as a Deephaven Chunk.

Parameters:

fieldNodeIter - iterator to read fields from the stream

bufferInfoIter - iterator to read buffers from the stream

is - input stream containing buffers to be read

outChunk - chunk to write to

outOffset - offset within the outChunk to begin writing

totalRows - total rows to write to the outChunk

Returns:

a Chunk containing the data from the stream

Throws:

IOException - if an error occurred while reading the stream