Package io.deephaven.extensions.barrage.chunk

Interface DictionaryWriterRegistry

All Known Implementing Classes:

DictionaryWriterRegistryImpl, WebDictionaryWriterRegistryImpl

public interface DictionaryWriterRegistry

Manages the set of DictionaryWriterState instances for a single barrage stream (snapshot or subscription update sequence), one per Arrow dictionary id.

When BarrageMessageWriterImpl processes a batch, it calls getOrCreate(long, io.deephaven.extensions.barrage.chunk.ChunkWriter<io.deephaven.chunk.Chunk<io.deephaven.chunk.attributes.Values>>, io.deephaven.chunk.ChunkType) for each DictionaryChunkWriter column to obtain (or register) the state for that column's dictionary id. After the batch's column data is serialized, the registry's entries() are inspected to determine which dictionary ids have pending deltas that need a DictionaryBatch message.

The server implementation is DictionaryWriterRegistryImpl. The JS API supplies its own implementation, since the server implementation's fastutil backing is not available under GWT.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	DictionaryWriterRegistry.Entry	Per-id state plus the values writer needed to serialize dictionary values into a DictionaryBatch.

Method Summary

Modifier and Type	Method	Description
@NotNull Collection<DictionaryWriterRegistry.Entry>	entries()	Returns all registered entries.
@NotNull DictionaryWriterState	getOrCreate(long dictId, @NotNull ChunkWriter<Chunk<Values>> valuesWriter, @NotNull ChunkType valuesChunkType)	Returns (or creates) the DictionaryWriterState for the given dictionary id.
boolean	hasAnyDelta()	Returns true if any registered dictionary has a pending delta that needs a DictionaryBatch message.
void	maybeResetEntries(@NotNull LongUnaryOperator maxSizeForDictId)	Resets each registered DictionaryWriterState whose totalSize exceeds the limit maxSizeForDictId gives for its dictionary id, so the next DictionaryBatch will be isDelta=false with a compacted dictionary.
void	resetDeltas()	Advances the delta boundary for every registered state that currently has a pending delta.

Method Details

getOrCreate

@NotNull
@NotNull DictionaryWriterState getOrCreate(long dictId,
 @NotNull
 @NotNull ChunkWriter<Chunk<Values>> valuesWriter,
 @NotNull
 @NotNull ChunkType valuesChunkType)

Returns (or creates) the DictionaryWriterState for the given dictionary id.

The first call for a given dictId registers the valuesWriter for that id and creates the appropriate state type. Subsequent calls for the same id return the existing state.

entries

@NotNull
@NotNull Collection<DictionaryWriterRegistry.Entry> entries()

Returns all registered entries.

hasAnyDelta

boolean hasAnyDelta()

Returns true if any registered dictionary has a pending delta that needs a DictionaryBatch message.

resetDeltas

void resetDeltas()

Advances the delta boundary for every registered state that currently has a pending delta.

maybeResetEntries

void maybeResetEntries(@NotNull
 @NotNull LongUnaryOperator maxSizeForDictId)

Resets each registered DictionaryWriterState whose totalSize exceeds the limit maxSizeForDictId gives for its dictionary id, so the next DictionaryBatch will be isDelta=false with a compacted dictionary. This applies to local (viewport/snapshot) registries only; a shared-backed registry ignores this call, as its SharedWriterDictionary is reset externally.

Parameters:

maxSizeForDictId - the most values the dictionary with a given id may hold before it is reset; typically no more than the live row count visible to the subscription