io.cdap.cdap.api.dataset.lib

Interface DatasetStatePersistor

All Known Implementing Classes:

KVTableStatePersistor

public interface DatasetStatePersistor

Defines how some state will be persisted/managed, using a DatasetContext to read and persist state.

Method Summary

Modifier and Type	Method and Description
void	persistState(DatasetContext datasetContext, byte[] state) Writes the serialized bytes of the state of the partition consuming process.
byte[]	readState(DatasetContext datasetContext)

Method Detail

readState

@Nullable
byte[] readState(DatasetContext datasetContext)

Parameters:

datasetContext - context to use to instantiate dataset(s) for reading the state

Returns:

the serialized bytes of the state of the partition consuming process; return null to indicate a fresh state of consuming (defaults to starting from the beginning).

persistState

void persistState(DatasetContext datasetContext,
                  byte[] state)

Writes the serialized bytes of the state of the partition consuming process. The bytes written in this method should be available in the following call to readBytes(DatasetContext).

Parameters:

datasetContext - context to use to instantiate dataset(s) for persisting the state

state - the bytes to persist