io.cdap.cdap.api.dataset.lib.partitioned

Class KVTableStatePersistor

java.lang.Object

io.cdap.cdap.api.dataset.lib.partitioned.KVTableStatePersistor

All Implemented Interfaces:

DatasetStatePersistor

public class KVTableStatePersistor
extends Object
implements DatasetStatePersistor

An implementation of DatasetStatePersistor that uses a row of a KeyValueTable for persistence.

Constructor Summary

Constructors

Constructor and Description
KVTableStatePersistor(String kvTableName, String rowKey)

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)

Methods inherited from class java.lang.Object

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

Constructor Detail

KVTableStatePersistor

public KVTableStatePersistor(String kvTableName,
                             String rowKey)

Method Detail

readState

public byte[] readState(DatasetContext datasetContext)

Specified by:

readState in interface DatasetStatePersistor

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

public void persistState(DatasetContext datasetContext,
                         byte[] state)

Description copied from interface: DatasetStatePersistor

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).

Specified by:

persistState in interface DatasetStatePersistor

Parameters:

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

state - the bytes to persist