com.hazelcast.mapreduce.impl.task
Class DefaultContext<KeyIn,ValueIn>

java.lang.Object
  com.hazelcast.mapreduce.impl.task.DefaultContext<KeyIn,ValueIn>

Type Parameters:

KeyIn -

ValueIn -

All Implemented Interfaces:

Context<KeyIn,ValueIn>

public class DefaultContext<KeyIn,ValueIn>
extends Object
implements Context<KeyIn,ValueIn>

This is the internal default implementation of a map reduce context mappers emit values to. It controls the emitted values to be combined using either the set Combiner or by utilizing the internal collecting combiner (which is just a better HashMap ;-)).
In addition to that it is responsible to notify about an the MapCombineTask about an emitted value to eventually send out chunks on reaching the chunk size limit.

Constructor Summary

protected

DefaultContext(CombinerFactory<KeyIn,ValueIn,?> combinerFactory, MapCombineTask mapCombineTask)

Method Summary

void	emit(KeyIn key, ValueIn value) Emits a key-value pair to the intermediate working space.
<Chunk> Map<KeyIn,Chunk>	finish()
int	getCollected()
Combiner<ValueIn,?>	getOrCreateCombiner(KeyIn key)
<Chunk> Map<KeyIn,Chunk>	requestChunk()
void	setPartitionId(int partitionId)

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultContext

protected DefaultContext(CombinerFactory<KeyIn,ValueIn,?> combinerFactory,
                         MapCombineTask mapCombineTask)

Method Detail

setPartitionId

public void setPartitionId(int partitionId)

emit

public void emit(KeyIn key,
                 ValueIn value)

Description copied from interface: Context

Emits a key-value pair to the intermediate working space. The same key can be used multiple times to collect values under the same key.

Specified by:

emit in interface Context<KeyIn,ValueIn>

Parameters:

key - emitted key.

value - emitted value.

requestChunk

public <Chunk> Map<KeyIn,Chunk> requestChunk()

getCollected

public int getCollected()

finish

public <Chunk> Map<KeyIn,Chunk> finish()

getOrCreateCombiner

public Combiner<ValueIn,?> getOrCreateCombiner(KeyIn key)