org.apache.hadoop.mapred

Interface ShuffleConsumerPlugin

All Known Implementing Classes:

ReduceTask.ReduceCopier

@InterfaceAudience.LimitedPrivate(value="MapReduce")
@InterfaceStability.Unstable
public interface ShuffleConsumerPlugin

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	ShuffleConsumerPlugin.Context

Method Summary

Methods

Modifier and Type	Method and Description
void	close() close and clean any resource associated with this object.
RawKeyValueIterator	createKVIterator() To create a key-value iterator to read the merged output.
boolean	fetchOutputs() To fetch the map outputs.
Throwable	getMergeThrowable() To get any exception from merge.
void	init(ShuffleConsumerPlugin.Context context) To initialize the reduce copier plugin.

Method Detail

init

void init(ShuffleConsumerPlugin.Context context)
          throws ClassNotFoundException,
                 IOException

To initialize the reduce copier plugin.

Parameters:

context - reduce copier context.

Throws:

ClassNotFoundException

IOException

fetchOutputs

boolean fetchOutputs()
                     throws IOException

To fetch the map outputs.

Returns:

true if the fetch was successful; false otherwise.

Throws:

IOException

createKVIterator

RawKeyValueIterator createKVIterator()
                                     throws IOException

To create a key-value iterator to read the merged output.

Returns:

an iterator for merged key-value pairs.

Throws:

IOException

close

void close()

close and clean any resource associated with this object.

getMergeThrowable

Throwable getMergeThrowable()

To get any exception from merge.