com.google.appengine.tools.mapreduce.outputs

Class InMemoryOutput<O>

java.lang.Object

com.google.appengine.tools.mapreduce.Output<O,List<List<O>>>

com.google.appengine.tools.mapreduce.outputs.InMemoryOutput<O>

Type Parameters:

O - type of values accepted by this output

All Implemented Interfaces:

Serializable

public class InMemoryOutput<O>
extends Output<O,List<List<O>>>

An Output that collects all values in memory and returns them on finish(java.util.Collection<? extends com.google.appengine.tools.mapreduce.OutputWriter<O>>). Don't use this unless the entire output is small enough to fit in memory.

Author:

ohler@google.com (Christian Ohler)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
InMemoryOutput()

Method Summary

Methods

Modifier and Type	Method and Description
List<? extends OutputWriter<O>>	createWriters(int numShards) Returns a list of writers, one for each shard, for this output.
List<List<O>>	finish(Collection<? extends OutputWriter<O>> writers) Returns a list of lists where the outer list has one element for each reduce shard, which is a list of the values emitted by that shard, in order.

Methods inherited from class com.google.appengine.tools.mapreduce.Output

getContext, setContext

Methods inherited from class java.lang.Object

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

Constructor Detail

InMemoryOutput

public InMemoryOutput()

Method Detail

createWriters

public List<? extends OutputWriter<O>> createWriters(int numShards)

Description copied from class: Output

Returns a list of writers, one for each shard, for this output.

Specified by:

createWriters in class Output<O,List<List<O>>>

Parameters:

numShards - The number of shards which should be equal to the number of OutputWriters returned.

finish

public List<List<O>> finish(Collection<? extends OutputWriter<O>> writers)

Returns a list of lists where the outer list has one element for each reduce shard, which is a list of the values emitted by that shard, in order.

Specified by:

finish in class Output<O,List<List<O>>>