com.google.appengine.tools.mapreduce.outputs

Class BlobFileOutput

java.lang.Object

com.google.appengine.tools.mapreduce.Output<ByteBuffer,List<com.google.appengine.api.files.AppEngineFile>>

com.google.appengine.tools.mapreduce.outputs.BlobFileOutput

All Implemented Interfaces:

Serializable

public final class BlobFileOutput
extends Output<ByteBuffer,List<com.google.appengine.api.files.AppEngineFile>>

An Output that writes bytes to a set of blob files, one per shard.

Author:

ohler@google.com (Christian Ohler)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BlobFileOutput(String fileNamePattern, String mimeType)

Method Summary

Methods

Modifier and Type	Method and Description
List<BlobFileOutputWriter>	createWriters(int numShards) Returns a list of writers, one for each shard, for this output.
List<com.google.appengine.api.files.AppEngineFile>	finish(Collection<? extends OutputWriter<ByteBuffer>> writers) Returns a list of AppEngineFiles that has one element for each reduce shard.

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

BlobFileOutput

public BlobFileOutput(String fileNamePattern,
              String mimeType)

Method Detail

createWriters

public List<BlobFileOutputWriter> 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<ByteBuffer,List<com.google.appengine.api.files.AppEngineFile>>

Parameters:

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

finish

public List<com.google.appengine.api.files.AppEngineFile> finish(Collection<? extends OutputWriter<ByteBuffer>> writers)

Returns a list of AppEngineFiles that has one element for each reduce shard. Each element is either an AppEngineFile or null (if that reduce shard emitted no data).

Specified by:

finish in class Output<ByteBuffer,List<com.google.appengine.api.files.AppEngineFile>>