org.apache.hadoop.mapreduce.lib.output

Class PathOutputCommitter

java.lang.Object

org.apache.hadoop.mapreduce.OutputCommitter

org.apache.hadoop.mapreduce.lib.output.PathOutputCommitter

Direct Known Subclasses:

org.apache.hadoop.fs.s3a.commit.AbstractS3ACommitter, BindingPathOutputCommitter, FileOutputCommitter

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public abstract class PathOutputCommitter
extends OutputCommitter

A committer which somehow commits data written to a working directory to the final directory during the commit process. The reference implementation of this is the FileOutputCommitter. There are two constructors, both of which do nothing but long and validate their arguments.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PathOutputCommitter(Path outputPath, JobContext context) Constructor for a job attempt.
protected	PathOutputCommitter(Path outputPath, TaskAttemptContext context) Constructor for a task attempt.

Method Summary

Modifier and Type	Method and Description
abstract Path	getOutputPath() Get the final directory where work will be placed once the job is committed.
abstract Path	getWorkPath() Get the directory that the task should write results into.
boolean	hasOutputPath() Predicate: is there an output path?
String	toString()

Methods inherited from class org.apache.hadoop.mapreduce.OutputCommitter

abortJob, abortTask, cleanupJob, commitJob, commitTask, isCommitJobRepeatable, isRecoverySupported, isRecoverySupported, needsTaskCommit, recoverTask, setupJob, setupTask

Methods inherited from class java.lang.Object

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

Constructor Detail

PathOutputCommitter

protected PathOutputCommitter(Path outputPath,
                              TaskAttemptContext context)
                       throws IOException

Constructor for a task attempt. Subclasses should provide a public constructor with this signature.

Parameters:

outputPath - output path: may be null

context - task context

Throws:

IOException - IO problem

PathOutputCommitter

protected PathOutputCommitter(Path outputPath,
                              JobContext context)
                       throws IOException

Constructor for a job attempt. Subclasses should provide a public constructor with this signature.

Parameters:

outputPath - output path: may be null

context - task context

Throws:

IOException - IO problem

Method Detail

getOutputPath

public abstract Path getOutputPath()

Get the final directory where work will be placed once the job is committed. This may be null, in which case, there is no output path to write data to.

Returns:

the path where final output of the job should be placed.

hasOutputPath

public boolean hasOutputPath()

Predicate: is there an output path?

Returns:

true if we have an output path set, else false.

getWorkPath

public abstract Path getWorkPath()
                          throws IOException

Get the directory that the task should write results into. Warning: there's no guarantee that this work path is on the same FS as the final output, or that it's visible across machines. May be null.

Returns:

the work directory

Throws:

IOException - IO problem

toString

public String toString()

Overrides:

toString in class Object