org.apache.hadoop.mapreduce.split

Class JobSplit

java.lang.Object

org.apache.hadoop.mapreduce.split.JobSplit

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class JobSplit
extends Object

This class groups the fundamental classes associated with reading/writing splits. The split information is divided into two parts based on the consumer of the information. The two parts are the split meta information, and the raw split information. The first part is consumed by the JobTracker to create the tasks' locality data structures. The second part is used by the maps at runtime to know what to do! These pieces of information are written to two separate files. The metainformation file is slurped by the JobTracker during job initialization. A map task gets the meta information during the launch and it reads the raw split bytes directly from the file.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JobSplit.SplitMetaInfo This represents the meta information about the task split.
static class	JobSplit.TaskSplitIndex This represents the meta information about the task split that the task gets
static class	JobSplit.TaskSplitMetaInfo This represents the meta information about the task split that the JobTracker creates

Field Summary

Fields

Modifier and Type	Field and Description
static JobSplit.TaskSplitMetaInfo	EMPTY_TASK_SPLIT

Constructor Summary

Constructors

Constructor and Description
JobSplit()

Method Summary

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_TASK_SPLIT

public static final JobSplit.TaskSplitMetaInfo EMPTY_TASK_SPLIT

Constructor Detail

JobSplit

public JobSplit()