org.apache.hadoop.mapreduce.split
Class JobSplit
java.lang.Object
org.apache.hadoop.mapreduce.split.JobSplit
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 |
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 |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
EMPTY_TASK_SPLIT
public static final JobSplit.TaskSplitMetaInfo EMPTY_TASK_SPLIT
JobSplit
public JobSplit()
Copyright © 2009 The Apache Software Foundation