org.apache.hadoop.mapreduce
Class MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

java.lang.Object
  org.apache.hadoop.mapreduce.JobContext
      org.apache.hadoop.mapreduce.TaskAttemptContext
          org.apache.hadoop.mapreduce.TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
              org.apache.hadoop.mapreduce.MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Type Parameters:

KEYIN - the key input type to the Mapper

VALUEIN - the value input type to the Mapper

KEYOUT - the key output type from the Mapper

VALUEOUT - the value output type from the Mapper

All Implemented Interfaces:

Progressable

Direct Known Subclasses:

Mapper.Context

public class MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
extends TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

The context that is given to the Mapper.

Field Summary

Fields inherited from class org.apache.hadoop.mapreduce.JobContext

CACHE_ARCHIVES_VISIBILITIES, CACHE_FILE_VISIBILITIES, COMBINE_CLASS_ATTR, conf, credentials, INPUT_FORMAT_CLASS_ATTR, JOB_ACL_MODIFY_JOB, JOB_ACL_VIEW_JOB, JOB_CANCEL_DELEGATION_TOKEN, JOB_NAMENODES, MAP_CLASS_ATTR, OUTPUT_FORMAT_CLASS_ATTR, PARTITIONER_CLASS_ATTR, REDUCE_CLASS_ATTR, ugi, USER_LOG_RETAIN_HOURS

Constructor Summary

MapContext(Configuration conf, TaskAttemptID taskid, RecordReader<KEYIN,VALUEIN> reader, RecordWriter<KEYOUT,VALUEOUT> writer, OutputCommitter committer, StatusReporter reporter, InputSplit split)

Method Summary

KEYIN	getCurrentKey() Get the current key.
VALUEIN	getCurrentValue() Get the current value.
InputSplit	getInputSplit() Get the input split for this map.
boolean	nextKeyValue() Advance to the next key, value pair, returning null if at end.

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

getCounter, getCounter, getOutputCommitter, progress, setStatus, write

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

getStatus, getTaskAttemptID

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

getCombinerClass, getConfiguration, getCredentials, getGroupingComparator, getInputFormatClass, getJar, getJobID, getJobName, getMapOutputKeyClass, getMapOutputValueClass, getMapperClass, getNumReduceTasks, getOutputFormatClass, getOutputKeyClass, getOutputValueClass, getPartitionerClass, getReducerClass, getSortComparator, getWorkingDirectory

Methods inherited from class java.lang.Object

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

Constructor Detail

MapContext

public MapContext(Configuration conf,
                  TaskAttemptID taskid,
                  RecordReader<KEYIN,VALUEIN> reader,
                  RecordWriter<KEYOUT,VALUEOUT> writer,
                  OutputCommitter committer,
                  StatusReporter reporter,
                  InputSplit split)

Method Detail

getInputSplit

public InputSplit getInputSplit()

Get the input split for this map.

getCurrentKey

public KEYIN getCurrentKey()
                    throws IOException,
                           InterruptedException

Description copied from class: TaskInputOutputContext

Get the current key.

Specified by:

getCurrentKey in class TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Returns:

the current key object or null if there isn't one

Throws:

IOException

InterruptedException

getCurrentValue

public VALUEIN getCurrentValue()
                        throws IOException,
                               InterruptedException

Description copied from class: TaskInputOutputContext

Get the current value.

Specified by:

getCurrentValue in class TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Returns:

the value object that was read into

Throws:

IOException

InterruptedException

nextKeyValue

public boolean nextKeyValue()
                     throws IOException,
                            InterruptedException

Description copied from class: TaskInputOutputContext

Advance to the next key, value pair, returning null if at end.

Specified by:

nextKeyValue in class TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Returns:

the key object that was read into, or null if no more

Throws:

IOException

InterruptedException