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

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


Copyright © 2009 The Apache Software Foundation