org.apache.hadoop.mapreduce.task

Class TaskInputOutputContextImpl<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

java.lang.Object

org.apache.hadoop.mapreduce.task.JobContextImpl

org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl

org.apache.hadoop.mapreduce.task.TaskInputOutputContextImpl<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Type Parameters:

KEYIN - the input key type for the task

VALUEIN - the input value type for the task

KEYOUT - the output key type for the task

VALUEOUT - the output value type for the task

All Implemented Interfaces:

JobContext, TaskAttemptContext, TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>, org.apache.hadoop.util.Progressable

Direct Known Subclasses:

MapContextImpl, ReduceContextImpl

public abstract class TaskInputOutputContextImpl<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
extends TaskAttemptContextImpl
implements TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

A context object that allows input and output from the task. It is only supplied to the Mapper or Reducer.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl

TaskAttemptContextImpl.DummyReporter

Field Summary

Fields inherited from class org.apache.hadoop.mapreduce.task.JobContextImpl

conf, credentials, ugi

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

CACHE_ARCHIVES_VISIBILITIES, CACHE_FILE_VISIBILITIES, COMBINE_CLASS_ATTR, INPUT_FORMAT_CLASS_ATTR, JAR_UNPACK_PATTERN, JOB_ACL_MODIFY_JOB, JOB_ACL_VIEW_JOB, JOB_CANCEL_DELEGATION_TOKEN, JOB_NAMENODES, MAP_CLASS_ATTR, MAP_MEMORY_PHYSICAL_MB, MAP_OUTPUT_COLLECTOR_CLASS_ATTR, MAPREDUCE_TASK_CLASSPATH_PRECEDENCE, OUTPUT_FORMAT_CLASS_ATTR, PARTITIONER_CLASS_ATTR, REDUCE_CLASS_ATTR, REDUCE_MEMORY_PHYSICAL_MB, SHUFFLE_CONSUMER_PLUGIN_ATTR, USER_LOG_RETAIN_HOURS

Constructor Summary

Constructors

Constructor and Description
TaskInputOutputContextImpl(org.apache.hadoop.conf.Configuration conf, TaskAttemptID taskid, RecordWriter<KEYOUT,VALUEOUT> output, OutputCommitter committer, StatusReporter reporter)

Method Summary

Methods

Modifier and Type	Method and Description
abstract KEYIN	getCurrentKey() Get the current key.
abstract VALUEIN	getCurrentValue() Get the current value.
OutputCommitter	getOutputCommitter() Get the OutputCommitter for the task-attempt.
abstract boolean	nextKeyValue() Advance to the next key, value pair, returning null if at end.
void	write(KEYOUT key, VALUEOUT value) Generate an output key/value pair.

Methods inherited from class org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl

getCounter, getCounter, getStatus, getTaskAttemptID, progress, setStatus, setStatusString

Methods inherited from class org.apache.hadoop.mapreduce.task.JobContextImpl

getArchiveClassPaths, getArchiveTimestamps, getCacheArchives, getCacheFiles, getCombinerClass, getCombinerKeyGroupingComparator, getConfiguration, getCredentials, getFileClassPaths, getFileTimestamps, getGroupingComparator, getInputFormatClass, getJar, getJobID, getJobName, getJobSetupCleanupNeeded, getLocalCacheArchives, getLocalCacheFiles, getMapOutputKeyClass, getMapOutputValueClass, getMapperClass, getMaxMapAttempts, getMaxReduceAttempts, getNumReduceTasks, getOutputFormatClass, getOutputKeyClass, getOutputValueClass, getPartitionerClass, getProfileEnabled, getProfileParams, getProfileTaskRange, getReducerClass, getSortComparator, getSymlink, getUser, getWorkingDirectory, setJobID, userClassesTakesPrecedence

Methods inherited from class java.lang.Object

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

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

getCounter, getCounter, getStatus, getTaskAttemptID, setStatus

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

getArchiveClassPaths, getArchiveTimestamps, getCacheArchives, getCacheFiles, getCombinerClass, getCombinerKeyGroupingComparator, getConfiguration, getCredentials, getFileClassPaths, getFileTimestamps, getGroupingComparator, getInputFormatClass, getJar, getJobID, getJobName, getJobSetupCleanupNeeded, getLocalCacheArchives, getLocalCacheFiles, getMapOutputKeyClass, getMapOutputValueClass, getMapperClass, getMaxMapAttempts, getMaxReduceAttempts, getNumReduceTasks, getOutputFormatClass, getOutputKeyClass, getOutputValueClass, getPartitionerClass, getProfileEnabled, getProfileParams, getReducerClass, getSortComparator, getSymlink, getUser, getWorkingDirectory, userClassesTakesPrecedence

Methods inherited from interface org.apache.hadoop.util.Progressable

progress

Constructor Detail

TaskInputOutputContextImpl

public TaskInputOutputContextImpl(org.apache.hadoop.conf.Configuration conf,
                          TaskAttemptID taskid,
                          RecordWriter<KEYOUT,VALUEOUT> output,
                          OutputCommitter committer,
                          StatusReporter reporter)

Method Detail

nextKeyValue

public abstract boolean nextKeyValue()
                              throws java.io.IOException,
                                     java.lang.InterruptedException

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

Specified by:

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

Returns:

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

Throws:

java.io.IOException

java.lang.InterruptedException

getCurrentKey

public abstract KEYIN getCurrentKey()
                             throws java.io.IOException,
                                    java.lang.InterruptedException

Get the current key.

Specified by:

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

Returns:

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

Throws:

java.io.IOException

java.lang.InterruptedException

getCurrentValue

public abstract VALUEIN getCurrentValue()
                                 throws java.io.IOException,
                                        java.lang.InterruptedException

Get the current value.

Specified by:

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

Returns:

the value object that was read into

Throws:

java.io.IOException

java.lang.InterruptedException

write

public void write(KEYOUT key,
         VALUEOUT value)
           throws java.io.IOException,
                  java.lang.InterruptedException

Generate an output key/value pair.

Specified by:

write in interface TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Throws:

java.io.IOException

java.lang.InterruptedException

getOutputCommitter

public OutputCommitter getOutputCommitter()

Description copied from interface: TaskInputOutputContext

Get the OutputCommitter for the task-attempt.

Specified by:

getOutputCommitter in interface TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

Returns:

the OutputCommitter for the task-attempt