org.apache.hadoop.mapreduce
Interface TaskInputOutputContext<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 Superinterfaces:

JobContext, org.apache.hadoop.mapreduce.MRJobConfig, Progressable, TaskAttemptContext

All Known Subinterfaces:

MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>, ReduceContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
extends TaskAttemptContext

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

Field Summary

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

APPLICATION_ATTEMPT_ID, APPLICATION_MASTER_CLASS, CACHE_ARCHIVES, CACHE_ARCHIVES_SIZES, CACHE_ARCHIVES_TIMESTAMPS, CACHE_ARCHIVES_VISIBILITIES, CACHE_FILE_TIMESTAMPS, CACHE_FILE_VISIBILITIES, CACHE_FILES, CACHE_FILES_SIZES, CACHE_LOCALARCHIVES, CACHE_LOCALFILES, CACHE_SYMLINK, CLASSPATH_ARCHIVES, CLASSPATH_FILES, COMBINE_CLASS_ATTR, COMBINE_RECORDS_BEFORE_PROGRESS, COMBINER_GROUP_COMPARATOR_CLASS, COMPLETED_MAPS_FOR_REDUCE_SLOWSTART, COUNTER_GROUP_NAME_MAX_DEFAULT, COUNTER_GROUP_NAME_MAX_KEY, COUNTER_GROUPS_MAX_DEFAULT, COUNTER_GROUPS_MAX_KEY, COUNTER_NAME_MAX_DEFAULT, COUNTER_NAME_MAX_KEY, COUNTERS_MAX_DEFAULT, COUNTERS_MAX_KEY, DEFAULT_JOB_ACL_MODIFY_JOB, DEFAULT_JOB_ACL_VIEW_JOB, DEFAULT_JOB_AM_ACCESS_DISABLED, DEFAULT_JOB_TOKEN_TRACKING_IDS_ENABLED, DEFAULT_LOG_LEVEL, DEFAULT_MAP_CPU_VCORES, DEFAULT_MAP_MEMORY_MB, DEFAULT_MAPRED_ADMIN_JAVA_OPTS, DEFAULT_MAPRED_ADMIN_USER_ENV, DEFAULT_MAPREDUCE_APPLICATION_CLASSPATH, DEFAULT_MAPREDUCE_CROSS_PLATFORM_APPLICATION_CLASSPATH, DEFAULT_MAPREDUCE_JOB_EMIT_TIMELINE_DATA, DEFAULT_MAX_ALLOWED_FETCH_FAILURES_FRACTION, DEFAULT_MAX_FETCH_FAILURES_NOTIFICATIONS, DEFAULT_MAX_SHUFFLE_FETCH_HOST_FAILURES, DEFAULT_MAX_SHUFFLE_FETCH_RETRY_DELAY, DEFAULT_MR_AM_ADMIN_COMMAND_OPTS, DEFAULT_MR_AM_COMMAND_OPTS, DEFAULT_MR_AM_COMMIT_WINDOW_MS, DEFAULT_MR_AM_COMMITTER_CANCEL_TIMEOUT_MS, DEFAULT_MR_AM_CONTAINERLAUNCHER_THREAD_COUNT_LIMIT, DEFAULT_MR_AM_CPU_VCORES, DEFAULT_MR_AM_HISTORY_COMPLETE_EVENT_FLUSH_TIMEOUT_MS, DEFAULT_MR_AM_HISTORY_JOB_COMPLETE_UNFLUSHED_MULTIPLIER, DEFAULT_MR_AM_HISTORY_MAX_UNFLUSHED_COMPLETE_EVENTS, DEFAULT_MR_AM_HISTORY_USE_BATCHED_FLUSH_QUEUE_SIZE_THRESHOLD, DEFAULT_MR_AM_IGNORE_BLACKLISTING_BLACKLISTED_NODE_PERCENT, DEFAULT_MR_AM_JOB_CLIENT_THREAD_COUNT, DEFAULT_MR_AM_JOB_REDUCE_PREEMPTION_LIMIT, DEFAULT_MR_AM_JOB_REDUCE_RAMP_UP_LIMIT, DEFAULT_MR_AM_LOG_BACKUPS, DEFAULT_MR_AM_LOG_KB, DEFAULT_MR_AM_LOG_LEVEL, DEFAULT_MR_AM_MAX_ATTEMPTS, DEFAULT_MR_AM_NUM_PROGRESS_SPLITS, DEFAULT_MR_AM_PROFILE, DEFAULT_MR_AM_STAGING_DIR, DEFAULT_MR_AM_TASK_ESTIMATOR_SMOOTH_LAMBDA_MS, DEFAULT_MR_AM_TASK_LISTENER_THREAD_COUNT, DEFAULT_MR_AM_TO_RM_HEARTBEAT_INTERVAL_MS, DEFAULT_MR_AM_TO_RM_WAIT_INTERVAL_MS, DEFAULT_MR_AM_VMEM_MB, DEFAULT_MR_CLIENT_MAX_RETRIES, DEFAULT_MR_CLIENT_TO_AM_IPC_MAX_RETRIES, DEFAULT_MR_CLIENT_TO_AM_IPC_MAX_RETRIES_ON_TIMEOUTS, DEFAULT_MR_ENCRYPTED_INTERMEDIATE_DATA, DEFAULT_MR_ENCRYPTED_INTERMEDIATE_DATA_BUFFER_KB, DEFAULT_MR_ENCRYPTED_INTERMEDIATE_DATA_KEY_SIZE_BITS, DEFAULT_MR_JOB_END_NOTIFICATION_TIMEOUT, DEFAULT_MR_JOB_REDUCER_PREEMPT_DELAY_SEC, DEFAULT_REDUCE_CPU_VCORES, DEFAULT_REDUCE_MEMORY_MB, DEFAULT_SHELL, DEFAULT_SHUFFLE_FETCH_RETRY_INTERVAL_MS, DEFAULT_SHUFFLE_INPUT_BUFFER_PERCENT, DEFAULT_SPLIT_METAINFO_MAXSIZE, DEFAULT_TASK_LOG_BACKUPS, DEFAULT_TASK_PROFILE_PARAMS, GROUP_COMPARATOR_CLASS, HADOOP_WORK_DIR, ID, INDEX_CACHE_MEMORY_LIMIT, INPUT_FORMAT_CLASS_ATTR, IO_SORT_FACTOR, IO_SORT_MB, JAR, JAR_UNPACK_PATTERN, JOB_ACL_MODIFY_JOB, JOB_ACL_VIEW_JOB, JOB_AM_ACCESS_DISABLED, JOB_CANCEL_DELEGATION_TOKEN, JOB_CONF_FILE, JOB_JAR, JOB_JOBTRACKER_ID, JOB_LOCAL_DIR, JOB_NAME, JOB_NAMENODES, JOB_SPLIT, JOB_SPLIT_METAINFO, JOB_SUBMIT_DIR, JOB_SUBMITHOST, JOB_SUBMITHOSTADDR, JOB_TAGS, JOB_TOKEN_TRACKING_IDS, JOB_TOKEN_TRACKING_IDS_ENABLED, JOB_UBERTASK_ENABLE, JOB_UBERTASK_MAXBYTES, JOB_UBERTASK_MAXMAPS, JOB_UBERTASK_MAXREDUCES, JVM_NUMTASKS_TORUN, KEY_COMPARATOR, MAP_CLASS_ATTR, MAP_COMBINE_MIN_SPILLS, MAP_CPU_VCORES, MAP_DEBUG_SCRIPT, MAP_ENV, MAP_FAILURES_MAX_PERCENT, MAP_INPUT_FILE, MAP_INPUT_PATH, MAP_INPUT_START, MAP_JAVA_OPTS, MAP_LOG_LEVEL, MAP_MAX_ATTEMPTS, MAP_MEMORY_MB, MAP_OUTPUT_COLLECTOR_CLASS_ATTR, MAP_OUTPUT_COMPRESS, MAP_OUTPUT_COMPRESS_CODEC, MAP_OUTPUT_KEY_CLASS, MAP_OUTPUT_KEY_FIELD_SEPERATOR, MAP_OUTPUT_VALUE_CLASS, MAP_SKIP_INCR_PROC_COUNT, MAP_SKIP_MAX_RECORDS, MAP_SORT_SPILL_PERCENT, MAP_SPECULATIVE, MAPRED_ADMIN_USER_ENV, MAPRED_ADMIN_USER_SHELL, MAPRED_MAP_ADMIN_JAVA_OPTS, MAPRED_REDUCE_ADMIN_JAVA_OPTS, MAPREDUCE_APPLICATION_CLASSPATH, MAPREDUCE_APPLICATION_FRAMEWORK_PATH, MAPREDUCE_JOB_CLASSLOADER, MAPREDUCE_JOB_CLASSLOADER_SYSTEM_CLASSES, MAPREDUCE_JOB_CREDENTIALS_BINARY, MAPREDUCE_JOB_DIR, MAPREDUCE_JOB_EMIT_TIMELINE_DATA, MAPREDUCE_JOB_LOG4J_PROPERTIES_FILE, MAPREDUCE_JOB_SHUFFLE_PROVIDER_SERVICES, MAPREDUCE_JOB_USER_CLASSPATH_FIRST, MAPREDUCE_V2_CHILD_CLASS, MAX_ALLOWED_FETCH_FAILURES_FRACTION, MAX_FETCH_FAILURES_NOTIFICATIONS, MAX_SHUFFLE_FETCH_HOST_FAILURES, MAX_SHUFFLE_FETCH_RETRY_DELAY, MAX_TASK_FAILURES_PER_TRACKER, MR_AM_ADMIN_COMMAND_OPTS, MR_AM_ADMIN_USER_ENV, MR_AM_COMMAND_OPTS, MR_AM_COMMIT_WINDOW_MS, MR_AM_COMMITTER_CANCEL_TIMEOUT_MS, MR_AM_CONTAINERLAUNCHER_THREAD_COUNT_LIMIT, MR_AM_CPU_VCORES, MR_AM_CREATE_JH_INTERMEDIATE_BASE_DIR, MR_AM_ENV, MR_AM_HISTORY_COMPLETE_EVENT_FLUSH_TIMEOUT_MS, MR_AM_HISTORY_JOB_COMPLETE_UNFLUSHED_MULTIPLIER, MR_AM_HISTORY_MAX_UNFLUSHED_COMPLETE_EVENTS, MR_AM_HISTORY_USE_BATCHED_FLUSH_QUEUE_SIZE_THRESHOLD, MR_AM_IGNORE_BLACKLISTING_BLACKLISTED_NODE_PERECENT, MR_AM_JOB_CLIENT_PORT_RANGE, MR_AM_JOB_CLIENT_THREAD_COUNT, MR_AM_JOB_NODE_BLACKLISTING_ENABLE, MR_AM_JOB_RECOVERY_ENABLE, MR_AM_JOB_RECOVERY_ENABLE_DEFAULT, MR_AM_JOB_REDUCE_PREEMPTION_LIMIT, MR_AM_JOB_REDUCE_RAMPUP_UP_LIMIT, MR_AM_JOB_SPECULATOR, MR_AM_LOG_BACKUPS, MR_AM_LOG_KB, MR_AM_LOG_LEVEL, MR_AM_MAX_ATTEMPTS, MR_AM_NUM_PROGRESS_SPLITS, MR_AM_PREFIX, MR_AM_PROFILE, MR_AM_PROFILE_PARAMS, MR_AM_SECURITY_SERVICE_AUTHORIZATION_CLIENT, MR_AM_SECURITY_SERVICE_AUTHORIZATION_TASK_UMBILICAL, MR_AM_STAGING_DIR, MR_AM_TASK_ESTIMATOR, MR_AM_TASK_ESTIMATOR_EXPONENTIAL_RATE_ENABLE, MR_AM_TASK_ESTIMATOR_SMOOTH_LAMBDA_MS, MR_AM_TASK_LISTENER_THREAD_COUNT, MR_AM_TO_RM_HEARTBEAT_INTERVAL_MS, MR_AM_TO_RM_WAIT_INTERVAL_MS, MR_AM_VMEM_MB, MR_APPLICATION_TYPE, MR_CLIENT_MAX_RETRIES, MR_CLIENT_TO_AM_IPC_MAX_RETRIES, MR_CLIENT_TO_AM_IPC_MAX_RETRIES_ON_TIMEOUTS, MR_ENCRYPTED_INTERMEDIATE_DATA, MR_ENCRYPTED_INTERMEDIATE_DATA_BUFFER_KB, MR_ENCRYPTED_INTERMEDIATE_DATA_KEY_SIZE_BITS, MR_JOB_END_NOTIFICATION_MAX_ATTEMPTS, MR_JOB_END_NOTIFICATION_MAX_RETRY_INTERVAL, MR_JOB_END_NOTIFICATION_PROXY, MR_JOB_END_NOTIFICATION_TIMEOUT, MR_JOB_END_NOTIFICATION_URL, MR_JOB_END_RETRY_ATTEMPTS, MR_JOB_END_RETRY_INTERVAL, MR_JOB_REDUCER_PREEMPT_DELAY_SEC, MR_PREFIX, NUM_MAP_PROFILES, NUM_MAPS, NUM_REDUCE_PROFILES, NUM_REDUCES, OUTPUT, OUTPUT_FORMAT_CLASS_ATTR, OUTPUT_KEY_CLASS, OUTPUT_VALUE_CLASS, PARTITIONER_CLASS_ATTR, PRESERVE_FAILED_TASK_FILES, PRESERVE_FILES_PATTERN, PRIORITY, QUEUE_NAME, RECORDS_BEFORE_PROGRESS, REDUCE_CLASS_ATTR, REDUCE_CPU_VCORES, REDUCE_DEBUG_SCRIPT, REDUCE_ENV, REDUCE_FAILURES_MAXPERCENT, REDUCE_INPUT_BUFFER_PERCENT, REDUCE_JAVA_OPTS, REDUCE_LOG_LEVEL, REDUCE_MARKRESET_BUFFER_PERCENT, REDUCE_MARKRESET_BUFFER_SIZE, REDUCE_MAX_ATTEMPTS, REDUCE_MEMORY_MB, REDUCE_MEMORY_TOTAL_BYTES, REDUCE_MEMTOMEM_ENABLED, REDUCE_MEMTOMEM_THRESHOLD, REDUCE_MERGE_INMEM_THRESHOLD, REDUCE_SKIP_INCR_PROC_COUNT, REDUCE_SKIP_MAXGROUPS, REDUCE_SPECULATIVE, RESERVATION_ID, SETUP_CLEANUP_NEEDED, SHUFFLE_CONNECT_TIMEOUT, SHUFFLE_FETCH_FAILURES, SHUFFLE_FETCH_RETRY_ENABLED, SHUFFLE_FETCH_RETRY_INTERVAL_MS, SHUFFLE_FETCH_RETRY_TIMEOUT_MS, SHUFFLE_INPUT_BUFFER_PERCENT, SHUFFLE_MEMORY_LIMIT_PERCENT, SHUFFLE_MERGE_PERCENT, SHUFFLE_NOTIFY_READERROR, SHUFFLE_PARALLEL_COPIES, SHUFFLE_READ_TIMEOUT, SKIP_OUTDIR, SKIP_RECORDS, SKIP_START_ATTEMPTS, SPECULATIVE_SLOWNODE_THRESHOLD, SPECULATIVE_SLOWTASK_THRESHOLD, SPECULATIVECAP, SPLIT_FILE, SPLIT_METAINFO_MAXSIZE, STDERR_LOGFILE_ENV, STDOUT_LOGFILE_ENV, TASK_ATTEMPT_ID, TASK_CLEANUP_NEEDED, TASK_DEBUGOUT_LINES, TASK_ID, TASK_ISMAP, TASK_LOG_BACKUPS, TASK_MAP_PROFILE_PARAMS, TASK_OUTPUT_DIR, TASK_PARTITION, TASK_PROFILE, TASK_PROFILE_PARAMS, TASK_REDUCE_PROFILE_PARAMS, TASK_TEMP_DIR, TASK_TIMEOUT, TASK_TIMEOUT_CHECK_INTERVAL_MS, TASK_USERLOG_LIMIT, USER_LOG_RETAIN_HOURS, USER_NAME, WORKDIR, WORKFLOW_ADJACENCY_PREFIX_PATTERN, WORKFLOW_ADJACENCY_PREFIX_STRING, WORKFLOW_ID, WORKFLOW_NAME, WORKFLOW_NODE_NAME, WORKFLOW_TAGS, WORKING_DIR

Method Summary

KEYIN	getCurrentKey() Get the current key.
VALUEIN	getCurrentValue() Get the current value.
OutputCommitter	getOutputCommitter() Get the OutputCommitter for the task-attempt.
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 interface org.apache.hadoop.mapreduce.TaskAttemptContext

getCounter, getCounter, getProgress, 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, getProfileTaskRange, getReducerClass, getSortComparator, getSymlink, getTaskCleanupNeeded, getUser, getWorkingDirectory

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

progress

Method Detail

nextKeyValue

boolean nextKeyValue()
                     throws IOException,
                            InterruptedException

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

Returns:

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

Throws:

IOException

InterruptedException

getCurrentKey

KEYIN getCurrentKey()
                    throws IOException,
                           InterruptedException

Get the current key.

Returns:

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

Throws:

IOException

InterruptedException

getCurrentValue

VALUEIN getCurrentValue()
                        throws IOException,
                               InterruptedException

Get the current value.

Returns:

the value object that was read into

Throws:

IOException

InterruptedException

write

void write(KEYOUT key,
           VALUEOUT value)
           throws IOException,
                  InterruptedException

Generate an output key/value pair.

Throws:

IOException

InterruptedException

getOutputCommitter

OutputCommitter getOutputCommitter()

Get the OutputCommitter for the task-attempt.

Returns:

the OutputCommitter for the task-attempt