Package org.apache.hadoop.mapred

Interface Summary

Interface	Description
InputFormat<K,V>	InputFormat describes the input-specification for a Map-Reduce job.
InputSplit	InputSplit represents the data to be processed by an individual Mapper.
InputSplitWithLocationInfo
JobConfigurable	That what may be configured.
JobContext
MapOutputCollector<K,V>
Mapper<K1,V1,K2,V2>	Maps input key/value pairs to a set of intermediate key/value pairs.
MapRunnable<K1,V1,K2,V2>	Expert: Generic interface for Mappers.
MRConstants	Some handy constants
OutputCollector<K,V>	Collects the <key, value> pairs output by Mappers and Reducers.
OutputFormat<K,V>	OutputFormat describes the output-specification for a Map-Reduce job.
Partitioner<K2,V2>	Partitions the key space.
RawKeyValueIterator	RawKeyValueIterator is an iterator used to iterate over the raw keys and values during sort/merge of intermediate data.
RecordReader<K,V>	RecordReader reads <key, value> pairs from an InputSplit.
RecordWriter<K,V>	RecordWriter writes the output <key, value> pairs to an output file.
Reducer<K2,V2,K3,V3>	Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter	A facility for Map-Reduce applications to report progress and update counters, status information etc.
RunningJob	RunningJob is the user-interface to query for details on a running Map-Reduce job.
SequenceFileInputFilter.Filter	filter interface
ShuffleConsumerPlugin<K,V>	ShuffleConsumerPlugin for serving Reducers.
TaskAttemptContext
TaskUmbilicalProtocol	Protocol that task child process uses to contact its parent process.

Class Summary

Class	Description
BackupStore<K,V>	BackupStore is an utility class that is used to support the mark-reset functionality of values iterator
ClusterStatus	Status information on the current state of the Map-Reduce cluster.
ClusterStatus.BlackListInfo	Class which encapsulates information about a blacklisted tasktracker.
Counters	A set of named counters.
Counters.Counter	A counter record, comprising its name and value.
Counters.Group	Group of counters, comprising of counters from a particular counter Enum class.
FileInputFormat<K,V>	A base class for file-based InputFormat.
FileOutputCommitter	An OutputCommitter that commits files specified in job output directory i.e.
FileOutputFormat<K,V>	A base class for OutputFormat.
FileSplit	A section of an input file.
FixedLengthInputFormat	FixedLengthInputFormat is an input format used to read input files which contain fixed length records.
FixedLengthRecordReader	A reader to read fixed length records from a split.
ID	A general identifier, which internally stores the id as an integer.
IFile	IFile is the simple <key-len, value-len, key, value> format for the intermediate map-outputs in Map-Reduce.
IFile.Reader<K,V>	IFile.Reader to read intermediate map-outputs.
IFile.Writer<K,V>	IFile.Writer to write out intermediate map-outputs.
IFileInputStream	A checksum input stream, used for IFiles.
IFileOutputStream	A Checksum output stream.
IndexRecord
JobACLsManager
JobClient	JobClient is the primary interface for the user-job to interact with the cluster.
JobConf	A map/reduce job configuration.
JobContextImpl
JobEndNotifier
JobID	JobID represents the immutable and unique identifier for the job.
JobInProgress
JobProfile	A JobProfile is a MapReduce primitive.
JobQueueInfo	Class that contains the information regarding the Job Queues which are maintained by the Hadoop Map/Reduce framework.
JobStatus	Describes the current status of a job.
JobTracker	JobTracker is no longer used since M/R 2.x.
JvmTask	Task abstraction that can be serialized, implements the writable interface.
KeyValueLineRecordReader	This class treats a line in the input as a key/value pair separated by a separator character.
KeyValueTextInputFormat	An InputFormat for plain text files.
LineRecordReader	Treats keys as offset in file and value as line.
LineRecordReader.LineReader	Deprecated Use LineReader instead.
LocatedFileStatusFetcher	Utility class to fetch block locations for specified Input paths using a configured number of threads.
MapFileOutputFormat	An OutputFormat that writes MapFiles.
MapOutputCollector.Context
MapOutputFile	Manipulate the working area for the transient store for maps and reduces.
MapReduceBase	Base class for Mapper and Reducer implementations.
MapRunner<K1,V1,K2,V2>	Default MapRunnable implementation.
MapTask	A Map task.
MapTask.MapOutputBuffer<K,V>
MapTaskCompletionEventsUpdate	A class that represents the communication between the tasktracker and child tasks w.r.t the map task completion events.
Master
Merger	Merger is an utility class used by the Map and Reduce tasks for merging both their memory and disk segments
Merger.Segment<K,V>
MROutputFiles	Manipulate the working area for the transient store for maps and reduces.
MultiFileInputFormat<K,V>	An abstract InputFormat that returns MultiFileSplit's in MultiFileInputFormat.getSplits(JobConf, int) method.
MultiFileSplit	A sub-collection of input files.
OutputCommitter	OutputCommitter describes the commit of task output for a Map-Reduce job.
OutputLogFilter	This class filters log files from directory given It doesnt accept paths having _logs.
PeriodicStatsAccumulator	This abstract class that represents a bucketed series of measurements of a quantity being measured in a running task attempt.
ProgressSplitsBlock
QueueManager	Class that exposes information about queues maintained by the Hadoop Map/Reduce framework.
ReduceTask	A Reduce task.
SequenceFileAsBinaryInputFormat	InputFormat reading keys, values from SequenceFiles in binary (raw) format.
SequenceFileAsBinaryInputFormat.SequenceFileAsBinaryRecordReader	Read records from a SequenceFile as binary (raw) bytes.
SequenceFileAsBinaryOutputFormat	An OutputFormat that writes keys, values to SequenceFiles in binary(raw) format
SequenceFileAsBinaryOutputFormat.WritableValueBytes	Inner class used for appendRaw
SequenceFileAsTextInputFormat	This class is similar to SequenceFileInputFormat, except it generates SequenceFileAsTextRecordReader which converts the input keys and values to their String forms by calling toString() method.
SequenceFileAsTextRecordReader	This class converts the input keys and values to their String forms by calling toString() method.
SequenceFileInputFilter<K,V>	A class that allows a map/red job to work on a sample of sequence files.
SequenceFileInputFilter.FilterBase	base class for Filters
SequenceFileInputFilter.MD5Filter	This class returns a set of records by examing the MD5 digest of its key against a filtering frequency f.
SequenceFileInputFilter.PercentFilter	This class returns a percentage of records The percentage is determined by a filtering frequency f using the criteria record# % f == 0.
SequenceFileInputFilter.RegexFilter	Records filter by matching key to regex
SequenceFileInputFormat<K,V>	An InputFormat for SequenceFiles.
SequenceFileOutputFormat<K,V>	An OutputFormat that writes SequenceFiles.
SequenceFileRecordReader<K,V>	An RecordReader for SequenceFiles.
ShuffleConsumerPlugin.Context<K,V>
SkipBadRecords	Utility class for skip bad records functionality.
SpillRecord
SplitLocationInfo
Task	Base class for tasks.
Task.CombineOutputCollector<K,V>	OutputCollector for the combiner.
Task.CombinerRunner<K,V>
Task.CombineValuesIterator<KEY,VALUE>	Iterator to return Combined values
Task.NewCombinerRunner<K,V>
Task.OldCombinerRunner<K,V>
TaskAttemptContextImpl
TaskAttemptID	TaskAttemptID represents the immutable and unique identifier for a task attempt.
TaskCompletionEvent	This is used to track task completion events on job tracker.
TaskID	TaskID represents the immutable and unique identifier for a Map or Reduce Task.
TaskLog	A simple logger to handle the task-specific user logs.
TaskLog.Reader
TaskLogAppender	A simple log4j-appender for the task child's map-reduce system logs.
TaskReport	A report on the state of a task.
TaskStatus	Describes the current status of a task.
TextInputFormat	An InputFormat for plain text files.
TextOutputFormat<K,V>	An OutputFormat that writes plain text files.
TextOutputFormat.LineRecordWriter<K,V>
Utils	A utility class.
Utils.OutputFileUtils
Utils.OutputFileUtils.OutputFilesFilter	This class filters output(part) files from the given directory It does not accept files with filenames _logs and _SUCCESS.
Utils.OutputFileUtils.OutputLogFilter	This class filters log files from directory given It doesnt accept paths having _logs.

Enum Summary

Enum	Description
FileInputFormat.Counter	Deprecated
FileOutputFormat.Counter	Deprecated
JobClient.TaskStatusFilter
JobInProgress.Counter	Deprecated Provided for compatibility.
JobPriority	Used to describe the priority of the running job.
JobTracker.State	State is no longer used since M/R 2.x.
Master.State
Operation	Generic operation that maps to the dependent set of ACLs that drive the authorization of the operation.
QueueACL	Enum representing an AccessControlList that drives set of operations that can be performed on a queue.
Task.Counter	Deprecated Provided for compatibility.
TaskCompletionEvent.Status
TaskLog.LogName	The filter for userlogs.
TaskStatus.Phase
TaskStatus.State
TIPStatus	The states of a Tasks.

Exception Summary

Exception	Description
Counters.CountersExceededException	Counter exception thrown when the number of counters exceed the limit
FileAlreadyExistsException	Used when target file already exists for any operation and is not configured to be overwritten.
InvalidFileTypeException	Used when file type differs from the desired file type.
InvalidInputException	This class wraps a list of problems with the input, so that the user can get a list of problems together instead of finding and fixing them one by one.
InvalidJobConfException	This exception is thrown when jobconf misses some mendatory attributes or value of some attributes is invalid.