Package org.apache.hadoop.mapred

Interface Summary
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.
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
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.
ID A general identifier, which internally stores the id as an integer.
IFile IFile is the simple 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.
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.
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  
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
JobClient.TaskStatusFilter  
JobInProgress.Counter Deprecated. Provided for compatibility.
JobPriority Used to describe the priority of the running job.
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
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.
 



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