Package org.apache.hadoop.mapreduce

Interface Summary

Interface	Description
Counter	A named counter that tracks the progress of a map/reduce job.
CounterGroup	A group of Counters that logically belong together.
JobContext	A read-only view of the job that is provided to the tasks while they are running.
MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>	The context that is given to the Mapper.
ReduceContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>	The context passed to the Reducer.
TaskAttemptContext	The context for task attempts.
TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>	A context object that allows input and output from the task.

Class Summary

Class	Description
Cluster	Provides a way to access information about the map/reduce cluster.
ClusterMetrics	Status information on the current state of the Map-Reduce cluster.
Counters	Counters holds per job/task counters, defined either by the Map-Reduce framework or applications.
ID	A general identifier, which internally stores the id as an integer.
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.
Job	The job submitter's view of the Job.
JobID	JobID represents the immutable and unique identifier for the job.
JobStatus	Describes the current status of a job.
Mapper<KEYIN,VALUEIN,KEYOUT,VALUEOUT>	Maps input key/value pairs to a set of intermediate key/value pairs.
MarkableIterator<VALUE>	MarkableIterator is a wrapper iterator class that implements the MarkableIteratorInterface.
OutputCommitter	OutputCommitter describes the commit of task output for a Map-Reduce job.
OutputFormat<K,V>	OutputFormat describes the output-specification for a Map-Reduce job.
Partitioner<KEY,VALUE>	Partitions the key space.
QueueAclsInfo	Class to encapsulate Queue ACLs for a particular user.
QueueInfo	Class that contains the information regarding the Job Queues which are maintained by the Hadoop Map/Reduce framework.
RecordReader<KEYIN,VALUEIN>	The record reader breaks the data into key/value pairs for input to the Mapper.
RecordWriter<K,V>	RecordWriter writes the output <key, value> pairs to an output file.
Reducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT>	Reduces a set of intermediate values which share a key to a smaller set of values.
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.
TaskTrackerInfo	Information about TaskTracker.

Enum Summary

Enum	Description
JobCounter
JobPriority	Used to describe the priority of the running job.
QueueState	Enum representing queue state
TaskCompletionEvent.Status
TaskCounter
TaskType	Enum for map, reduce, job-setup, job-cleanup, task-cleanup task types.