org.apache.spark
Class NarrowDependency<T>

Object
  org.apache.spark.Dependency<T>
      org.apache.spark.NarrowDependency<T>

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

OneToOneDependency, RangeDependency

public abstract class NarrowDependency<T>
extends Dependency<T>

:: DeveloperApi :: Base class for dependencies where each partition of the child RDD depends on a small number of partitions of the parent RDD. Narrow dependencies allow for pipelined execution.

See Also:

Serialized Form

Constructor Summary

NarrowDependency(RDD<T> _rdd)

Method Summary

abstract scala.collection.Seq<Object>	getParents(int partitionId) Get the parent partitions for a child partition.
RDD<T>	rdd()

Methods inherited from class Object

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

Constructor Detail

NarrowDependency

public NarrowDependency(RDD<T> _rdd)

Method Detail

getParents

public abstract scala.collection.Seq<Object> getParents(int partitionId)

Get the parent partitions for a child partition.

Parameters:

partitionId - a partition of the child RDD

Returns:

the partitions of the parent RDD that the child partition depends upon

rdd

public RDD<T> rdd()

Specified by:

rdd in class Dependency<T>