org.apache.jena.hadoop.rdf.mapreduce.characteristics

Class AbstractCharacteristicSetGeneratingReducer<TValue,T extends AbstractNodeTupleWritable<TValue>>

java.lang.Object

org.apache.hadoop.mapreduce.Reducer<NodeWritable,T,CharacteristicSetWritable,org.apache.hadoop.io.NullWritable>

org.apache.jena.hadoop.rdf.mapreduce.characteristics.AbstractCharacteristicSetGeneratingReducer<TValue,T>

Type Parameters:

TValue - Tuple type

T - Writable tuple type

Direct Known Subclasses:

QuadCharacteristicSetGeneratingReducer, TripleCharacteristicSetGeneratingReducer

public abstract class AbstractCharacteristicSetGeneratingReducer<TValue,T extends AbstractNodeTupleWritable<TValue>>
extends org.apache.hadoop.mapreduce.Reducer<NodeWritable,T,CharacteristicSetWritable,org.apache.hadoop.io.NullWritable>

Abstract reducer which takes in tuples grouped by some node and generating initial characteristic sets.

This produces the characteristic sets as both the key and value so that in a subsequent job the characteristic steps may be further combined together to total up the usage counts appropriately.

It is important to note that the output from this mapper can be very large and since it typically needs to be written to HDFS before being processed by further jobs it is strongly recommended that you use appropriate output compression

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer

org.apache.hadoop.mapreduce.Reducer.Context

Constructor Summary

Constructors

Constructor and Description
AbstractCharacteristicSetGeneratingReducer()

Method Summary

Methods inherited from class org.apache.hadoop.mapreduce.Reducer

run

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractCharacteristicSetGeneratingReducer

public AbstractCharacteristicSetGeneratingReducer()