org.apache.giraph.aggregators

Class LongOverwriteAggregator

java.lang.Object

org.apache.giraph.aggregators.BasicAggregator<org.apache.hadoop.io.LongWritable>

org.apache.giraph.aggregators.LongOverwriteAggregator

All Implemented Interfaces:

Aggregator<org.apache.hadoop.io.LongWritable>

public class LongOverwriteAggregator
extends BasicAggregator<org.apache.hadoop.io.LongWritable>

Aggregator that stores a value that is overwritten once another value is aggregated. This aggregator is useful for one-to-many communication from master.compute() or from a special vertex. In case multiple vertices write to this aggregator, its behavior is non-deterministic.

Constructor Summary

Constructors

Constructor and Description
LongOverwriteAggregator()

Method Summary

Modifier and Type	Method and Description
void	aggregate(org.apache.hadoop.io.LongWritable value) Add a new value.
org.apache.hadoop.io.LongWritable	createInitialValue() Return new aggregated value which is neutral to aggregate operation.

Methods inherited from class org.apache.giraph.aggregators.BasicAggregator

getAggregatedValue, reset, setAggregatedValue

Methods inherited from class java.lang.Object

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

Constructor Detail

LongOverwriteAggregator

public LongOverwriteAggregator()

Method Detail

aggregate

public void aggregate(org.apache.hadoop.io.LongWritable value)

Description copied from interface: Aggregator

Add a new value. Needs to be commutative and associative

Parameters:

value - Value to be aggregated.

createInitialValue

public org.apache.hadoop.io.LongWritable createInitialValue()

Description copied from interface: Aggregator

Return new aggregated value which is neutral to aggregate operation. Must be changeable without affecting internals of Aggregator

Returns:

Neutral value