org.apache.giraph.combiner

Class SumMessageCombiner<M extends org.apache.hadoop.io.Writable>

java.lang.Object

org.apache.giraph.combiner.SumMessageCombiner<M>

Type Parameters:

M - Message type

All Implemented Interfaces:

MessageCombiner<org.apache.hadoop.io.WritableComparable,M>

public class SumMessageCombiner<M extends org.apache.hadoop.io.Writable>
extends Object
implements MessageCombiner<org.apache.hadoop.io.WritableComparable,M>

Message combiner which sums all messages.

Field Summary

Fields

Modifier and Type	Field and Description
static SumMessageCombiner<org.apache.hadoop.io.DoubleWritable>	DOUBLE DoubleWritable specialization
static SumMessageCombiner<org.apache.hadoop.io.FloatWritable>	FLOAT DoubleWritable specialization
static SumMessageCombiner<org.apache.hadoop.io.IntWritable>	INT IntWritable specialization
static SumMessageCombiner<org.apache.hadoop.io.LongWritable>	LONG LongWritable specialization

Constructor Summary

Constructors

Constructor and Description
SumMessageCombiner(NumericTypeOps<M> typeOps) Constructor

Method Summary

Modifier and Type	Method and Description
void	combine(org.apache.hadoop.io.WritableComparable vertexIndex, M originalMessage, M messageToCombine) Combine messageToCombine with originalMessage, by modifying originalMessage.
M	createInitialMessage() Get the initial message.

Methods inherited from class java.lang.Object

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

Field Detail

DOUBLE

public static final SumMessageCombiner<org.apache.hadoop.io.DoubleWritable> DOUBLE

DoubleWritable specialization

FLOAT

public static final SumMessageCombiner<org.apache.hadoop.io.FloatWritable> FLOAT

DoubleWritable specialization

LONG

public static final SumMessageCombiner<org.apache.hadoop.io.LongWritable> LONG

LongWritable specialization

INT

public static final SumMessageCombiner<org.apache.hadoop.io.IntWritable> INT

IntWritable specialization

Constructor Detail

SumMessageCombiner

public SumMessageCombiner(NumericTypeOps<M> typeOps)

Constructor

Parameters:

typeOps - Value type operations

Method Detail

combine

public void combine(org.apache.hadoop.io.WritableComparable vertexIndex,
                    M originalMessage,
                    M messageToCombine)

Description copied from interface: MessageCombiner

Combine messageToCombine with originalMessage, by modifying originalMessage. Note that the messageToCombine object may be reused by the infrastructure, therefore, you cannot directly use it or any objects from it in original message

Specified by:

combine in interface MessageCombiner<org.apache.hadoop.io.WritableComparable,M extends org.apache.hadoop.io.Writable>

Parameters:

vertexIndex - Index of the vertex getting these messages

originalMessage - The first message which we want to combine; put the result of combining in this message

messageToCombine - The second message which we want to combine (object may be reused - do not reference it or its member objects)

createInitialMessage

public M createInitialMessage()

Description copied from interface: MessageCombiner

Get the initial message. When combined with any other message M, the result should be M.

Specified by:

createInitialMessage in interface MessageCombiner<org.apache.hadoop.io.WritableComparable,M extends org.apache.hadoop.io.Writable>

Returns:

Initial message