org.apache.giraph.combiner

Class NullMessageCombiner

java.lang.Object

org.apache.giraph.combiner.NullMessageCombiner

All Implemented Interfaces:

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

public class NullMessageCombiner
extends Object
implements MessageCombiner<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.NullWritable>

Keeps only one NullMessage.

Constructor Summary

Constructors

Constructor and Description
NullMessageCombiner()

Method Summary

Modifier and Type	Method and Description
void	combine(org.apache.hadoop.io.WritableComparable vertexId, org.apache.hadoop.io.NullWritable null1, org.apache.hadoop.io.NullWritable null2) Combine messageToCombine with originalMessage, by modifying originalMessage.
org.apache.hadoop.io.NullWritable	createInitialMessage() Get the initial message.

Methods inherited from class java.lang.Object

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

Constructor Detail

NullMessageCombiner

public NullMessageCombiner()

Method Detail

combine

public void combine(org.apache.hadoop.io.WritableComparable vertexId,
                    org.apache.hadoop.io.NullWritable null1,
                    org.apache.hadoop.io.NullWritable null2)

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,org.apache.hadoop.io.NullWritable>

Parameters:

vertexId - Index of the vertex getting these messages

null1 - The first message which we want to combine; put the result of combining in this message

null2 - The second message which we want to combine (object may be reused - do not reference it or its member objects)

createInitialMessage

public org.apache.hadoop.io.NullWritable 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,org.apache.hadoop.io.NullWritable>

Returns:

Initial message