unipg.gila.common.datastructures.messagetypes

Class MessageWritable<P,T>

java.lang.Object

unipg.gila.common.datastructures.messagetypes.MessageWritable<P,T>

Type Parameters:

P - the class of the payload vertex.

T - the class of the value carried by the message.

All Implemented Interfaces:

org.apache.hadoop.io.Writable

Direct Known Subclasses:

DegMessage, LayoutMessage, PartitionMessage

public abstract class MessageWritable<P,T>
extends java.lang.Object
implements org.apache.hadoop.io.Writable

This class represent a message used in the algorithm.

Author:

Alessio Arleo

Field Summary

Fields

Modifier and Type	Field and Description
protected P	payloadVertex
protected int	ttl
protected T	value

Constructor Summary

Constructors

Constructor and Description
MessageWritable() Parameter-less constructor.
MessageWritable(P payloadVertex, int ttl, T value) Constructor setting payload vertex id, value and time to live.
MessageWritable(P payloadVertex, T value) Constructor with only payload vertex id and value.

Method Summary

Methods

Modifier and Type	Method and Description
P	getPayloadVertex() Returns the payload vertex.
int	getTTL() Method that returns the time to live of the message.
T	getValue()
boolean	isAZombie() Method to check if the message should survive or be scrapped.
abstract MessageWritable<P,T>	propagate() This method propagates the message by creating a new MessageWritable and copying the containing values.
abstract MessageWritable<P,T>	propagateAndDie() This method propagates the message by creating a new MessageWritable and copying the containing values.
void	readFields(java.io.DataInput in)
void	setValue(T value)
protected abstract void	specificRead(java.io.DataInput in) Method that guarantees that extending classes are serialized properly.
protected abstract void	specificWrite(java.io.DataOutput out) Method that guarantees that extending classes are de-serialized properly.
void	write(java.io.DataOutput out)

Methods inherited from class java.lang.Object

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

Field Detail

payloadVertex

protected P payloadVertex

ttl

protected int ttl

value

protected T value

Constructor Detail

MessageWritable

public MessageWritable()

Parameter-less constructor.

MessageWritable

public MessageWritable(P payloadVertex,
               int ttl,
               T value)

Constructor setting payload vertex id, value and time to live.

Parameters:

payloadVertex -

ttl -

value -

MessageWritable

public MessageWritable(P payloadVertex,
               T value)

Constructor with only payload vertex id and value. TTL is set to zero.

Parameters:

payloadVertex -

value -

Method Detail

getPayloadVertex

public P getPayloadVertex()

Returns the payload vertex.

Returns:

the payload vertex.

getTTL

public int getTTL()

Method that returns the time to live of the message.

Returns:

the time to live of the message.

getValue

public T getValue()

isAZombie

public boolean isAZombie()

Method to check if the message should survive or be scrapped.

Returns:

Whether or not the message TTL is 0.

propagate

public abstract MessageWritable<P,T> propagate()

This method propagates the message by creating a new MessageWritable and copying the containing values. The returning message will have its time to live diminished.

Returns:

A new MessageWritable with a decreased time to live.

propagateAndDie

public abstract MessageWritable<P,T> propagateAndDie()

This method propagates the message by creating a new MessageWritable and copying the containing values. The returning message will have its time to live zero so that it is scrapped at the next superstep.

Returns:

A new MessageWritable with a decreased time to live equal to zero.

readFields

public void readFields(java.io.DataInput in)
                throws java.io.IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException

setValue

public void setValue(T value)

specificRead

protected abstract void specificRead(java.io.DataInput in)
                              throws java.io.IOException

Method that guarantees that extending classes are serialized properly. All instance variables (excluding the ttl) must be serialized in this method (payloadVertex, value and any other variable introduced). To know more about the serializing process in Hadoop please visit this website.

Parameters:

in -

Throws:

java.io.IOException

specificWrite

protected abstract void specificWrite(java.io.DataOutput out)
                               throws java.io.IOException

Method that guarantees that extending classes are de-serialized properly. All instance variables (excluding the ttl) must be de-serialized in this method (payloadVertex, value and any other variable introduced). To know more about the serializing process in Hadoop please visit this website.

Parameters:

out -

Throws:

java.io.IOException

write

public void write(java.io.DataOutput out)
           throws java.io.IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException