rice.scribe.messaging
Class MessageHeartBeat

java.lang.Object
  rice.pastry.messaging.Message
      rice.scribe.messaging.ScribeMessage
          rice.scribe.messaging.MessageHeartBeat

All Implemented Interfaces:

java.io.Serializable

public class MessageHeartBeat

extends ScribeMessage

implements java.io.Serializable

HeartBeatMessage is used whenever a Scribe nodes wishes let its children know that it is still alive, so that the children need not do any repairing of the multicast tree. We send a single HeartBeat Message to a node when it is our child for more than one topic, thereby avoiding sending multiple HeartBeat messages to same node.

See Also:

Serialized Form

Field Summary

Fields inherited from class rice.scribe.messaging.ScribeMessage

m_source, m_topicId

Constructor Summary

MessageHeartBeat(Address addr, NodeHandle source, Credentials c)
Constructor

Method Summary

void	handleDeliverMessage(Scribe scribe, Topic tp) This method is called whenever the scribe node receives a message for itself and wants to process it.
boolean	handleForwardMessage(Scribe scribe, Topic topic) This method is called whenever the scribe node forwards a message in the scribe network.
java.lang.String	toString()

Methods inherited from class rice.scribe.messaging.ScribeMessage

getData, getSource, getTopicId, setData

Methods inherited from class rice.pastry.messaging.Message

getCredentials, getDate, getDestination, getSenderId, getStream, hasPriority, setPriority, setSenderId, stamp

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageHeartBeat

public MessageHeartBeat(Address addr,
                        NodeHandle source,
                        Credentials c)

Constructor

Parameters:

addr - the address of the scribe receiver.

source - the node generating the message.

c - the credentials associated with the mesasge.

Method Detail

handleDeliverMessage

public void handleDeliverMessage(Scribe scribe,
                                 Topic tp)

This method is called whenever the scribe node receives a message for itself and wants to process it. The processing is delegated by scribe to the message. If a node has a common parent for some number of topics, then it is going to receive a common HeartBeat message for all those topics. So, it will find out all topics for which this message's source is its parent and consider this message as a HeartBeat message for all those topics.

Specified by:

handleDeliverMessage in class ScribeMessage

Parameters:

scribe - the scribe application.

tp - the dummy topic ( = null), used because MessageHeartBeat extends ScribeMessage.

handleForwardMessage

public boolean handleForwardMessage(Scribe scribe,
                                    Topic topic)

This method is called whenever the scribe node forwards a message in the scribe network. The processing is delegated by scribe to the message.

Specified by:

handleForwardMessage in class ScribeMessage

Parameters:

scribe - the scribe application.

topic - the Topic is null here

Returns:

true if the message should be routed further, false otherwise.

toString

public java.lang.String toString()

Specified by:

toString in class ScribeMessage