org.jgroups.protocols.tom
Class TOA

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.tom.TOA

All Implemented Interfaces:

DeliveryProtocol

public class TOA
extends Protocol
implements DeliveryProtocol

Total Order Anycast with three communication steps (based on Skeen's Algorithm). Establishes total order for a message sent to a subset of the cluster members (an anycast). Example: send a totally ordered message to {D,E} out of a membership of {A,B,C,D,E,F}.

Skeen's algorithm uses consensus among the anycast target members to find the currently highest sequence number (seqno) and delivers the message according to the order established by the seqnos.

Since:

3.1

Author:

Pedro Ruivo

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

TOA()

Method Summary

void	deliver(Message message) deliver a message
java.lang.Object	down(Event evt) An event is to be sent down the stack.
void	enableStats(boolean flag)
double	getAvgDataMessageReceivedDuration()
double	getAvgFinalMessageReceivedDuration()
double	getAvgLastProposeMessageReceivedDuration()
double	getAvgNumberOfUnicastSentPerAnycast()
double	getAvgProposeMessageReceivedDuration()
double	getAvgToaSendDuration()
java.lang.String	getMessageList()
int	getNumberOfAnycastMessagesDelivered()
int	getNumberOfAnycastMessagesSent()
int	getNumberOfDataMessagesDelivered()
int	getNumberOfFinalAnycastSent()
int	getNumberOfFinalMessagesDelivered()
int	getNumberOfProposeMessageReceived()
int	getNumberOfProposeMessageSent()
void	resetStats()
void	start() This method is called on a Channel.connect(String).
void	stop() This method is called on a Channel.disconnect().
java.lang.Object	up(Event evt) An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

destroy, dumpStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, init, isErgonomics, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

TOA

public TOA()

Method Detail

start

public void start()
           throws java.lang.Exception

Description copied from class: Protocol

This method is called on a Channel.connect(String). Starts work. Protocols are connected and queues are ready to receive events. Will be called from bottom to top. This call will replace the START and START_OK events.

Overrides:

start in class Protocol

Throws:

java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception

stop

public void stop()

Description copied from class: Protocol

This method is called on a Channel.disconnect(). Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed

Overrides:

stop in class Protocol

down

public java.lang.Object down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().

Overrides:

down in class Protocol

up

public java.lang.Object up(Event evt)

Description copied from class: Protocol

An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:

up in class Protocol

deliver

public void deliver(Message message)

Description copied from interface: DeliveryProtocol

deliver a message

Specified by:

deliver in interface DeliveryProtocol

Parameters:

message - message to deliver

getMessageList

public java.lang.String getMessageList()

enableStats

public void enableStats(boolean flag)

Overrides:

enableStats in class Protocol

resetStats

public void resetStats()

Overrides:

resetStats in class Protocol

getAvgToaSendDuration

public double getAvgToaSendDuration()

getAvgDataMessageReceivedDuration

public double getAvgDataMessageReceivedDuration()

getAvgProposeMessageReceivedDuration

public double getAvgProposeMessageReceivedDuration()

getAvgLastProposeMessageReceivedDuration

public double getAvgLastProposeMessageReceivedDuration()

getAvgFinalMessageReceivedDuration

public double getAvgFinalMessageReceivedDuration()

getNumberOfAnycastMessagesSent

public int getNumberOfAnycastMessagesSent()

getNumberOfFinalAnycastSent

public int getNumberOfFinalAnycastSent()

getNumberOfAnycastMessagesDelivered

public int getNumberOfAnycastMessagesDelivered()

getNumberOfProposeMessageSent

public int getNumberOfProposeMessageSent()

getNumberOfFinalMessagesDelivered

public int getNumberOfFinalMessagesDelivered()

getNumberOfDataMessagesDelivered

public int getNumberOfDataMessagesDelivered()

getNumberOfProposeMessageReceived

public int getNumberOfProposeMessageReceived()

getAvgNumberOfUnicastSentPerAnycast

public double getAvgNumberOfUnicastSentPerAnycast()