Package org.jgroups.protocols.tom

Class 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

    • 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 JChannel.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 JChannel.connect(String) will throw an exception

      • stop

        public void stop()
        Description copied from class: Protocol
        This method is called on a JChannel.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. A protocol 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 protocol may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down().
        Overrides:
        down in class Protocol

      • down

        public java.lang.Object down​(Message message)
        Description copied from class: Protocol
        A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it before passing it down.
        Overrides:
        down in class Protocol

      • up

        public java.lang.Object up​(Event evt)
        Description copied from class: Protocol
        An event was received from the protocol below. Usually the current protocol 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

      • up

        public java.lang.Object up​(Message message)
        Description copied from class: Protocol
        A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.
        Overrides:
        up in class Protocol

      • getMessageList

        public java.lang.String getMessageList()

      • enableStats

        public void enableStats​(boolean flag)
        Overrides:
        enableStats 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()