Package org.jgroups.protocols.pbcast

Class NAKACK

  • All Implemented Interfaces:
    NakReceiverWindow.Listener, Retransmitter.RetransmitCommand
    public class NAKACK
extends Protocol
implements Retransmitter.RetransmitCommand, NakReceiverWindow.Listener
    Negative AcKnowledgement layer (NAKs). Messages are assigned a monotonically increasing sequence number (seqno). Receivers deliver messages ordered according to seqno and request retransmission of missing messages.
    Retransmit requests are usually sent to the original sender of a message, but this can be changed by xmit_from_random_member (send to random member) or use_mcast_xmit_req (send to everyone). Responses can also be sent to everyone instead of the requester by setting use_mcast_xmit to true.
    Version:
    $Id: NAKACK.java,v 1.170.2.16.2.6 2009/05/04 14:11:33 belaban Exp $
    Author:
    Bela Ban

    • Field Detail

      • stability_msgs

        protected final BoundedList<Digest> stability_msgs
        BoundedList, keeps the last 10 stability messages

      • merge_history

        protected final BoundedList<java.lang.String> merge_history

      • print_stability_history_on_failed_xmit

        protected boolean print_stability_history_on_failed_xmit
        When not finding a message on an XMIT request, include the last N stability messages in the error message

    • Constructor Detail

      • NAKACK

        public NAKACK()

    • Method Detail

      • getName

        public java.lang.String getName()
        Specified by:
        getName in class Protocol

      • getXmitRequestsReceived

        public long getXmitRequestsReceived()

      • getXmitRequestsSent

        public long getXmitRequestsSent()

      • getXmitResponsesReceived

        public long getXmitResponsesReceived()

      • getXmitResponsesSent

        public long getXmitResponsesSent()

      • getMissingMessagesReceived

        public long getMissingMessagesReceived()

      • getPendingRetransmissionRequests

        public int getPendingRetransmissionRequests()

      • getXmitTableSize

        public int getXmitTableSize()

      • getReceivedTableSize

        public int getReceivedTableSize()

      • init

        public void init()
          throws java.lang.Exception
        Description copied from class: Protocol
        Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
        Overrides:
        init in class Protocol
        Throws:
        java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception

      • getGcLag

        public int getGcLag()

      • setGcLag

        public void setGcLag​(int gc_lag)

      • isUseMcastXmit

        public boolean isUseMcastXmit()

      • setUseMcastXmit

        public void setUseMcastXmit​(boolean use_mcast_xmit)

      • isXmitFromRandomMember

        public boolean isXmitFromRandomMember()

      • setXmitFromRandomMember

        public void setXmitFromRandomMember​(boolean xmit_from_random_member)

      • isDiscardDeliveredMsgs

        public boolean isDiscardDeliveredMsgs()

      • setDiscardDeliveredMsgs

        public void setDiscardDeliveredMsgs​(boolean discard_delivered_msgs)

      • getMaxXmitBufSize

        public int getMaxXmitBufSize()

      • setMaxXmitBufSize

        public void setMaxXmitBufSize​(int max_xmit_buf_size)

      • getMaxXmitSize

        public long getMaxXmitSize()
        Deprecated.
        removed in 2.6
        Returns:

      • setMaxXmitSize

        public void setMaxXmitSize​(long max_xmit_size)
        Deprecated.
        removed in 2.6
        Parameters:
        max_xmit_size -

      • isLogDiscardMsgs

        public boolean isLogDiscardMsgs()

      • setLogDiscardMsgs

        public void setLogDiscardMsgs​(boolean log_discard_msgs)

      • setProperties

        public boolean setProperties​(java.util.Properties props)
        Description copied from class: Protocol
        Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:
         "loopback=false;unicast_inport=4444"
        Overrides:
        setProperties in class Protocol

      • dumpStats

        public java.util.Map<java.lang.String,​java.lang.Object> dumpStats()
        Overrides:
        dumpStats in class Protocol

      • printStats

        public java.lang.String printStats()
        Overrides:
        printStats in class Protocol

      • printStabilityMessages

        public java.lang.String printStabilityMessages()

      • printStabilityHistory

        public java.lang.String printStabilityHistory()

      • printMergeHistory

        public java.lang.String printMergeHistory()

      • printLossRates

        public java.lang.String printLossRates()

      • getAverageLossRate

        public double getAverageLossRate()

      • getAverageSmoothedLossRate

        public double getAverageSmoothedLossRate()

      • providedUpServices

        public java.util.Vector<java.lang.Integer> providedUpServices()
        Description copied from class: Protocol
        List of events that are provided to layers above (they will be handled when sent down from above).
        Overrides:
        providedUpServices in class Protocol
        Returns:
        Vector (of Integers)

      • 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)
        Callback. Called by superclass when event may be handled.

        Do not use down_prot.down() in this method as the event is passed down by default by the superclass after this method returns !

        Overrides:
        down in class Protocol

      • up

        public java.lang.Object up​(Event evt)
        Callback. Called by superclass when event may be handled.

        Do not use PassUp in this method as the event is passed up by default by the superclass after this method returns !

        Overrides:
        up in class Protocol

      • getDigest

        public Digest getDigest()
        Returns a message digest: for each member P the lowest, highest delivered and highest received seqno is added

      • retransmit

        public void retransmit​(long first_seqno,
                       long last_seqno,
                       Address sender)
        Implementation of Retransmitter.RetransmitCommand. Called by retransmission thread when gap is detected.
        Specified by:
        retransmit in interface Retransmitter.RetransmitCommand
        Parameters:
        first_seqno - The sequence number of the first missing message
        last_seqno - The sequence number of the last missing message
        sender - The destination of the member to which the retransmit request will be sent (nak-based scheme), or to which the message will be retransmitted (ack-based scheme).

      • retransmit

        protected void retransmit​(long first_seqno,
                          long last_seqno,
                          Address sender,
                          boolean multicast_xmit_request)

      • printMessages

        public java.lang.String printMessages()

      • printRetransmissionAvgs

        public java.lang.String printRetransmissionAvgs()

      • printSmoothedRetransmissionAvgs

        public java.lang.String printSmoothedRetransmissionAvgs()

      • printRetransmissionTimes

        public java.lang.String printRetransmissionTimes()

      • getTotalAverageRetransmissionTime

        public double getTotalAverageRetransmissionTime()

      • getTotalAverageSmoothedRetransmissionTime

        public double getTotalAverageSmoothedRetransmissionTime()

      • getSmoothedAverageRetransmissionTime

        public double getSmoothedAverageRetransmissionTime​(Address sender)
        Returns the smoothed average retransmission time for a given sender