org.jgroups.protocols.pbcast
Class NAKACK

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.pbcast.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 Summary

protected BoundedList<java.lang.String>	merge_history
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
protected BoundedList<Digest>	stability_msgs BoundedList, keeps the last 10 stability messages

Fields inherited from class org.jgroups.stack.Protocol

down_prot, log, props, stack, stats, up_prot

Constructor Summary

NAKACK()

Method Summary

java.lang.Object	down(Event evt) Callback.
java.util.Map<java.lang.String,java.lang.Object>	dumpStats()
double	getAverageLossRate()
double	getAverageSmoothedLossRate()
Digest	getDigest() Returns a message digest: for each member P the lowest, highest delivered and highest received seqno is added
int	getGcLag()
int	getMaxXmitBufSize()
long	getMaxXmitSize() Deprecated. removed in 2.6
long	getMissingMessagesReceived()
java.lang.String	getName()
int	getPendingRetransmissionRequests()
int	getReceivedTableSize()
double	getSmoothedAverageRetransmissionTime(Address sender) Returns the smoothed average retransmission time for a given sender
double	getTotalAverageRetransmissionTime()
double	getTotalAverageSmoothedRetransmissionTime()
long	getXmitRequestsReceived()
long	getXmitRequestsSent()
long	getXmitResponsesReceived()
long	getXmitResponsesSent()
int	getXmitTableSize()
void	init() Called after instance has been created (null constructor) and before protocol is started.
boolean	isDiscardDeliveredMsgs()
boolean	isLogDiscardMsgs()
boolean	isUseMcastXmit()
boolean	isXmitFromRandomMember()
void	messageGapDetected(long from, long to, Address src) Called when a message gap is detected
void	missingMessageReceived(long seqno, Address original_sender)
java.lang.String	printLossRates()
java.lang.String	printMergeHistory()
java.lang.String	printMessages()
java.lang.String	printRetransmissionAvgs()
java.lang.String	printRetransmissionTimes()
java.lang.String	printSmoothedRetransmissionAvgs()
java.lang.String	printStabilityHistory()
java.lang.String	printStabilityMessages()
java.lang.String	printStats()
java.util.Vector<java.lang.Integer>	providedUpServices() List of events that are provided to layers above (they will be handled when sent down from above).
void	resetStats()
void	retransmit(long first_seqno, long last_seqno, Address sender) Implementation of Retransmitter.RetransmitCommand.
protected void	retransmit(long first_seqno, long last_seqno, Address sender, boolean multicast_xmit_request)
void	setDiscardDeliveredMsgs(boolean discard_delivered_msgs)
void	setGcLag(int gc_lag)
void	setLogDiscardMsgs(boolean log_discard_msgs)
void	setMaxXmitBufSize(int max_xmit_buf_size)
void	setMaxXmitSize(long max_xmit_size) Deprecated. removed in 2.6
boolean	setProperties(java.util.Properties props) Configures the protocol initially.
void	setUseMcastXmit(boolean use_mcast_xmit)
void	setXmitFromRandomMember(boolean xmit_from_random_member)
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) Callback.

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, providedDownServices, requiredDownServices, requiredUpServices, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, statsEnabled, upThreadEnabled

Methods inherited from class java.lang.Object

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

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()

resetStats

public void resetStats()

Overrides:

resetStats in class Protocol

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)

missingMessageReceived

public void missingMessageReceived(long seqno,
                                   Address original_sender)

Specified by:

missingMessageReceived in interface NakReceiverWindow.Listener

messageGapDetected

public void messageGapDetected(long from,
                               long to,
                               Address src)

Called when a message gap is detected

Specified by:

messageGapDetected in interface NakReceiverWindow.Listener

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