org.jgroups.protocols.pbcast
Class NAKACK

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

All Implemented Interfaces:

DiagnosticsHandler.ProbeHandler, Retransmitter.RetransmitCommand

public class NAKACK
extends Protocol
implements Retransmitter.RetransmitCommand, DiagnosticsHandler.ProbeHandler

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.

Author:

Bela Ban

Field Summary

protected BoundedList<Message>	become_server_queue
protected int	become_server_queue_size
protected BoundedList<java.lang.String>	digest_history Keeps a bounded list of the last N digest sets
protected int	num_messages_received
protected int	num_messages_sent
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
protected SuppressLog<Address>	suppress_log_non_member Log to suppress identical warnings for messages from non-members
protected long	suppress_time_non_member_warnings
protected long	xmit_stagger_timeout

Fields inherited from class org.jgroups.stack.Protocol

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

Constructor Summary

NAKACK()

Method Summary

protected void	checkForRebroadcasts()
void	clearNonMemberCache()
void	compact()
java.lang.Object	down(Event evt) Callback.
java.util.Map<java.lang.String,java.lang.Object>	dumpStats()
protected void	flushBecomeServerQueue() Flushes the queue.
long	getCurrentSeqno()
Digest	getDigest() Returns a message digest: for each member P the highest delivered and received seqno is added
Digest	getDigest(Address mbr)
boolean	getLogDiscardMessages()
int	getNonMemberMessages()
int	getPendingXmitRequests()
long	getSizeOfAllMessages()
long	getSizeOfAllMessagesInclHeaders()
NakReceiverWindow	getWindow(Address mbr) Please don't use this method; it is only provided for unit testing !
long	getXmitRequestsReceived()
long	getXmitRequestsSent()
long	getXmitResponsesReceived()
long	getXmitResponsesSent()
int	getXmitTableMissingMessages()
int	getXmitTableSize()
java.util.Map<java.lang.String,java.lang.String>	handleProbe(java.lang.String... keys) Handles a probe.
void	init() Called after instance has been created (null constructor) and before protocol is started.
boolean	isDiscardDeliveredMsgs()
boolean	isUseMcastXmit()
boolean	isXmitFromRandomMember()
java.lang.String	printDigestHistory()
java.lang.String	printLossRates()
java.lang.String	printMessages()
java.lang.String	printRetransmitStats()
java.lang.String	printRetransmitTableSizes()
java.lang.String	printStabilityHistory()
java.lang.String	printStabilityMessages()
java.lang.String	printStats()
java.util.List<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)
protected void	send(Event evt, Message msg) Adds the message to the sent_msgs table and then passes it down the stack.
void	setDiscardDeliveredMsgs(boolean discard_delivered_msgs)
void	setLogDiscardMessages(boolean flag)
void	setLogDiscardMsgs(boolean flag)
void	setTimer(TimeScheduler timer) Only used for unit tests, don't use !
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.String[]	supportedKeys() Returns a list of supported keys
java.lang.Object	up(Event evt) Callback.

Methods inherited from class org.jgroups.stack.Protocol

destroy, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, providedDownServices, 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

Field Detail

xmit_stagger_timeout

protected long xmit_stagger_timeout

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

become_server_queue_size

protected int become_server_queue_size

suppress_time_non_member_warnings

protected long suppress_time_non_member_warnings

num_messages_sent

protected int num_messages_sent

num_messages_received

protected int num_messages_received

stability_msgs

protected final BoundedList<Digest> stability_msgs

BoundedList, keeps the last 10 stability messages

digest_history

protected final BoundedList<java.lang.String> digest_history

Keeps a bounded list of the last N digest sets

become_server_queue

protected BoundedList<Message> become_server_queue

suppress_log_non_member

protected SuppressLog<Address> suppress_log_non_member

Log to suppress identical warnings for messages from non-members

Constructor Detail

NAKACK

public NAKACK()

Method Detail

getNonMemberMessages

public int getNonMemberMessages()

clearNonMemberCache

public void clearNonMemberCache()

getXmitRequestsReceived

public long getXmitRequestsReceived()

getXmitRequestsSent

public long getXmitRequestsSent()

getXmitResponsesReceived

public long getXmitResponsesReceived()

getXmitResponsesSent

public long getXmitResponsesSent()

getPendingXmitRequests

public int getPendingXmitRequests()

getXmitTableSize

public int getXmitTableSize()

getXmitTableMissingMessages

public int getXmitTableMissingMessages()

getSizeOfAllMessages

public long getSizeOfAllMessages()

getSizeOfAllMessagesInclHeaders

public long getSizeOfAllMessagesInclHeaders()

getCurrentSeqno

public long getCurrentSeqno()

printRetransmitStats

public java.lang.String printRetransmitStats()

getWindow

public NakReceiverWindow getWindow(Address mbr)

Please don't use this method; it is only provided for unit testing !

Parameters:

mbr -

Returns:

setTimer

public void setTimer(TimeScheduler timer)

Only used for unit tests, don't use !

Parameters:

timer -

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

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)

setLogDiscardMessages

public void setLogDiscardMessages(boolean flag)

setLogDiscardMsgs

public void setLogDiscardMsgs(boolean flag)

getLogDiscardMessages

public boolean getLogDiscardMessages()

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()

printDigestHistory

public java.lang.String printDigestHistory()

printLossRates

public java.lang.String printLossRates()

printRetransmitTableSizes

public java.lang.String printRetransmitTableSizes()

compact

public void compact()

providedUpServices

public java.util.List<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

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

send

protected void send(Event evt,
                    Message msg)

Adds the message to the sent_msgs table and then passes it down the stack. Change Bela Ban May 26 2002: we don't store a copy of the message, but a reference ! This saves us a lot of memory. However, this also means that a message should not be changed after storing it in the sent-table ! See protocols/DESIGN for details. Made seqno increment and adding to sent_msgs atomic, e.g. seqno won't get incremented if adding to sent_msgs fails e.g. due to an OOM (see http://jira.jboss.com/jira/browse/JGRP-179). bela Jan 13 2006

flushBecomeServerQueue

protected void flushBecomeServerQueue()

Flushes the queue. Done in a separate thread as we don't want to block the ClientGmsImpl.installView(org.jgroups.View,org.jgroups.util.Digest) method (called when a view is installed).

checkForRebroadcasts

protected void checkForRebroadcasts()

getDigest

public Digest getDigest()

Returns a message digest: for each member P the highest delivered and received seqno is added

getDigest

public Digest getDigest(Address mbr)

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()

handleProbe

public java.util.Map<java.lang.String,java.lang.String> handleProbe(java.lang.String... keys)

Description copied from interface: DiagnosticsHandler.ProbeHandler

Handles a probe. For each key that is handled, the key and its result should be in the returned map.

Specified by:

handleProbe in interface DiagnosticsHandler.ProbeHandler

Returns:

Map. A map of keys and values. A null return value is permissible.

supportedKeys

public java.lang.String[] supportedKeys()

Description copied from interface: DiagnosticsHandler.ProbeHandler

Returns a list of supported keys

Specified by:

supportedKeys in interface DiagnosticsHandler.ProbeHandler