org.jgroups.protocols.pbcast
Class GMS

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

All Implemented Interfaces:

DiagnosticsHandler.ProbeHandler

public class GMS
extends Protocol
implements DiagnosticsHandler.ProbeHandler

Group membership protocol. Handles joins/leaves/crashes (suspicions) and emits new views accordingly. Use VIEW_ENFORCER on top of this layer to make sure new members don't receive any messages until they are members

Author:

Bela Ban

Nested Class Summary

static class

GMS.GmsHeader

Field Summary

protected AckCollector	ack_collector To collect VIEW_ACKs from all members
protected java.lang.Class<java.util.concurrent.Callable<java.lang.Boolean>>	flushInvokerClass
protected Address	local_addr
protected long	ltime
protected Membership	members
protected AckCollector	merge_ack_collector
protected int	num_prev_mbrs
protected TimeScheduler	timer
protected View	view

Fields inherited from class org.jgroups.stack.Protocol

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

Constructor Summary

GMS()

Method Summary

MergeId	_getMergeId()
protected boolean	_startFlush(View new_view, int maxAttempts, boolean resumeIfFailed, long randomFloor, long randomCeiling)
void	becomeClient()
void	becomeCoordinator()
void	becomeParticipant()
void	cancelMerge()
void	castViewChange(View new_view, Digest digest, JoinRsp jr, java.util.Collection<Address> newMembers) Broadcasts the new view and digest, and waits for acks from all members in the list given as argument.
protected Address	determineCoordinator()
java.lang.Object	down(Event evt) An event is to be sent down the stack.
java.lang.String	dumpViewHandlerHistory()
java.lang.String	dumpViewHandlerQueue()
void	fixDigests()
Digest	getDigest() Sends down a GET_DIGEST event and waits for the GET_DIGEST_OK response, or timeout, whichever occurs first
GmsImpl	getImpl()
long	getJoinTimeout()
java.lang.String	getLocalAddress()
boolean	getLogCollectMessages()
long	getMaxBundlingTime()
long	getMaxJoinAttempts()
java.lang.String	getMembers()
java.lang.String	getMergeId()
Merger	getMerger() Only used for internal testing, don't use this method !
long	getMergeTimeout()
View	getNextView(java.util.Collection<Address> new_mbrs, java.util.Collection<Address> old_mbrs, java.util.Collection<Address> suspected_mbrs) Computes the next view.
int	getNumberOfViews()
int	getNumMembers()
java.lang.String	getView()
long	getViewAckCollectionTimeout()
Tuple<View,Digest>	getViewAndDigest() Returns the current view and digest
int	getViewHandlerSize()
ViewId	getViewId()
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.
void	installView(View new_view)
void	installView(View new_view, Digest digest) Sets the new view and sends a VIEW_CHANGE event up and down the stack.
boolean	isCoordinator()
boolean	isMergeInProgress()
boolean	isMergeKillerRunning()
boolean	isMergeTaskRunning()
boolean	isViewBundling()
boolean	isViewHandlerSuspended()
void	mergeDigest(Digest d) Send down a MERGE_DIGEST event
java.lang.String	printMergeIdHistory()
java.lang.String	printPreviousMembers()
java.lang.String	printPreviousViews()
java.util.List<java.lang.Integer>	providedDownServices() List of events that are provided to layers below (they will be handled when sent down below)
java.util.List<java.lang.Integer>	requiredDownServices() List of events that are required to be answered by some layer below
void	resetStats()
void	resumeViewHandler()
void	sendJoinResponse(JoinRsp rsp, Address dest)
void	setDigest(Digest d) Send down a SET_DIGEST event
void	setImpl(GmsImpl new_impl)
void	setJoinTimeout(long t)
void	setLogCollectMessages(boolean flag)
void	setMaxBundlingTime(long max_bundling_time)
void	setMaxJoinAttempts(long t)
void	setMergeTimeout(long timeout)
void	setPrintLocalAddr(boolean flag)
void	setPrintLocalAddress(boolean flag)
void	setViewAckCollectionTimeout(long view_ack_collection_timeout)
void	setViewBundling(boolean view_bundling)
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
void	suspect(java.lang.String suspected_member)
void	suspendViewHandler()
java.lang.Object	up(Event evt) An event was received from the layer below.
protected boolean	wouldBeNewCoordinator(Address potential_new_coord) Checks whether the potential_new_coord would be the new coordinator (2nd in line)

Methods inherited from class org.jgroups.stack.Protocol

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

num_prev_mbrs

protected int num_prev_mbrs

flushInvokerClass

protected java.lang.Class<java.util.concurrent.Callable<java.lang.Boolean>> flushInvokerClass

local_addr

protected Address local_addr

members

protected final Membership members

view

protected View view

ltime

protected long ltime

timer

protected TimeScheduler timer

ack_collector

protected final AckCollector ack_collector

To collect VIEW_ACKs from all members

merge_ack_collector

protected final AckCollector merge_ack_collector

Constructor Detail

GMS

public GMS()

Method Detail

getViewId

public ViewId getViewId()

getViewAndDigest

public Tuple<View,Digest> getViewAndDigest()

Returns the current view and digest

getView

public java.lang.String getView()

getNumberOfViews

public int getNumberOfViews()

getLocalAddress

public java.lang.String getLocalAddress()

getMembers

public java.lang.String getMembers()

getNumMembers

public int getNumMembers()

getJoinTimeout

public long getJoinTimeout()

setJoinTimeout

public void setJoinTimeout(long t)

getMergeTimeout

public long getMergeTimeout()

setMergeTimeout

public void setMergeTimeout(long timeout)

getMaxJoinAttempts

public long getMaxJoinAttempts()

setMaxJoinAttempts

public void setMaxJoinAttempts(long t)

getMergeId

public java.lang.String getMergeId()

isMergeInProgress

public boolean isMergeInProgress()

getMerger

public Merger getMerger()

Only used for internal testing, don't use this method !

printMergeIdHistory

public java.lang.String printMergeIdHistory()

printPreviousMembers

public java.lang.String printPreviousMembers()

setPrintLocalAddress

public void setPrintLocalAddress(boolean flag)

setPrintLocalAddr

public void setPrintLocalAddr(boolean flag)

getViewAckCollectionTimeout

public long getViewAckCollectionTimeout()

setViewAckCollectionTimeout

public void setViewAckCollectionTimeout(long view_ack_collection_timeout)

isViewBundling

public boolean isViewBundling()

setViewBundling

public void setViewBundling(boolean view_bundling)

getMaxBundlingTime

public long getMaxBundlingTime()

setMaxBundlingTime

public void setMaxBundlingTime(long max_bundling_time)

getViewHandlerSize

public int getViewHandlerSize()

isViewHandlerSuspended

public boolean isViewHandlerSuspended()

dumpViewHandlerQueue

public java.lang.String dumpViewHandlerQueue()

dumpViewHandlerHistory

public java.lang.String dumpViewHandlerHistory()

suspendViewHandler

public void suspendViewHandler()

resumeViewHandler

public void resumeViewHandler()

printPreviousViews

public java.lang.String printPreviousViews()

suspect

public void suspect(java.lang.String suspected_member)

isCoordinator

public boolean isCoordinator()

_getMergeId

public MergeId _getMergeId()

setLogCollectMessages

public void setLogCollectMessages(boolean flag)

getLogCollectMessages

public boolean getLogCollectMessages()

resetStats

public void resetStats()

Overrides:

resetStats in class Protocol

requiredDownServices

public java.util.List<java.lang.Integer> requiredDownServices()

Description copied from class: Protocol

List of events that are required to be answered by some layer below

Overrides:

requiredDownServices in class Protocol

providedDownServices

public java.util.List<java.lang.Integer> providedDownServices()

Description copied from class: Protocol

List of events that are provided to layers below (they will be handled when sent down below)

Overrides:

providedDownServices in class Protocol

setImpl

public void setImpl(GmsImpl new_impl)

getImpl

public GmsImpl getImpl()

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

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

becomeCoordinator

public void becomeCoordinator()

becomeParticipant

public void becomeParticipant()

becomeClient

public void becomeClient()

fixDigests

public void fixDigests()

cancelMerge

public void cancelMerge()

isMergeTaskRunning

public boolean isMergeTaskRunning()

isMergeKillerRunning

public boolean isMergeKillerRunning()

getNextView

public View getNextView(java.util.Collection<Address> new_mbrs,
                        java.util.Collection<Address> old_mbrs,
                        java.util.Collection<Address> suspected_mbrs)

Computes the next view. Returns a copy that has old_mbrs and suspected_mbrs removed and new_mbrs added.

castViewChange

public void castViewChange(View new_view,
                           Digest digest,
                           JoinRsp jr,
                           java.util.Collection<Address> newMembers)

Broadcasts the new view and digest, and waits for acks from all members in the list given as argument. If the list is null, we take the members who are part of new_view

sendJoinResponse

public void sendJoinResponse(JoinRsp rsp,
                             Address dest)

installView

public void installView(View new_view)

installView

public void installView(View new_view,
                        Digest digest)

Sets the new view and sends a VIEW_CHANGE event up and down the stack. If the view is a MergeView (subclass of View), then digest will be non-null and has to be set before installing the view.

determineCoordinator

protected Address determineCoordinator()

wouldBeNewCoordinator

protected boolean wouldBeNewCoordinator(Address potential_new_coord)

Checks whether the potential_new_coord would be the new coordinator (2nd in line)

setDigest

public void setDigest(Digest d)

Send down a SET_DIGEST event

mergeDigest

public void mergeDigest(Digest d)

Send down a MERGE_DIGEST event

getDigest

public Digest getDigest()

Sends down a GET_DIGEST event and waits for the GET_DIGEST_OK response, or timeout, whichever occurs first

_startFlush

protected boolean _startFlush(View new_view,
                              int maxAttempts,
                              boolean resumeIfFailed,
                              long randomFloor,
                              long randomCeiling)

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

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

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