org.jgroups.protocols
Class VIEW_SYNC

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.VIEW_SYNC

public class VIEW_SYNC
extends Protocol

Periodically sends the view to the group. When a view is received which is greater than the current view, we install it. Otherwise we simply discard it. This is used to solve the problem for unreliable view dissemination outlined in JGroups/doc/ReliableViewInstallation.txt. This protocol is supposed to be just below GMS.

Author:

Bela Ban

Nested Class Summary

static class

VIEW_SYNC.ViewSyncHeader

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

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

Constructor Summary

VIEW_SYNC()

Method Summary

java.lang.Object	down(Event evt) An event is to be sent down the stack.
long	getAverageSendInterval()
int	getNumViewsAdjusted()
int	getNumViewsSent()
void	resetStats()
void	sendViewRequest() Sends a VIEW_SYNC_REQ to all members, every member replies with a VIEW multicast
void	setAverageSendInterval(long gossip_interval)
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) An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getId, getLevel, getName, getProperties, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getValue, init, isErgonomics, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, setDownProtocol, setErgonomics, setId, setLevel, setProperties, setPropertiesInternal, setProperty, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled, upThreadEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

VIEW_SYNC

public VIEW_SYNC()

Method Detail

getAverageSendInterval

public long getAverageSendInterval()

setAverageSendInterval

public void setAverageSendInterval(long gossip_interval)

getNumViewsSent

public int getNumViewsSent()

getNumViewsAdjusted

public int getNumViewsAdjusted()

resetStats

public void resetStats()

Overrides:

resetStats 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

sendViewRequest

public void sendViewRequest()

Sends a VIEW_SYNC_REQ to all members, every member replies with a VIEW multicast

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