org.jgroups.protocols

Class 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.
Version:
$Id: VIEW_SYNC.java,v 1.5 2005/12/16 16:18:16 belaban Exp $
Author:
Bela Ban

Nested Class Summary

static class
VIEW_SYNC.ViewSyncHeader

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, trace, up_handler, up_prot, up_queue, up_thread, up_thread_prio, warn

Method Summary

void
down(Event evt)
An event is to be sent down the stack.
long
getAverageSendInterval()
String
getName()
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)
boolean
setProperties(Properties props)
Configures the protocol initially.
void
start()
This method is called on a Channel.connect(String).
void
stop()
This method is called on a Channel.disconnect().
void
up(Event evt)
An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

destroy, down, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getName, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setObserver, setProperties, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, start, startDownHandler, startUpHandler, statsEnabled, stop, stopInternal, up, upThreadEnabled

Method Details

down

public void down(Event evt)
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 passDown(). 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 passUp().
Overrides:
down in interface Protocol

getAverageSendInterval

public long getAverageSendInterval()

getName

public String getName()
Overrides:
getName in interface Protocol

getNumViewsAdjusted

public int getNumViewsAdjusted()

getNumViewsSent

public int getNumViewsSent()

resetStats

public void resetStats()
Overrides:
resetStats in interface Protocol

sendViewRequest

public void sendViewRequest()
Sends a VIEW_SYNC_REQ to all members, every member replies with a VIEW multicast

setAverageSendInterval

public void setAverageSendInterval(long gossip_interval)

setProperties

public boolean setProperties(Properties props)
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 interface Protocol

start

public void start()
            throws Exception
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 interface Protocol

stop

public void stop()
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 interface Protocol

up

public void up(Event evt)
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 passDown() or c) the event (or another event) is sent up the stack using passUp().
Overrides:
up in interface Protocol

Copyright B) 1998-2005 Bela Ban. All Rights Reserved.