org.jgroups.protocols.pbcast
Class FD

java.lang.Object
  extended byorg.jgroups.stack.Protocol
      extended byorg.jgroups.protocols.pbcast.FD
All Implemented Interfaces:
java.lang.Runnable

public class FD
extends Protocol
implements java.lang.Runnable

Passive failure detection protocol. It assumes a pbcast protocol, which uses rounds of gossiping for reliable message delivery. Gossip protocols typically involve all the members sending gossips in regular intervals. This protocol therefore works as follows: it allocates a timestamp for each member and updates the timestamp whenever it receives a message from a sender P. Any type of message is accepted from P. For example, PBCAST regularly sends the following messages:

Author:
Bela Ban

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, up_handler, up_prot, up_queue, up_thread, up_thread_prio
 
Constructor Summary
FD()
           
 
Method Summary
 void down(Event evt)
          An event is to be sent down the stack.
 java.lang.String getName()
           
 void run()
           
 boolean setProperties(java.util.Properties props)
          Configures the protocol initially.
 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, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, passDown, passUp, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setUpProtocol, start, startDownHandler, startUpHandler, stopInternal
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FD

public FD()
Method Detail

getName

public java.lang.String getName()
Specified by:
getName in class Protocol

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

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

up

public void 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 passDown() or c) the event (or another event) is sent up the stack using passUp().

Overrides:
up in class Protocol

down

public void 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 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 class Protocol

run

public void run()
Specified by:
run in interface java.lang.Runnable


Copyright ? 2001,2002 www.jgroups.com . All Rights Reserved.