org.jgroups.protocols
Class SMACK

java.lang.Object
  extended byorg.jgroups.stack.Protocol
      extended byorg.jgroups.protocols.SMACK
All Implemented Interfaces:
AckMcastSenderWindow.RetransmitCommand

public class SMACK
extends Protocol
implements AckMcastSenderWindow.RetransmitCommand

Simple Multicast ACK protocol. A positive acknowledgment-based protocol for reliable delivery of multicast messages, which does not need any group membership service. Basically works as follows:

Advantage of this protocol: no group membership necessary, fast.

Version:
$Revision: 1.12 $
Author:
Bela Ban Aug 2002
To do:
Initial mcast to announce new member (for view change).
Fix membershop bug: start a, b, kill b, restart b: b will be suspected by a.

Nested Class Summary
static class SMACK.SmackHeader
           
 
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
 
Constructor Summary
SMACK()
           
 
Method Summary
 void down(Event evt)
          An event is to be sent down the stack.
 java.lang.String getName()
           
 void retransmit(long seqno, Message msg, Address dest)
          Retranmit the given msg
 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, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, start, startDownHandler, startUpHandler, statsEnabled, stopInternal, upThreadEnabled
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SMACK

public SMACK()
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

retransmit

public void retransmit(long seqno,
                       Message msg,
                       Address dest)
Description copied from interface: AckMcastSenderWindow.RetransmitCommand
Retranmit the given msg

Specified by:
retransmit in interface AckMcastSenderWindow.RetransmitCommand
Parameters:
seqno - the sequence number associated with the message
msg - the msg to retransmit (it should be a copy!)
dest - the msg destination


Copyright ? 1998-2005 Bela Ban. All Rights Reserved.