org.jgroups.stack
Class AckSenderWindow

java.lang.Object
  org.jgroups.stack.AckSenderWindow

All Implemented Interfaces:

Retransmitter.RetransmitCommand

public class AckSenderWindow
extends java.lang.Object
implements Retransmitter.RetransmitCommand

ACK-based sliding window for a sender. Messages are added to the window keyed by seqno When an ACK is received, the corresponding message is removed. The Retransmitter continously iterates over the entries in the hashmap, retransmitting messages based on their creation time and an (increasing) timeout. When there are no more messages in the retransmission table left, the thread terminates. It will be re-activated when a new entry is added to the retransmission table.

Author:

Bela Ban

Nested Class Summary

static interface

AckSenderWindow.RetransmitCommand

Constructor Summary

AckSenderWindow()
Creates an instance without retransmitter

AckSenderWindow(AckSenderWindow.RetransmitCommand com)

AckSenderWindow(AckSenderWindow.RetransmitCommand com, Interval interval, TimeScheduler sched)

AckSenderWindow(AckSenderWindow.RetransmitCommand com, Interval interval, TimeScheduler sched, Address sender)

Method Summary

void	ack(long seqno) Removes all messages less than or equal to seqno from msgs, and cancels their retransmission
void	add(long seqno, Message msg) Adds a new message to the retransmission table.
void	addToMessages(long seqno, Message msg)
void	addToRetransmitter(long seqno, Message msg)
Message	get(long seqno)
long	getHighest()
long	getLowest() Only to be used for testing purposes
Message	getLowestMessage() Returns the message with the lowest seqno
java.lang.String	printDetails()
void	reset()
void	retransmit(long first_seqno, long last_seqno, Address sender) Get the missing messages between sequence numbers first_seqno and last_seqno.
int	size()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

AckSenderWindow

public AckSenderWindow(AckSenderWindow.RetransmitCommand com)

AckSenderWindow

public AckSenderWindow(AckSenderWindow.RetransmitCommand com,
                       Interval interval,
                       TimeScheduler sched)

AckSenderWindow

public AckSenderWindow(AckSenderWindow.RetransmitCommand com,
                       Interval interval,
                       TimeScheduler sched,
                       Address sender)

AckSenderWindow

public AckSenderWindow()

Creates an instance without retransmitter

Method Detail

getLowest

public long getLowest()

Only to be used for testing purposes

getHighest

public long getHighest()

reset

public void reset()

get

public Message get(long seqno)

add

public void add(long seqno,
                Message msg)

Adds a new message to the retransmission table. The message will be retransmitted (based on timeouts passed into AckSenderWindow until (1) an ACK is received or (2) the AckSenderWindow is stopped (@link{#reset})

addToMessages

public void addToMessages(long seqno,
                          Message msg)

addToRetransmitter

public void addToRetransmitter(long seqno,
                               Message msg)

ack

public void ack(long seqno)

Removes all messages less than or equal to seqno from msgs, and cancels their retransmission

getLowestMessage

public Message getLowestMessage()

Returns the message with the lowest seqno

size

public int size()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

printDetails

public java.lang.String printDetails()

retransmit

public void retransmit(long first_seqno,
                       long last_seqno,
                       Address sender)

Description copied from interface: Retransmitter.RetransmitCommand

Get the missing messages between sequence numbers first_seqno and last_seqno. This can either be done by sending a retransmit message to destination sender (nak-based scheme), or by retransmitting the missing message(s) to sender (ack-based scheme).

Specified by:

retransmit in interface Retransmitter.RetransmitCommand

Parameters:

first_seqno - The sequence number of the first missing message

last_seqno - The sequence number of the last missing message

sender - The destination of the member to which the retransmit request will be sent (nak-based scheme), or to which the message will be retransmitted (ack-based scheme).