AckSenderWindow (JGroups)

Class AckSenderWindow

public class AckSenderWindow extends 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
interface	AckSenderWindow.RetransmitCommand

Nested Class Summary

interface

AckSenderWindow.RetransmitCommand

Constructor Summary
	AckSenderWindow(AckSenderWindow.RetransmitCommand com) Creates a new instance.
	AckSenderWindow(AckSenderWindow.RetransmitCommand com, long[] interval)
	AckSenderWindow(AckSenderWindow.RetransmitCommand com, long[] interval, TimeScheduler sched)

Constructor Summary

AckSenderWindow(AckSenderWindow.RetransmitCommand com)

Creates a new instance.

AckSenderWindow(AckSenderWindow.RetransmitCommand com, long[] interval)

AckSenderWindow(AckSenderWindow.RetransmitCommand com, long[] interval, TimeScheduler sched)

Method Summary
void	ack(long seqno) Removes the message from `msgs`, removing them also from retransmission.
void	add(long seqno, Message msg) Adds a new message to the retransmission table.
static void	main(String[] args)
String	printDetails()
void	reset()
void	retransmit(long first_seqno, long last_seqno, Address sender)
int	size()
String	toString()

Method Summary

void

ack(long seqno)

Removes the message from msgs, removing them also from retransmission.

void

add(long seqno, Message msg)

Adds a new message to the retransmission table.

static void

main(String[] args)

String

printDetails()

void

reset()

void

retransmit(long first_seqno, long last_seqno, Address sender)

int

size()

String

toString()

Constructor Detail

AckSenderWindow

Creates a new instance. Thre retransmission thread has to be started separately with start().

Parameters: com If not null, its method retransmit() will be called when a message needs to be retransmitted (called by the Retransmitter).

AckSenderWindow

Method Detail

ack

Removes the message from msgs, removing them also from retransmission. If sliding window protocol is used, and was queueing, check whether we can resume adding elements. Add all elements. If this goes above window_size, stop adding and back to queueing. Else set queueing to false.

add

Adds a new message to the retransmission table. If the message won't have received an ack within a certain time frame, the retransmission thread will retransmit the message to the receiver. If a sliding window protocol is used, we only add up to window_size messages. If the table is full, we add all new messages to a queue. Those will only be added once the table drains below a certain threshold (min_threshold)