Package org.jgroups.stack

Class Retransmitter

java.lang.Object

org.jgroups.stack.Retransmitter

Direct Known Subclasses:

DefaultRetransmitter, RangeBasedRetransmitter

public abstract class Retransmitter
extends Object

Abstract class of a retransmitter. Maintains a pool of sequence numbers of messages that need to be retransmitted. Messages are aged and retransmission requests sent according to age (configurable backoff). If a TimeScheduler instance is given to the constructor, it will be used, otherwise Reransmitter will create its own. The retransmit timeouts have to be set first thing after creating an instance. The add() method adds the sequence numbers of messages to be retransmitted. The remove() method removes a sequence number again, cancelling retransmission requests for it. Whenever a message needs to be retransmitted, the RetransmitCommand.retransmit() method is called. It can be used e.g. by an ack-based scheme (e.g. AckSenderWindow) to retransmit a message to the receiver, or by a nak-based scheme to send a retransmission request to the sender of the missing message.

Version:

$Revision: 1.33 $

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Retransmitter.RetransmitCommand	Retransmit command (see Gamma et al.) used to retrieve missing messages
protected class	Retransmitter.Task

Field Summary

Fields

Modifier and Type	Field	Description
protected final Retransmitter.RetransmitCommand	cmd
protected static final Log	log
protected Interval	RETRANSMIT_TIMEOUTS	Default retransmit intervals (ms) - exponential approx.
protected final Address	sender
protected final TimeScheduler	timer

Constructor Summary

Constructors

Constructor	Description
Retransmitter(Address sender, Retransmitter.RetransmitCommand cmd, TimeScheduler sched)	Create a new Retransmitter associated with the given sender address

Method Summary

Modifier and Type	Method	Description
abstract void	add(long first_seqno, long last_seqno)	Add messages from first_seqno to last_seqnoinvalid input: '<'/code/> for retransmission
abstract int	remove(long seqno)	Remove the given sequence number from retransmission
abstract void	reset()	Reset the retransmitter: clear all msgs and cancel all the respective tasks
void	setRetransmitTimeouts(Interval interval)
abstract int	size()

Methods inherited from class java.lang.Object

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

Field Details

RETRANSMIT_TIMEOUTS

protected Interval RETRANSMIT_TIMEOUTS

Default retransmit intervals (ms) - exponential approx.

sender

protected final Address sender

cmd

protected final Retransmitter.RetransmitCommand cmd

timer

protected final TimeScheduler timer

log

protected static final Log log

Constructor Details

Retransmitter

public Retransmitter(Address sender,
 Retransmitter.RetransmitCommand cmd,
 TimeScheduler sched)

Create a new Retransmitter associated with the given sender address

Parameters:

sender - the address from which retransmissions are expected or to which retransmissions are sent

cmd - the retransmission callback reference

sched - retransmissions scheduler

Method Details

setRetransmitTimeouts

public void setRetransmitTimeouts(Interval interval)

add

public abstract void add(long first_seqno,
 long last_seqno)

Add messages from first_seqno to last_seqnoinvalid input: '<'/code/> for retransmission

remove

public abstract int remove(long seqno)

Remove the given sequence number from retransmission

reset

public abstract void reset()

Reset the retransmitter: clear all msgs and cancel all the respective tasks

size

public abstract int size()