Package org.jgroups.protocols

Class DAISYCHAIN

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.DAISYCHAIN

All Implemented Interfaces:

Lifecycle

public class DAISYCHAIN
extends Protocol

Implementation of daisy chaining. Multicast messages are sent to our neighbor, which sends them to its neighbor etc. A TTL restricts the number of times a message is forwarded. The advantage of daisy chaining is that - for point-to-point transports such as TCP - we can avoid the N-1 issue: when A sends a multicast message to 10 members, it needs to send it 9 times. With daisy chaining, it sends it 1 time, and in the next round, can already send another message. This leads to much better throughput, see the ref in the JIRA.

Should be inserted just above MERGE3, in TCP based configurations. JIRA: https://issues.redhat.com/browse/JGRP-1021

Since:

2.11

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DAISYCHAIN.DaisyHeader

Field Summary

Fields

Modifier and Type	Field	Description
(package private) boolean	loopback
protected int	msgs_forwarded
protected int	msgs_sent
protected Address	next
protected TP	transport
protected View	view

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, local_addr, log, policies, stack, stats, up_prot

Constructor Summary

Constructors

Constructor	Description
DAISYCHAIN()

Method Summary

Modifier and Type	Method	Description
Object	down(Event evt)	An event is to be sent down the stack.
Object	down(Message msg)	A message is sent down the stack.
protected void	handleView(View view)
void	init()	Called after a protocol has been created and before the protocol is started.
void	resetStats()
Object	up(Message msg)	A single message was received.

Methods inherited from class org.jgroups.stack.Protocol

accept, addPolicy, addr, addr, afterCreationHook, destroy, down, enableStats, getAddress, getComponents, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getPolicies, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, policies, providedDownServices, providedUpServices, removePolicy, requiredDownServices, requiredUpServices, resetStatistics, setAddress, setDownProtocol, setErgonomics, setId, setLevel, setPolicies, setProtocolStack, setSocketFactory, setUpProtocol, setValue, start, statsEnabled, stop, toString, up, up

Methods inherited from class java.lang.Object

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

Field Details

loopback

boolean loopback

next

protected volatile Address next

view

protected volatile View view

msgs_forwarded

protected int msgs_forwarded

msgs_sent

protected int msgs_sent

transport

protected TP transport

Constructor Details

DAISYCHAIN

public DAISYCHAIN()

Method Details

resetStats

public void resetStats()

Overrides:

resetStats in class Protocol

init

public void init()
          throws Exception

Description copied from class: Protocol

Called after a protocol has been created and before the protocol is started. Attributes are already set. Other protocols are not yet connected and events cannot yet be sent.

Specified by:

init in interface Lifecycle

Overrides:

init in class Protocol

Throws:

Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the the channel constructor will throw an exception

down

public Object down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. A protocol 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 protocol may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down().

Overrides:

down in class Protocol

down

public Object down(Message msg)

Description copied from class: Protocol

A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it, before passing it down.

Overrides:

down in class Protocol

up

public Object up(Message msg)

Description copied from class: Protocol

A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.

Overrides:

up in class Protocol

handleView

protected void handleView(View view)