org.jgroups.protocols

Class RSVP

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.RSVP

public class RSVP
extends Protocol

Protocol which implements synchronous messages (https://issues.jboss.org/browse/JGRP-1389). A send of a message M with flag RSVP set will block until all non-faulty recipients (one for unicasts, N for multicasts) have acked M, or until a timeout kicks in.

Since:

3.1

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	RSVP.Entry
protected class	RSVP.ResendTask
protected static class	RSVP.RsvpHeader

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	ack_on_delivery
protected short	current_id ID to be used to identify messages.
protected boolean	handle_unicasts
protected java.util.concurrent.ConcurrentMap<java.lang.Short,RSVP.Entry>	ids Used to store IDs and their acks
protected Address	local_addr
protected java.util.List<Address>	members
protected long	resend_interval
protected java.util.concurrent.Future<?>	resend_task
protected boolean	throw_exception_on_timeout
protected long	timeout
protected TimeScheduler	timer

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
RSVP()

Method Summary

Modifier and Type	Method and Description
java.lang.Object	down(Event evt) An event is to be sent down the stack.
protected short	getNextId()
int	getPendingRsvpRequests()
protected void	handleResponse(Address member, short id)
protected void	handleView(View view)
void	init() Called after instance has been created (null constructor) and before protocol is started.
protected boolean	isResendTaskRunning()
protected void	sendResponse(Address dest, short id)
void	start() This method is called on a Channel.connect(String).
protected void	startResendTask()
void	stop() This method is called on a Channel.disconnect().
protected void	stopResendTask()
java.lang.Object	up(Event evt) An event was received from the layer below.
void	up(MessageBatch batch) Sends up a multiple messages in a MessageBatch.

Methods inherited from class org.jgroups.stack.Protocol

accept, afterCreationHook, destroy, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, resetStats, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled

Methods inherited from class java.lang.Object

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

Field Detail

timeout

protected long timeout

throw_exception_on_timeout

protected boolean throw_exception_on_timeout

ack_on_delivery

protected boolean ack_on_delivery

resend_interval

protected long resend_interval

current_id

protected short current_id

ID to be used to identify messages. Short.MAX_VALUE (ca 32K plus 32K negative) should be enough, and wrap-around shouldn't be an issue. Using Message.Flag.RSVP should be the exception, not the rule...

timer

protected TimeScheduler timer

members

protected volatile java.util.List<Address> members

local_addr

protected Address local_addr

ids

protected final java.util.concurrent.ConcurrentMap<java.lang.Short,RSVP.Entry> ids

Used to store IDs and their acks

resend_task

protected java.util.concurrent.Future<?> resend_task

handle_unicasts

protected boolean handle_unicasts

Constructor Detail

RSVP

public RSVP()

Method Detail

getPendingRsvpRequests

public int getPendingRsvpRequests()

init

public void init()
          throws java.lang.Exception

Description copied from class: Protocol

Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.

Overrides:

init in class Protocol

Throws:

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

start

public void start()
           throws java.lang.Exception

Description copied from class: Protocol

This method is called on a Channel.connect(String). Starts work. Protocols are connected and queues are ready to receive events. Will be called from bottom to top. This call will replace the START and START_OK events.

Overrides:

start in class Protocol

Throws:

java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception

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

down

public java.lang.Object 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 down_prot.down(). 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 up_prot.up().

Overrides:

down in class Protocol

up

public java.lang.Object 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 down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:

up in class Protocol

up

public void up(MessageBatch batch)

Description copied from class: Protocol

Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(org.jgroups.Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.getMatchingMessages(short,boolean)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

Overrides:

up in class Protocol

Parameters:

batch - The message batch

handleView

protected void handleView(View view)

handleResponse

protected void handleResponse(Address member,
                              short id)

sendResponse

protected void sendResponse(Address dest,
                            short id)

getNextId

protected short getNextId()

startResendTask

protected void startResendTask()

stopResendTask

protected void stopResendTask()

isResendTaskRunning

protected boolean isResendTaskRunning()