org.jgroups
Class ReceiverAdapter

java.lang.Object
  org.jgroups.ReceiverAdapter

All Implemented Interfaces:

MembershipListener, MessageListener, Receiver

Direct Known Subclasses:

Chat, Draw, QuoteServer, RELAY.Receiver, RelayDemoRpc, Relayer.Bridge, ReplicatedTree, ViewDemo

public class ReceiverAdapter
extends java.lang.Object
implements Receiver

An adapter implementing the Receiver interface with no-op implementations. When implementing a callback, we can simply extend ReceiverAdapter and overwrite receive() in order to not having to implement all callbacks of the interface.

Since:

2.0

Author:

Bela Ban

Constructor Summary

ReceiverAdapter()

Method Summary

void	block() Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages.
void	getState(java.io.OutputStream output) Allows an application to write a state through a provided OutputStream.
void	receive(Message msg) Called when a message is received.
void	setState(java.io.InputStream input) Allows an application to read a state through a provided InputStream.
void	suspect(Address mbr) Called whenever a member is suspected of having crashed, but has not yet been excluded.
void	unblock() Called after the FLUSH protocol has unblocked previously blocked senders, and messages can be sent again.
void	viewAccepted(View view) Called when a change in membership has occurred.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReceiverAdapter

public ReceiverAdapter()

Method Detail

receive

public void receive(Message msg)

Called when a message is received.

Specified by:

receive in interface MessageListener

getState

public void getState(java.io.OutputStream output)
              throws java.lang.Exception

Allows an application to write a state through a provided OutputStream. After the state has been written the OutputStream doesn't need to be closed as stream closing is automatically done when a calling thread returns from this callback.

Specified by:

getState in interface MessageListener

Parameters:

output - the OutputStream

Throws:

java.lang.Exception - if the streaming fails, any exceptions should be thrown so that the state requester can re-throw them and let the caller know what happened

See Also:

OutputStream.close()

setState

public void setState(java.io.InputStream input)
              throws java.lang.Exception

Allows an application to read a state through a provided InputStream. After the state has been read the InputStream doesn't need to be closed as stream closing is automatically done when a calling thread returns from this callback.

Specified by:

setState in interface MessageListener

Parameters:

input - the InputStream

Throws:

java.lang.Exception - if the streaming fails, any exceptions should be thrown so that the state requester can catch them and thus know what happened

See Also:

InputStream.close()

viewAccepted

public void viewAccepted(View view)

Called when a change in membership has occurred. No long running actions, sending of messages or anything that could block should be done in this callback. If some long running action needs to be performed, it should be done in a separate thread.

Note that on reception of the first view (a new member just joined), the channel will not yet be in the connected state. This only happens when Channel.connect(String) returns.

Specified by:

viewAccepted in interface MembershipListener

suspect

public void suspect(Address mbr)

Called whenever a member is suspected of having crashed, but has not yet been excluded.

Specified by:

suspect in interface MembershipListener

block

public void block()

Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages. Any messages sent after returning from this callback might get blocked by the FLUSH protocol. When the FLUSH protocol is done, and messages can be sent again, the FLUSH protocol will simply unblock all pending messages. If a callback for unblocking is desired, implement MembershipListener.unblock(). Note that block() is the equivalent of reception of a BlockEvent in the pull mode.

Specified by:

block in interface MembershipListener

unblock

public void unblock()

Called after the FLUSH protocol has unblocked previously blocked senders, and messages can be sent again. This callback only needs to be implemented if we require a notification of that.

Note that during new view installation we provide guarantee that unblock invocation strictly follows view installation at some node A belonging to that view . However, some other message M may squeeze in between view and unblock callbacks. For more details see https://jira.jboss.org/jira/browse/JGRP-986

Specified by:

unblock in interface MembershipListener