org.jgroups.demos

Class QuoteServer

java.lang.Object

org.jgroups.demos.QuoteServer

All Implemented Interfaces:

MembershipListener, MessageListener

public class QuoteServer
extends Object
implements MembershipListener, MessageListener

Example of a replicated quote server. The server maintains state which consists of a list of quotes and their corresponding values. When it is started, it tries to reach other quote servers to get its initial state. If it does not receive any response after 5 seconds, it assumes it is the first server and starts processing requests.

Any updates are multicast across the cluster

Author:

Bela Ban

Constructor Summary

Constructors

Constructor and Description
QuoteServer()

Method Summary

Modifier and Type	Method and Description
void	block() Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages.
Hashtable	getAllStocks()
float	getQuote(String stock_name)
byte[]	getState() Answers the group state; e.g., when joining.
static void	main(String[] args)
void	printAllStocks()
void	receive(Message msg) Called when a message is received.
void	setQuote(String stock_name, Float value)
void	setState(byte[] state) Sets the group state; e.g., when joining.
void	start()
void	suspect(Address suspected_mbr) Called whenever a member is suspected of having crashed, but has not yet been excluded.
void	viewAccepted(View new_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

QuoteServer

public QuoteServer()

Method Detail

viewAccepted

public void viewAccepted(View new_view)

Description copied from interface: MembershipListener

Called when a change in membership has occurred. No long running actions or sending of messages 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 suspected_mbr)

Description copied from interface: MembershipListener

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()

Description copied from interface: MembershipListener

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 ExtendedMembershipListener.unblock(). Note that block() is the equivalent of reception of a BlockEvent in the pull mode.

Specified by:

block in interface MembershipListener

start

public void start()

getQuote

public float getQuote(String stock_name)
               throws Exception

Throws:

Exception

setQuote

public void setQuote(String stock_name,
                     Float value)

getAllStocks

public Hashtable getAllStocks()

printAllStocks

public void printAllStocks()

receive

public void receive(Message msg)

Description copied from interface: MessageListener

Called when a message is received.

Specified by:

receive in interface MessageListener

getState

public byte[] getState()

Description copied from interface: MessageListener

Answers the group state; e.g., when joining.

Specified by:

getState in interface MessageListener

Returns:

byte[]

setState

public void setState(byte[] state)

Description copied from interface: MessageListener

Sets the group state; e.g., when joining.

Specified by:

setState in interface MessageListener

main

public static void main(String[] args)