org.jgroups.demos

Class QuoteServer

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. When it receives a view notification it checks whether there are more members in the view than in its previous view. If this is the case, it broadcasts a request for the state to all members. Integration of different states is simply the union of all states (with the danger of overwriting mutually inconsistent state).

This mechanism allows both for fast discovery of initial servers, and - in the case of partition merging - for reintegration of existing servers. Broadcasting the state request upon every view change (only when new members are joined) causes potentially a lot of network traffic, but it is assumes that there will not be more than 5 quote servers at most.

Author: Bela Ban

Method Summary
voidblock()
HashtablegetAllStocks()
floatgetQuote(String stock_name)
byte[]getState()
static voidmain(String[] args)
voidprintAllStocks()
voidreceive(Message msg)
voidsetQuote(String stock_name, Float value)
voidsetState(byte[] state)
voidstart()
voidsuspect(Address suspected_mbr)
voidviewAccepted(View new_view)

Method Detail

block

public void block()

getAllStocks

public Hashtable getAllStocks()

getQuote

public float getQuote(String stock_name)

getState

public byte[] getState()

main

public static void main(String[] args)

printAllStocks

public void printAllStocks()

receive

public void receive(Message msg)

setQuote

public void setQuote(String stock_name, Float value)

setState

public void setState(byte[] state)

start

public void start()

suspect

public void suspect(Address suspected_mbr)

viewAccepted

public void viewAccepted(View new_view)
Copyright ? 1998-2005 Bela Ban. All Rights Reserved.