package org.jgroups.demos;
import org.jgroups.*;
import org.jgroups.blocks.RpcDispatcher;
import org.jgroups.util.Util;
import org.jgroups.logging.Log;
import org.jgroups.logging.LogFactory;
import java.util.Date;
import java.util.Enumeration;
import java.util.Hashtable;
/**
* 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.<p>
* Any updates are multicast across the cluster
* @author Bela Ban
*/
public class QuoteServer implements MembershipListener, MessageListener {
final Hashtable stocks=new Hashtable();
Channel channel;
RpcDispatcher disp;
static final String channel_name="Quotes";
final int num_members=1;
Log log=LogFactory.getLog(getClass());
final String props=null; // default stack from JChannel
private void integrate(Hashtable state) {
String key;
if(state == null)
return;
for(Enumeration e=state.keys(); e.hasMoreElements();) {
key=(String)e.nextElement();
stocks.put(key, state.get(key)); // just overwrite
}
}
public void viewAccepted(View new_view) {
System.out.println("Accepted view (" + new_view.size() + new_view.getMembers() + ')');
}
public void suspect(Address suspected_mbr) {
}
public void block() {
}
public void start() {
try {
channel=new JChannel(props);
disp=new RpcDispatcher(channel, this, this, this);
channel.connect(channel_name);
System.out.println("\nQuote Server started at " + new Date());
System.out.println("Joined channel '" + channel_name + "' (" + channel.getView().size() + " members)");
channel.getState(null, 0);
System.out.println("Ready to serve requests");
}
catch(Exception e) {
log.error("QuoteServer.start() : " + e);
System.exit(-1);
}
}
/* Quote methods: */
public float getQuote(String stock_name) throws Exception {
System.out.print("Getting quote for " + stock_name + ": ");
Float retval=(Float)stocks.get(stock_name);
if(retval == null) {
System.out.println("not found");
throw new Exception("Stock " + stock_name + " not found");
}
System.out.println(retval.floatValue());
return retval.floatValue();
}
public void setQuote(String stock_name, Float value) {
System.out.println("Setting quote for " + stock_name + ": " + value);
stocks.put(stock_name, value);
}
public Hashtable getAllStocks() {
System.out.print("getAllStocks: ");
printAllStocks();
return stocks;
}
public void printAllStocks() {
System.out.println(stocks);
}
public void receive(Message msg) {
}
public byte[] getState() {
try {
return Util.objectToByteBuffer(stocks.clone());
}
catch(Exception ex) {
ex.printStackTrace();
return null;
}
}
public void setState(byte[] state) {
try {
integrate((Hashtable)Util.objectFromByteBuffer(state));
}
catch(Exception ex) {
ex.printStackTrace();
}
}
public static void main(String args[]) {
try {
QuoteServer server=new QuoteServer();
server.start();
while(true) {
Util.sleep(10000);
}
}
catch(Throwable t) {
t.printStackTrace();
}
}
}