// $Id: Gossip.java,v 1.9 2005/10/31 10:56:31 belaban Exp $package org.jgroups.demos;import org.jgroups.*;import org.jgroups.util.Util;import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.io.ByteArrayOutputStream;import java.io.ObjectOutputStream;import java.io.Serializable;import java.util.Random;import java.util.Vector;/** * Demos that tries to graphically illustrating the gossip (or pbcast) protocol: every sender periodically sends * a DRAW command to a random subset of the group members. Each member checks whether it already received the * message and applies it if not yet received. Otherwise it discards it. If not yet received, the message will * be forwarded to 10% of the group members. This demo is probably only interesting when we have a larger * number of members: a gossip will gradually reach all members, coloring their whiteboards. */public class Gossip implements Runnable, WindowListener, ActionListener, ChannelListener {    private Graphics graphics=null;    private Frame mainFrame=null;    private JPanel panel=null, sub_panel=null;    private final ByteArrayOutputStream out=new ByteArrayOutputStream();    private final Random random=new Random(System.currentTimeMillis());    private Button gossip_button, clear_button, leave_button;    private final Font default_font=new Font("Helvetica", Font.PLAIN, 12);    private final String groupname="GossipGroupDemo";    private Channel channel=null;    private Thread receiver=null;    private int member_size=1;    private final Vector members=new Vector();    private int red=0, green=0, blue=0;    private Color default_color=null;    boolean first=true;    final double subset=0.1;    Address local_addr=null;    TrafficGenerator gen=null;    long traffic_interval=0;    public Gossip(String props, long traffic) throws Exception {        channel=new JChannel(props);        channel.addChannelListener(this);        channel.setOpt(Channel.AUTO_RECONNECT, Boolean.TRUE);        traffic_interval=traffic;        if(traffic_interval > 0) {            gen=new TrafficGenerator();            gen.start();        }    }    public static void main(String[] args) {        Gossip gossip=null;        String props=null;        long traffic=0;        for(int i=0; i < args.length; i++) {            if("-help".equals(args[i])) {                System.out.println("Gossip [-traffic_interval <interval in msecs>] [-help]");                return;            }            if("-traffic_interval".equals(args[i])) {                traffic=Long.parseLong(args[++i]);                continue;            }        }        // props="UDP:PING:FD:STABLE:NAKACK:UNICAST:FRAG:FLUSH:GMS:VIEW_ENFORCER:PERF(trace=;details=true)";        /**         props="TCP(start_port=8000):" +         "TCPPING(num_initial_members=1;timeout=3000;port_range=2;"+         "initial_hosts=daddy[8000],terrapin[8000],sindhu[8000]):" +         "FD:" +         "pbcast.PBCAST(gossip_interval=5000;gc_lag=50):" +         "UNICAST:" +         "FRAG:" +         "pbcast.GMS";         // "PERF(trace=true;details=true)";         **/        props="UDP(mcast_addr=224.10.10.100;mcast_port=5678;ip_ttl=32):" +                "PING:" +                // "FD(shun=true;timeout=5000):" +                "pbcast.FD(timeout=3000):" +                "VERIFY_SUSPECT(timeout=2000;num_msgs=2):" +                "pbcast.PBCAST(desired_avg_gossip=8000;mcast_gossip=true;gc_lag=30;max_queue=20):" +                "UNICAST:" +                "FRAG:" +                "pbcast.GMS"; // :" + // ;join_timeout=20):" +        // "PERF(trace=true;details=true)";        try {            gossip=new Gossip(props, traffic);            gossip.go();        }        catch(Exception e) {            System.err.println(e);            System.exit(0);        }    }    private void selectColor() {        red=(Math.abs(random.nextInt()) % 255);        green=(Math.abs(random.nextInt()) % 255);        blue=(Math.abs(random.nextInt()) % 255);        default_color=new Color(red, green, blue);    }    public void go() {        try {            channel.connect(groupname);            local_addr=channel.getLocalAddress();            startThread();            mainFrame=new Frame();            panel=new MyPanel();            sub_panel=new JPanel();            mainFrame.setSize(250, 250);            mainFrame.add("Center", panel);            clear_button=new Button("Clear");            clear_button.setFont(default_font);            clear_button.addActionListener(this);            gossip_button=new Button("Gossip");            gossip_button.setFont(default_font);            gossip_button.addActionListener(this);            leave_button=new Button("Leave & Exit");            leave_button.setFont(default_font);            leave_button.addActionListener(this);            sub_panel.add("South", gossip_button);            sub_panel.add("South", clear_button);            sub_panel.add("South", leave_button);            mainFrame.add("South", sub_panel);            mainFrame.addWindowListener(this);            mainFrame.setVisible(true);            setTitle();            graphics=panel.getGraphics();            graphics.setColor(default_color);            mainFrame.setBackground(Color.white);            mainFrame.pack();            gossip_button.setForeground(Color.blue);            clear_button.setForeground(Color.blue);            leave_button.setForeground(Color.blue);        }        catch(Exception e) {            System.err.println(e);            return;        }    }    void startThread() {        receiver=new Thread(this, "GossipThread");        receiver.setPriority(Thread.MAX_PRIORITY);        receiver.start();    }    void setTitle() {        String title="";        if(local_addr != null)            title+=local_addr;        title+=" (" + member_size + ") mbrs";        mainFrame.setTitle(title);    }    public void run() {        Object tmp;        Message msg=null;        Command comm;        boolean fl=true;        Vector mbrs;        ObjectOutputStream os;        while(fl) {            try {                tmp=channel.receive(0);                // System.out.println("Gossip.run(): received " + tmp);                if(tmp == null) continue;                if(tmp instanceof View) {                    View v=(View)tmp;                    member_size=v.size();                    mbrs=v.getMembers();                    members.removeAllElements();                    for(int i=0; i < mbrs.size(); i++)                        members.addElement(mbrs.elementAt(i));                    if(mainFrame != null)                        setTitle();                    continue;                }                if(tmp instanceof ExitEvent) {                    // System.out.println("-- Gossip.main(): received EXIT, waiting for ChannelReconnected callback");                    break;                }                if(!(tmp instanceof Message))                    continue;                msg=(Message)tmp;                comm=null;                Object obj=msg.getObject();                // System.out.println("obj is " + obj);                if(obj instanceof Command)                    comm=(Command)obj;                else                    if(obj instanceof Message) {                        System.out.println("*** Message is " + Util.printMessage((Message)obj));                        Util.dumpStack(true);                    }                    else {                        if(obj != null)                            System.out.println("obj is " + obj.getClass() + ", hdrs are" + msg.printObjectHeaders());                        else                            System.out.println("hdrs are" + msg.printObjectHeaders());                        Util.dumpStack(true);                    }                switch(comm.mode) {                    case Command.GOSSIP:                        if(graphics != null) {                            colorPanel(comm.r, comm.g, comm.b);                            comm.not_seen.removeElement(local_addr);                            if(comm.not_seen.size() > 0) { // forward gossip                                Vector v=Util.pickSubset(comm.not_seen, subset);                                out.reset();                                os=new ObjectOutputStream(out);                                os.writeObject(comm);                                os.flush();                                for(int i=0; i < v.size(); i++) {                                    channel.send(new Message((Address)v.elementAt(i), null, out.toByteArray()));                                }                            }                        }                        break;                    case Command.CLEAR: