org.jgroups.demos.Topology Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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package org.jgroups.demos;
import org.jgroups.Address;
import org.jgroups.JChannel;
import org.jgroups.Receiver;
import org.jgroups.View;
import java.awt.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.util.ArrayList;
/**
* Demonstrates the membership service. Each member is represented by a rectangle that contains the
* addresses of all the members. The coordinator (= oldest member in the group) is painted in blue.
* New members can be started; all existing members will update their graphical appearance to reflect
* the new membership. When the coordinator itself is killed, another one will take over (the next in rank).
* A nice demo is to start a number of Topology instances at the same time. All of them will be blue (all are
* coordinators since they don't find each other). Then the MERGE3 protocol sets in and only one will retain
* its coordinator role.
* @todo Needs to be ported to Swing.
* @author Bela Ban
*/
public class Topology extends Frame implements WindowListener {
private final java.util.List
members=new ArrayList<>();
private final Font myFont;
private final FontMetrics fm;
private final Color node_color=new Color(250, 220, 100);
private boolean coordinator=false;
private static final int NormalStyle=0;
private static final int CheckStyle=1;
private JChannel channel;
private Object my_addr=null;
private String props="udp.xml";
private final String name;
private static final String channel_name="FD-Heartbeat";
public Topology(String props, String name) {
this.props=props;
this.name=name;
addWindowListener(this);
fm=getFontMetrics(new Font("Helvetica", Font.PLAIN, 12));
myFont=new Font("Helvetica", Font.PLAIN, 12);
}
public void addNode(Address member) {
Address tmp;
for(int i=0; i < members.size(); i++) {
tmp=members.get(i);
if(member.equals(tmp))
return;
}
members.add(member);
repaint();
}
public void removeNode(Object member) {
Object tmp;
for(int i=0; i < members.size(); i++) {
tmp=members.get(i);
if(member.equals(tmp)) {
members.remove(members.get(i));
break;
}
}
repaint();
}
public void drawNode(Graphics g, int x, int y, String label, int style) {
Color old=g.getColor();
int width, height;
width=fm.stringWidth(label) + 10;
height=fm.getHeight() + 5;
g.setColor(node_color);
g.fillRect(x, y, width, height);
g.setColor(old);
g.drawString(label, x + 5, y + 15);
g.drawRoundRect(x - 1, y - 1, width + 1, height + 1, 10, 10);
if(style == CheckStyle) {
g.drawRoundRect(x - 2, y - 2, width + 2, height + 2, 10, 10);
g.drawRoundRect(x - 3, y - 3, width + 3, height + 3, 10, 10);
}
}
public void drawTopology(Graphics g) {
int x=20, y=50;
String label;
Dimension box=getSize();
Color old=g.getColor();
if(coordinator) {
g.setColor(Color.cyan);
g.fillRect(11, 31, box.width - 21, box.height - 61);
g.setColor(old);
}
g.drawRect(10, 30, box.width - 20, box.height - 60);
g.setFont(myFont);
for(int i=0; i < members.size(); i++) {
label=members.get(i).toString();
drawNode(g, x, y, label, NormalStyle);
y+=50;
}
}
public void paint(Graphics g) {
drawTopology(g);
}
/* ------------ Callbacks ------------- */
public void coordinatorChosen() {
coordinator=true;
repaint();
}
public void windowActivated(WindowEvent e) {
}
public void windowClosed(WindowEvent e) {
}
public void windowClosing(WindowEvent e) {
setVisible(false);
dispose();
channel.close();
}
public void windowDeactivated(WindowEvent e) {
}
public void windowDeiconified(WindowEvent e) {
}
public void windowIconified(WindowEvent e) {
}
public void windowOpened(WindowEvent e) {
}
public void start() throws Exception {
channel=new JChannel(props).name(name);
channel.setReceiver(new Receiver() {
public void viewAccepted(View view) {
setInternalState(view.getMembers());
}
public void setInternalState(java.util.List mbrs) {
members.clear();
for(Address mbr : mbrs)
addNode(mbr);
coordinator=mbrs.size() <= 1 || (mbrs.size() > 1 && mbrs.iterator().next().equals(my_addr));
repaint();
}
});
channel.connect(channel_name);
my_addr=channel.getAddress();
if(my_addr != null)
setTitle(my_addr.toString());
pack();
setVisible(true);
}
public static void main(String[] args) {
String name=null, props="udp.xml";
for(int i=0; i < args.length; i++) {
if(args[i].equals("-name")) {
name=args[++i];
continue;
}
if(args[i].equals("-props")) {
props=args[++i];
continue;
}
System.out.println("Topology [-props config file] [-name name]");
return;
}
try {
Topology top=new Topology(props, name);
top.setLayout(null);
top.setSize(240, 507);
top.start();
}
catch(Exception e) {
e.printStackTrace();
System.exit(0);
}
}
}