/** When receive a message, analyze message content and then execute the command: Draw or Clear */
public void receive(Message msg) {
byte[] buf = msg.getRawBuffer();
if (buf == null) {
System.err.println(
"["
+ channel.getAddress()
+ "] received null buffer from "
+ msg.getSrc()
+ ", headers: "
+ msg.printHeaders());
return;
}
try {
DrawCommand comm =
(DrawCommand)
Util.streamableFromByteBuffer(
DrawCommand.class, buf, msg.getOffset(), msg.getLength());
switch (comm.mode) {
case DrawCommand.DRAW:
if (drawPanel != null) drawPanel.drawPoint(comm);
break;
case DrawCommand.CLEAR:
clearPanel();
default:
System.err.println("***** received invalid draw command " + comm.mode);
break;
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Init JWhiteBoard interface
*
* @throws Exception
*/
public void go() throws Exception {
if (!noChannel && !useState) channel.connect(groupName);
mainFrame = new JFrame();
mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
drawPanel = new DrawPanel(useState);
drawPanel.setBackground(backgroundColor);
subPanel = new JPanel();
mainFrame.getContentPane().add("Center", drawPanel);
clearButton = new JButton("Clean");
clearButton.setFont(defaultFont);
clearButton.addActionListener(this);
leaveButton = new JButton("Exit");
leaveButton.setFont(defaultFont);
leaveButton.addActionListener(this);
subPanel.add("South", clearButton);
subPanel.add("South", leaveButton);
mainFrame.getContentPane().add("South", subPanel);
mainFrame.setBackground(backgroundColor);
clearButton.setForeground(Color.blue);
leaveButton.setForeground(Color.blue);
mainFrame.pack();
mainFrame.setLocation(15, 25);
mainFrame.setBounds(new Rectangle(250, 250));
if (!noChannel && useState) {
channel.connect(groupName, null, stateTimeout);
}
mainFrame.setVisible(true);
}
/** Clear all the content on a whiteboard */
public void clearPanel() {
if (drawPanel != null) drawPanel.clear();
}
/** Set state of the Group */
public void setState(InputStream istream) throws Exception {
drawPanel.readState(istream);
}
/** Get state of the Group */
public void getState(OutputStream ostream) throws Exception {
drawPanel.writeState(ostream);
}