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/* Copyright (c) 2006, Jorg Liebeherr, University of Toronto     	   */
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/** HelloWorld_InterceptCallBack
 *
 *       The HyperCast HelloWorld programs demonstrate various aspects of
 *       the HyperCast API.  The programs create an overlay socket that 
 *       sends and receives messages. 
 *
 *       In HelloWorld_InterceptCallBack takes advantage of the interception 
 *       callback. The interception callback provides access to messages before they 
 *       forwarded by the overlay socket. 
 *       This file corresponds to an example program in the HyperCast API description 
 *       (see Chapter:  "API - The Basics", Section: "The HelloWorld program"). 
 * 
 *       The file is a bit more complex than the example in the chapter.
 *
 * @author HyperCast Team
 * @version 2005 (version 3.0)
 *
 */


import hypercast.*;

public class HelloWorld_InterceptCallBack implements I_ReceiveCallback , I_InterceptionCallback {
	
	//	The string we send 
	String MyString = new String("Hello World");
	
	//	The overlay socket 
	I_OverlaySocket MySocket = null;
	
	//	The configuration object
	HyperCastConfig ConfObj = null;
	
	public static void main(String[] args) {
		
		// Create a new HelloWorld_CallBack instance 
		HelloWorld_InterceptCallBack hw = new HelloWorld_InterceptCallBack();
		
	}
	
	public I_OverlayMessage  InterceptionCallback (I_OverlayMessage msg) {
		
		// Timestamp
		String Time = Long.toString(System.currentTimeMillis());
		Time = Time.substring(Time.length()-6, Time.length());
		
		// Modify payload of the message by adding local address and timestamp
		String ChangedString = new String(msg.getPayload()) + 
		"\n --> LA: " + MySocket.getLogicalAddress().toString()+ "\t Time: " + Time;
		msg.setPayload(ChangedString.getBytes());
		
		//System.out.println("InterceptionCallback: " + ChangedString);
		
		return msg;
	}
	
	public void ReceiveCallback (I_OverlayMessage msg) {
		
		// Extract the payload 
		byte[] data = msg.getPayload();
		
		// Print the payload (Skip messages sent by this program) 
		if(!msg.getSourceAddress().equals(MySocket.getLogicalAddress()))
			System.out.println("Received: "+ new String(data));
	}
	
	public  HelloWorld_InterceptCallBack () {
		
		//	Create a configuration object
		ConfObj = HyperCastConfig.createConfig("hypercast.xml");
		
		// Create an overlay socket with the configuration object
		MySocket=ConfObj.createOverlaySocket(this, null, this);
		
		// Join the overlay network 
		MySocket.joinOverlay();
		
		// Print the logical address */ 
		String MyLogicalAddress = MySocket.getLogicalAddress().toString();
		System.out.println("My Logical address is " + MyLogicalAddress + ".");
		
		// Repeat forever
		for(int i=1;i<100;i++) {
			
			// wait 2 seconds 	
			try {
				Thread.sleep(2000);
			} catch (InterruptedException e) {}	
			
			// Timestamp
			String Time = Long.toString(System.currentTimeMillis());
			Time = Time.substring(Time.length()-6, Time.length());
			
			// Add logical address and timestamp, convert the string to a byte array and create a message
			byte[] MyData = (MyString + "\n --> LA: " + MySocket.getLogicalAddress().toString()+ 
					"\t Time: " + Time).getBytes(); 
			I_OverlayMessage MyMessage = MySocket.createMessage(MyData);
			
			// The message is sent to all members of the overlay //
			MySocket.sendToAll(MyMessage);
			System.out.println("<HelloWorld> message sent.");
		}
		MySocket.closeSocket();
	}
}