datagramclient.java

ssd8 exercise 3 Write a simple datagram client/server in Java and a tcp client/server also in java

import java.net.*;
import java.util.*;
/*
 * Created on 2008-4-12
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */

/**
 * @author Guest
 *
 * TODO To change the template for this generated type comment go to
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 */
public class DatagramClient {
	
	/*
	 * Define the default port for the packet send to.
	 */
	private static int defaultPort = 8000;
	
	/*
	 * Define the size of buffer to make sure that one packet contain one byte.
	 */
	private static int bufferSize = 1;
	
	/*
	 * To make sure send-and-echo should be repeated 1000 times.
	 */
	private static int sendTimes = 1000;
	
   /*
    * The main(String[]) method.
    */
	public static void main(String[] args) {
		
		/*
		 * Record the current send-and-echo times 
		 */
		int count;
		
		/*
		 * Record the the number of packets lost and duplicated.
         */
		int lostAndDuplicated = 0;
		
		/*
		 * Contain the average round trip time.
		 */
		float avgRtt;
		
		/*
		 * Sign the begining time of the whole send-and echo process. 
		 */
		Date start;
		
		/*
		 * Sign the ending time of the whole send-and echo process. 
		 */
		Date stop;
		
		/*
		 * Declarate the send byte. 
		 */
		byte sendBuffer[] = new byte[bufferSize];
		
		/*
		 * Declarate the receive byte. 
		 */
		byte receiveBuffer[] = new byte[bufferSize];
		
		/*
		 * The datagram send packet
		 */
		DatagramPacket sendPacket;
		
		/*
		 * The datagram receive packet
		 */
		DatagramPacket receivePacket;
		
		/*
		 * The datagram client Socket.
		 */
		DatagramSocket clientSocket;
		
		/*
		 * The ip address of the server.
		 */
		InetAddress IPAdd;
		
		try
		{
			
			clientSocket = new DatagramSocket();
			IPAdd = InetAddress.getByName("127.0.0.1");
			clientSocket.setSoTimeout(1000);
			sendBuffer[0] = 0;
			start = new Date();
			for(count =0;count < sendTimes;count++)
			{
			 sendPacket = new DatagramPacket(sendBuffer,bufferSize,IPAdd,defaultPort);
			 receivePacket = new DatagramPacket(receiveBuffer,receiveBuffer.length);
			 clientSocket.send(sendPacket);
			 clientSocket.receive(receivePacket);
			 while(receiveBuffer[0] != sendBuffer[0])
			 {
			 	System.err.println("Transmit error!");
			 	count--;
			 	
			 	lostAndDuplicated ++;
			 }
			if(sendBuffer[0] < 127)
			{
				sendBuffer[0]++;
			}
			else
			{
				sendBuffer[0] = 0;
			}
			}
			stop = new Date();
			avgRtt = (float)(stop.getTime() - start.getTime()) / sendTimes;
			System.out.println("The average round trip time is: " + avgRtt + " vs");
			System.out.println("The number of packets lost and duplicated is: " + lostAndDuplicated);
		
			clientSocket.close();
		}catch(Exception e){
			
			e.printStackTrace();
			System.err.println("Error!");
			
		}
	}
}