Stop and Wait Protocol using Java

StopAndWaitSender.java

package com.t4b.demo.stopnwait; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintStream; import java.net.Socket; import java.util.Scanner; public class StopAndWaitSender { public static void main(String args[]) throws Exception { StopAndWaitSender sws = new StopAndWaitSender(); sws.run(); } public void run() throws Exception { Scanner sc = new Scanner(System.in); System.out.println("Enter no of frames to be sent:"); int n = sc.nextInt(); Socket myskt = new Socket("localhost", 9999); PrintStream myps = new PrintStream(myskt.getOutputStream()); for (int i = 0; i <= n;) { if (i == n) { myps.println("exit"); break; } System.out.println("Frame no " + i + " is sent"); myps.println(i); BufferedReader bf = new BufferedReader(new InputStreamReader(myskt.getInputStream())); String ack = bf.readLine(); if (ack != null) { System.out.println("Acknowledgement was Received from receiver"); i++; Thread.sleep(4000); } else { myps.println(i); } } } }

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StopAndWaitReceiver.java

package com.t4b.demo.stopnwait; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintStream; import java.net.ServerSocket; import java.net.Socket; public class StopAndWaitReceiver { public static void main(String args[]) throws Exception { StopAndWaitReceiver swr = new StopAndWaitReceiver(); swr.run(); } public void run() throws Exception { String temp = "any message", str = "exit"; ServerSocket myss = new ServerSocket(9999); Socket ss_accept = myss.accept(); BufferedReader ss_bf = new BufferedReader(new InputStreamReader(ss_accept.getInputStream())); PrintStream myps = new PrintStream(ss_accept.getOutputStream()); while (temp.compareTo(str) != 0) { Thread.sleep(1000); temp = ss_bf.readLine(); if (temp.compareTo(str) == 0) { break; } System.out.println("Frame " + temp + " was received"); Thread.sleep(500); myps.println("Received"); } System.out.println("ALL FRAMES WERE RECEIVED SUCCESSFULLY"); } }

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Happy Exploring!