Server.java

/*********************
* Socket Server
* @file Server.java
* @author Wangai
**********************/

import java.net.*;
import java.io.*;

public class Server extends Thread {
   private ServerSocket serverSocket;
   
   public Server(int port) throws IOException {
      serverSocket = new ServerSocket(port);
      serverSocket.setSoTimeout(1000000);
   }

   public static void main(String [] args) {
      int port = Integer.parseInt(args[0]);
      try {
         // ? do this in a seperate process?
         Thread t = new Server(port);
         t.start();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }

   public void run() {

      while(true) {

         try {

            System.out.println("Waiting for client on port " + 
               serverSocket.getLocalPort());

            Socket server = serverSocket.accept();

            System.out.println("Just connected to " + server.getRemoteSocketAddress());

            DataInputStream input = new DataInputStream(server.getInputStream());
            DataOutputStream output = new DataOutputStream(server.getOutputStream());
            
            // initial interaction ** send menu
            output.writeUTF("\n\nSERVER>\n" + menu());
            
            int service = input.readInt();
            int input1 = input.readInt();
            int input2 = input.readInt();

            /*
            System.out.println("service: " + service);
            System.out.println("input1: " + input1);
            System.out.println("input2: " + input2);
            */

            do {
               
               // ** evaluate request

               if (service == 0) {
                  break; // from do while
               } else if (service == 1) {

                  output.writeUTF("\n\nSERVER>\n" + menu());

               } else if (service == 2) {

                  output.writeUTF("SERVER>\n\t " + add(input1, input2));

               } else if (service == 3) {

                  output.writeUTF("SERVER>\n\t " + diff(input1, input2));
                  
               } else if (service == 4) {

                  output.writeUTF("SERVER>\n\t " + mult(input1, input2));
                  
               } else if (service == 5) {

                  output.writeUTF("SERVER>\n\t " + qout(input1, input2));
                  
               } else {
                  output.writeUTF("SERVER>\n\t " + "invalid choice");

               }

               
               service = input.readInt();
               input1 = input.readInt();
               input2 = input.readInt();

            } while (service != 0);

            output.writeUTF("SERVER>\n\t " + "Thank you for connecting to " + server.getLocalSocketAddress());

            server.close();
            
            
            
         } catch (SocketTimeoutException s) {

            System.out.println("Socket timed out");
            break;

         } catch (IOException e) {

            e.printStackTrace();
            break;

         }
      }
   }
   

   private String menu() {
      return "\tMath Server\n***************************\nchoose a number for the coresponding service\nthen send response in this format\n\n\tservice: (int)\n\tinput1: (int)\n\tinput2: (int)\n\n 0. Quit\n 1. Print this help message\n 2. Addition\n 3. Subtraction\n 4. Multiplication\n 5. Division";
   }

   private int add(int a, int b) {
      return a + b;
   }

   private int diff(int a, int b) {
      return a - b;
   }

   private int mult(int a, int b) {
      return a*b;
   }

   private double qout(int a, int b) {
      return (double)a/b;
   }
}