Network Server Program

This assignment involves creating a Java network server program that can handle basic arithmetic operations (addition, subtraction, multiplication, and division). The server accepts requests from clients, processes them, and sends back the results. The server uses sockets for communication and handles potential errors such as invalid input or division by zero. The code is well-structured and uses enums for better readability and maintainability. The solution demonstrates a fundamental understanding of network programming concepts in Java. The provided code is a complete, functional solution to the assignment.

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package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
/**
* Support add, subtraction, multiplication, division
* @author hluu
*
*/
public class MyServer {
enum OPERATOR { ADD, SUB, MULT, DIV };
public static final int PORT_NO = 12345;
/**
* @param args
* @throws IOException
* @throws InterruptedException
*/
public static void main(String[] args) throws IOException, InterruptedException {
ServerSocket serverSocket = new ServerSocket(PORT_NO);
System.out.println("... server is accepting request");
while (true) {

Socket socket = serverSocket.accept();
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line = reader.readLine();
if (line.trim().startsWith("EXIT")) {
System.out.println("... server shutting down ...");
socket.close();
break;
} else {
System.out.println("Got Request " + line);
processRequest(socket, line);
}
}
System.out.println("... closing server socket ...");
serverSocket.close();
}
private static void processRequest(Socket socket, String line) throws IOException, InterruptedException {
PrintWriter pw = new PrintWriter(socket.getOutputStream());
String[] tokens = line.split(" ");
String operator = tokens[0].trim();
try {
Double operand1 = Double.valueOf(tokens[1].trim());
Double operand2 = Double.valueOf(tokens[2].trim());
System.out.println(operand1);System.out.println(operand2);

double result = 0;
OPERATOR op = OPERATOR.valueOf(operator.toUpperCase());
switch (op) {
case ADD:
result = operand1 + operand2;
break;
case SUB:
result = operand1 - operand2;
break;
case MULT:
result = operand1 * operand2;
break;
case DIV:
result = operand1 / operand2;
break;
default:
pw.println("invalid operand: " + line);
pw.flush();
socket.close();
return;
}
System.out.println("Response: " + result );
pw.println(result);
} catch (NumberFormatException e) {
pw.println("invalid operand: " + line);
}
pw.flush();
socket.close();
}
}