// Server.java: The server accepts data from the client, processes it
// and returns the result back to the client
//package Chapter16;

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

public class Server
{
  // Main method
  public static void main(String[] args)
  {
    try
    {
      // Create a server socket
      ServerSocket serverSocket = new ServerSocket(8000);

      // Start listening for connections on the server socket
      Socket connectToClient = serverSocket.accept();

      // Create a buffered reader stream to get data from the client
      BufferedReader isFromClient = new BufferedReader(new
        InputStreamReader(connectToClient.getInputStream()));

      // Create a buffered writer stream to send data to the client
      PrintWriter osToClient = new PrintWriter(
        connectToClient.getOutputStream(), true);

      // Continuously read from the client and process it,
      // and send result back to the client
      while (true)
      {
        // Read a line and create a string tokenizer
        StringTokenizer st = new StringTokenizer
          (isFromClient.readLine());

        // Convert string to double
        double radius = new Double(st.nextToken()).doubleValue();

        // Display radius on console
        System.out.println("radius received from client: "
          +radius);

        // Compute area
        double area = radius*radius*Math.PI;

        // Send the result to the client
        osToClient.println(area);

        // Print the result to the console
        System.out.println("Area found: "+area);
      }
    }
    catch(IOException ex)
    {
      System.err.println(ex);
    }
  }
}