import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

/*
 * Sample class to illustrate how to setup a server that listens
 * on a dedicated port for incoming TCP connections.
 */
public class MyServer
{
    // port to bind to
    static int port = 1025;
    static boolean running = false;
    
    // standard program entry point
    public static void main(String args[])
    {
        // The communication attempt must be embedded in a 'try-catch' block
        // to catch the many errors that could occur during communications
        try
        {
            // Starting server by binding to requested port if possible.
            ServerSocket server = new ServerSocket(port);
            System.out.println("Server started: " + server);
            
            // Setting up infinite loop to handle multiple client 
            // connections in sequence.
            running = true;
            
            while (running)
            {
                // Waiting for incoming connection in a blocking call
                Socket socket = server.accept();
                System.out.println("Connected: " + socket);

                // Now handling the client. It is embedded in its own
                // try-catch block to keep the server running even if
                // the client experiences an error (e.g. timeout).
                try
                {
                    processClient(socket);
                }
                catch(IOException ioe)
                {
                    System.err.println("Error: " + ioe.getMessage());
                }
                
                // We are done so we close the client connection. The server
                // itself will remain running, waiting for the next client
                // to connect t the top of the loop.
                socket.close();
            }
            
            // Closing down the server. At this time this statement is
            // unreachable (which should change in improved versions). 
            server.close();
            System.out.println("Server is now down");
        }
        catch (IOException e)
        {
            // Printing error message for all IO exceptions
            e.printStackTrace();
        }
    }

    private static void processClient(Socket socket) throws IOException
    {
        // Setup timeout (in milli-seconds) for blocking calls
        socket.setSoTimeout(10000);
        
        // Setting up IO stream to/from the connected client
        BufferedReader in = new BufferedReader(
                                new InputStreamReader(
                                    socket.getInputStream()));
        PrintWriter out = new PrintWriter(
                              new OutputStreamWriter(
                                  socket.getOutputStream()));
        System.out.println("IO setup complete.");
        
        // Now processing the data from the client
        String line = in.readLine();
        if (line.equals("stopserver"))
        {
            running = false;
        }
        else
        {
            out.println("Bert's Echo: " + line);
            out.flush();
        }
        
        // closing IO streams
        in.close();
        out.close();
    }
}