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

public class serv_c
{

  public static void close_server(
    ServerSocket server )
  {
    try
    {
      server.close();
    }
    catch ( Exception exc )
    {
    }
  } // close_server

  public static void close_client(
    Socket client )
  {
    try
    {
      client.close();
    }
    catch ( Exception exc )
    {
    }
  } // close_client

  public static void close_reader(
    BufferedReader reader )
  {
    try
    {
      reader.close();
    }
    catch ( Exception exc )
    {
    }
  } // close_reader

  public static void main( String args[] )
  {
    ServerSocket server = null;
    try
    {
      server = new ServerSocket( 2747 );
    } // try
    catch ( IOException exc )
    {
      System.out.println( 
        "Kunde inte lyssna!" );
      System.exit( 1 );
    ////////////////////
    } // catch

    Socket client = null;
    try
    {
      System.out.println( 
        "Lyssnar på port 2747" );
      client = server.accept();
    } // try

    catch ( IOException exc )
    {
      System.out.println( 
        "Fel vid avlyssning!" );
      close_server( server );
      System.exit( 1 );
    ////////////////////
    } // catch
    System.out.println( 
      "OK. Klient ansluten" );

    PrintWriter writer = null;
    BufferedReader reader = null;
    try
    {
      writer = new PrintWriter(
        client.getOutputStream(), true );
      reader = new BufferedReader(
        new InputStreamReader(    
          client.getInputStream() ) );

      String buf = reader.readLine();
      while ( buf != null )
      {
        if ( buf.equals( "HEJ!" ) )
          writer.println("HEJ! HEJ!");
        else
          writer.println("NOK");
        buf = reader.readLine();
      } // while
    } // try

    catch ( Exception exc )
    {
      exc.printStackTrace();
    } // catch
    finally
    {
      if ( writer != null )
      {
        writer.close();
        close_reader( reader );
      } // if

      close_server( server );
      close_client( client );
    } // finally
  } // main
} // serv_c