// TCP finger client - Derek Molloy...
// Usage: Finger username@host.com

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

public class Finger
{
    public static void main ( String args[] )
    {
      // Check command line paramaters

      if (args.length != 1)
      {
        System.err.println ("Invalid number of paramaters:");
	System.err.println ("Usage: Finger username@host");
        System.exit(1);
      }
      // Check for existence of @ in paramater
      else if (args[0].indexOf("@") == -1)  
      {
        System.err.println ("Invalid paramater : syntax user@host");
        System.exit(1);
      }

      // Split command line paramater at the @ character
      String username = args[0].substring(0, args[0].indexOf("@") );
      String hostname = args[0].substring(args[0].indexOf("@") +1, 
                                 args[0].length());
      try
      {
          System.out.println ("Connecting to " + hostname);

          // Create a connection to server
          Socket s = new Socket(hostname, 79);

          // Create input and output streams to socket
          PrintStream out = new PrintStream( s.getOutputStream()) ;
         
	  BufferedReader in = new BufferedReader(
			new InputStreamReader( s.getInputStream()));


          // Write username to socket output
          out.println( username );

          // Read response from socket
          String line = in.readLine();

          while (line != null)
          {
               System.out.println ( line );

               // Read next line
               line = in.readLine();
          }

          // Terminate connection
          s.close();                        
       }
       catch (SocketException e )
       {
          System.err.println ("Socket error : " + e);
       }
       catch (UnknownHostException e )
       {
          System.err.println ("Invalid host!");
       }
       catch (IOException e )
       {
          System.err.println ("I/O error : " + e);
       }
   }
}