// Connection.java -- socket wrapper for text-based IO operations
//
// author :  Scott W. Matey
//


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


public class Connection extends Object implements Runnable {

  public Socket socket;
  InputStream instream;
  PrintStream outstream;
  public Thread listener = null;
  public boolean closed = false;

  // Initialize with already-opened socket
  public Connection (Socket s) {
    socket = s;
    try {
      instream = socket.getInputStream ();
      outstream = new PrintStream (socket.getOutputStream (), true);
      }
    catch (Exception e)
      System.err.println ("Connection() exception:\n" + e);
    }

  // Open a new socket on the given host and port
  public Connection (String host, int port) 
  throws IOException, UnknownHostException  {
    this (new Socket (host, port));
    }

  // Close the socket.
  public void close () {
    if (! closed)  {
      if (listener != null) {
        listener.stop ();
        listener = null;
        }
      try {
        socket.close ();
        closed = true;
        }
      catch (Exception e)
        System.err.println ("Connection.close() exception:\n" + e);
      }
    }

  // Write string to socket
  public void print (String s) {
    outstream.print (s);
    outstream.flush ();
    }
    
  // Read line of input from socket
  public String read () throws EOFException {
    StringBuffer buff = new StringBuffer (512);
    int b = 0;
    do {
      try {
        b = instream.read ();
        }
      catch (Exception e)
        System.err.println ("Connection.read() exception:\n" + e);
      if (b == -1)
        throw new EOFException();
      else
        buff.append ((char)b);
      } while (b != '\n');
    return buff.toString();
    }

  // Default run method is to listen for input and call notifyInput.
  // Execution stops when EOF is reached or something closes the connection.
  public void run () {
    String s;
    while (! closed) {
      try
        s = read ();
      catch (EOFException e) {
        return;
        }
      notifyInput (s);
      }
    }

  // Default input notify method ought to be overridden by subclasses.
  public void notifyInput (String s) {
    }

  // Start thread to listen for input on socket.
  public void listen () {
    if (listener == null)
      listener = new Thread (this);
    listener.start ();
    }


  }  // end of class Connection