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

/**
 * Example of how to make a very simple java server.
 * Run this as: java ServerListen <port>
 * 
 * The server binds to a port, and accepts connection.
 * It prints out what each client sends, and then
 * closes the connection without responding.
 *
 * @author Rimon Barr
 * @version 1.0, 02/11/99
 */
public class ServerListen {
  public static void main(String args[]) {
    try {
      // decode port number from command line
      int port=Integer.valueOf(args[0]).intValue();
      // create server socket on that port
      ServerSocket ss=new ServerSocket(port);
      // process connections forever
      while (true) {
        System.out.println("Listening on port "+port);
        // listen for incoming connections
        Socket s=ss.accept();
        // process connection (no thread used here,
        //   but usually we use a thread, because processing
        //   may take a long time)
        dump(s.getInputStream(), System.out);
        // close the socket, because it could be a while
        // before the next connection comes in (plus
        // we don't want to wait for garbage collection,
        // therefore s=null is not sufficient)
        s.close();
        s=null;
      }
    }
    catch (NumberFormatException e) {
      System.err.println("Invalid port number: "+args[0]);
    }
    catch (ArrayIndexOutOfBoundsException e) {
      System.err.println("Must pass in a port number");
    }
    catch (IOException e) {
      System.err.println(e);
    }
  }

  /**
   * Dump one stream into another
   * @param i input stream
   * @param o output stream
   * @exception IOException thrown if either the input or output
   *   streams have an error
   */
  public static void dump(InputStream i, OutputStream o) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(i));
    PrintWriter out = new PrintWriter(o);
    String l = in.readLine();
    while(l!=null) {
      out.println(l);
      l=in.readLine();
    }
  }
}