//SimpServer.java

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

public class SimpServer {
    public static void main( String[] args )  
	throws IOException, ClassNotFoundException {

	//all the socket methods throw exceptions, so instead of cluttering
	//this example with try catches, use throws...

	ServerSocket server;
	Socket connection;
	ObjectInputStream input;
	ObjectOutputStream output;
	String message;

	//1. create a server socket.  use netstat to see it.
	//bind the server to the TCP port
	server = new ServerSocket( 12345, 10 );//port, queue (max # waiting clients)

	do {
	    System.out.println( "Server waiting..." );
	    //2. listen indefinitely (block) for a connection from a client
	    connection = server.accept();   
	    //returns when connection w/client established
	    System.out.println( "Server got Connection from: " +
				connection.getInetAddress().getHostName() );
	    
	    //3. get OutputStream and InputStream objects for byte send/receive.
	    //output stream for objects for greater convenience.
	    //sockets make network IO look like file IO.
	    output = new ObjectOutputStream( connection.getOutputStream() );
	    output.flush();  //send header info?
	    
	    input = new ObjectInputStream( connection.getInputStream() );
	    
	    //server will input first
	    message = (String)input.readObject();
	    System.out.println( "Server received: " + message );
	    
	    //then output
	    message = "roger, over and out";
	    output.writeObject( message );
	    output.flush();  //?
	    
	    input.close();
	    output.close();
	    connection.close();

	} while (true);
    }
}