// 'NetServer' + 'ServerSession.java' code file
import java.awt.*;
import java.net.*;
import java.io.*;
import java.util.*;

class NetServer extends Thread {

	static ServerSocket server;
	static Vector sessionList;

	public NetServer(int port){
		sessionList = new Vector();
		try {server = new ServerSocket(port);}
		catch(IOException e){}
	}

	public void run(){
	ServerSession session;
	Socket socket;

		while (true) {
			socket = null;
			try {

				socket = server.accept();		// blocks
				session = new ServerSession(socket);
				append(session);
				session.start();
			}
			catch(IOException e){}
		}
	}

	static int count(){return sessionList.size();}
	static void append(ServerSession ssn){sessionList.addElement(ssn);}
	static void remove(ServerSession ssn){sessionList.removeElement(ssn);}
}


class ServerSession extends Thread {

	private Socket socket;
	private DataInputStream input;
	private DataOutputStream output;

	ServerSession(Socket skt){
		socket = skt;
		try {
			input = new DataInputStream(socket.getInputStream());
			output = new DataOutputStream(socket.getOutputStream());
		}
		catch (IOException e){}
	}

	void kill(){
		NetServer.remove(this);		// drop from list
		stop();
		try {socket.close();}
		catch (IOException e){}
	}

	public void run(){		// read messages
	byte buf[];
	int size;

		if (input==null) return;

		while (true) {
			try {
				size = input.readInt();
				buf = new byte[size];
				input.read(buf,0,size);
				respond(buf);
			}
			catch (IOException e){kill();}
		}
	}


	private void send(byte buf[]){
	int size;

		try {
			size = buf.length;
			output.writeInt(size);
			output.write(buf,0,size);
		}
		catch (IOException e){kill();}
	}

	void respond(byte[] buf){
		// this is where you respond to the message
	}

}