package clientserver;

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

public abstract class Communicator<M> {
	ObjectOutputStream oos;  // constructor sends a header (software version)
	ObjectInputStream ois;  // constructor receive the header (check for compatibility)
	
	protected Communicator(String hostAddress, int portNumber)
		throws UnknownHostException, IOException {
			this(new Socket(hostAddress, portNumber));
	}
	
	protected Communicator(Socket s) throws IOException {
	oos = new ObjectOutputStream(s.getOutputStream());
	ois = new ObjectInputStream(s.getInputStream());
}
	
	public void start() {
		startActiveProcessing();
		startReceiving();
	}
	
	void startActiveProcessing() {
		if (this instanceof Runnable)
			((new Thread((Runnable) this))).start();
	}
	
	protected void startReceiving() { // support reactive clients
		(new Thread() {
			public void run() {
					try {
						while (true)
							messageReceived(receive());
					} catch (IOException e) {
						e.printStackTrace();
					} catch (ClassNotFoundException e) {
						e.printStackTrace();
					}
			}
		}).start();
	}
	
	abstract void messageReceived(M message);
	
	M receive() throws IOException, ClassNotFoundException {  // active client calls this to wait for the next message
		return (M) ois.readObject();
	}
	
	protected void send(M message) {
		try {
			oos.writeObject(message);
		} catch (IOException e) {
			throw new RuntimeException("send failed due to " + e, e);
		}
	}
	

}