import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

class Packet extends Thread{

    final static int MAX_CONTENT_SIZE = 4;

    String from, to;
    String content;
    int packetNo;
    boolean end;
    Receiver r;

    public Packet(String from, String to, String content, int packetNo, boolean end, Receiver r) {
        this.from = from;
        this.to = to;
        this.content = content;
        this.packetNo = packetNo;
        this.end = end;
        this.r = r;
        start();
    }

    @Override
    public void run() {
        super.run();
        try {
            Random rnd = new Random();
            Thread.sleep(rnd.nextInt(51));
            if (!content.equals("")){
                //System.out.println(this);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        try {
            r.recieve(this);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //System.out.println(this + " som dead");
    }

    @Override
    public String toString() {
        return from + "->" + to + ": " + content + "(" + packetNo + ")";
    }


}

class Receiver {
    private List<Packet> list = new ArrayList<>();
    int i = 0;

    public void recieve(Packet packet) throws InterruptedException {
        System.out.println(packet);
    }


}

class Sender {

    Receiver r;

    public Sender(Receiver r) {
        this.r = r;
    }

    public void send(String from, String to, String msg) throws InterruptedException {
        List<Packet> list = new ArrayList<>();
        for (int i = 0; i < msg.length()/Packet.MAX_CONTENT_SIZE; i++) {
            list.add(new Packet(from, to, msg.substring(i * Packet.MAX_CONTENT_SIZE, (i * Packet.MAX_CONTENT_SIZE) + Packet.MAX_CONTENT_SIZE), i, false, r));
        }
        list.add(new Packet(from, to, msg.substring(msg.length()/ Packet.MAX_CONTENT_SIZE * Packet.MAX_CONTENT_SIZE), msg.length()/ Packet.MAX_CONTENT_SIZE, true, r));
        for (int i = 0; i < list.size(); i++) {
            list.get(i).join();
        }
    }
}

public class TCPThreads {

    public static void main(String[] args) throws InterruptedException {
        Receiver r = new Receiver();
        Sender s = new Sender(r);

        s.send("A", "B", "Ahoj");
        s.send("B", "A", "Nazdar");
        s.send("A", "B", "Tie streamy na midterme sme necakali, co");
    }
}