CryChat/crychat/server/net/ChatServer.java

package server.net;

import server.Main;
import server.util.Queue;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class ChatServer {

    private final int port;
    private volatile int n_users;
    private final Thread t;
    private ServerSocket server;
    private Queue<Integer> id_q;

    public ChatServer(int port, int max_users) {
        Main.console.info("Initializing server on port: " + port + " with max_users: " + max_users);
        this.port = port;
        n_users = 0;
        t = new Thread(() -> {
            try {
                while (true) {
                    if (n_users == max_users) continue;
                    Socket s = server.accept();
                    DataInputStream inputStream = new DataInputStream(s.getInputStream());
                    DataOutputStream outputStream = new DataOutputStream(s.getOutputStream());
                    ChatClient client = new ChatClient(id_q.deq(), s, inputStream, outputStream, this);
                    n_users++;
                    Main.console.success("Client (" + s.getRemoteSocketAddress().toString() + ") [id: " + client.id + "] connected!");
                }
            } catch (IOException e) {
                Main.console.error("An error occurred while listening for connections!");
                e.printStackTrace();
            }
        });
        id_q = new Queue<>(max_users);
        for (int i = 0; i < max_users; ++i) id_q.enq(i);
    }

    public void start() {
        try {
            server = new ServerSocket(port);
            t.start();
        } catch (Throwable e) {
            Main.console.error("An error occurred while starting the ChatServer!");
            e.printStackTrace();
        }
    }

    public void stop() {
        try {
            t.stop();
        } catch (Throwable e) {
            Main.console.error("An error occurred while stopping the ChatServer!");
            e.printStackTrace();
        }
    }

    public void disconnect(ChatClient c) {
        c.disconnect();
        id_q.enq(c.id);
        n_users--;
        Main.console.info("Disconnected client [id: " + c.id + "]");
    }
}