how to accept only 1 connection in socket

Question

Hi i have this code of the server and i added the if to check if ocupado(busy) is = 0, accept socket, if its open busy = 1, so reject till the first user finish the connection, but dont work...

import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;

/**
 *
 * @author www
 */
public class ServidorTCPBasico {
static int ocupado = 0; // = busy var to check
  public static void main(String[] args) {

    try {

      // Instancia o ServerSocket ouvindo a porta 9000

      ServerSocket servidor = new ServerSocket(9000);

      System.out.println("Servidor ouvindo a porta 9000");

      while(true) {

        // o método accept() bloqueia a execução até que

        // o servidor receba um pedido de conexão
        Socket cliente = servidor.accept();
        if(ocupado == 0) { 

        int ocupado = 1;
        System.out.println("Cliente conectado: " + cliente.getInetAddress().getHostAddress());
System.out.println(ocupado);
        ObjectOutputStream saida = new ObjectOutputStream(cliente.getOutputStream());

        saida.flush();

//        saida.writeObject(new Date());
        saida.writeUTF("TEXTO TESTE PARA TRANSFERIR...");
        saida.close();

      //  cliente.close();

        }  else { 
            System.out.println("Ocupado");
          }

      }   
    }


    catch(Exception e) {

       System.out.println("Erro: " + e.getMessage());

    } 

    finally {
    }  


  }     

}

so my question is how to make the socket to accept onnly one connection per time, and THE SERVER close the connection when the user press OK in a confirm box..

the part of confirm box etc.. i will add, my problem is the "logic" or command to allow only one connection, when the client try, it refuse the connection, i will treat the refused connection in the client later

Answer 1

As per the JavaDocs for ServerSocket , you can set a backlog as the 2nd parameter. If requests exceed this backlog they are simply refused. As per this line:

The maximum queue length for incoming connection indications (a request to connect) is set to the backlog parameter. If a connection indication arrives when the queue is full, the connection is refused

So, you can try the following:

ServerSocket servidor = new ServerSocket(9000, 1);

Answer 2

You're already ensuring that, by having a single-threaded server. You can't get back to the accept() call until you've finished with the previous client. There is no need for your occupado test at all.