Activatable Servers and Remote References [RMI]

Question

Hello everyone,
I'm wondering if there's a way to know, on an activatable server, how many clients have an active reference to that and their id. I need to know exactly who did not renew his lease with the server, and once I know it I can remove that client from a list of logged-in client..
example:
client "user1" gets a remote reference of the activatable server, that adds "user1" to a logged-in-list I made (like a online userlist in a forum). suddenly user1 crashes without invoking "logout" method (and for the userlist he's still online!).
Once the lease for user1 expires, the activatable servers decreases the remoteRef count.
I'd like to associate the client username with the remote reference or the lease in some way, so once a client lease is not renewed I know for sure who I've to remove with the server from the online userlist..
Hope you can understand my problem, thanks in advance
Edited by: Guguz on 28-dic-2010 6.44

Answer 1

Each time a client connects to the login server, I give him a new activatable server.A new server. Making it activatable is pointless: you're creating it dynamically per client. Only the login server needs to be activatable. It goes something like this, modulo typos:
public interface Login extends Remote
  Session login(String username, char[] password) throws RemoteException;
public class LoginImpl extends Activatable implements Login
public interface Session extends Remote
  // your session API here
  void logout() throws RemoteException; // explicit logout
public class Session extends UnicastRemoteObject implements Session, Unreferenced
  // ... implementation of your session API
  // Unreferenced.unreferenced()
  public void unreferenced()
    // Log the enforced logout via unreferenced()
    logout();
  // logout()
  public void logout()
    // Log the logout
    // call UnicastRemoteObject.unexportObject(this, true);
    // and do whatever else you have to do when a client logs out
In the activatable unreferenced methodIn the Unreferenced.unreferenced() method
then I can put the "logout user".And wherever else it should go.
And this should prevent crashes right ?Wrong. It won't prevent crashes. It will detect them.