Question

I have JSF web app on glassfish using j_security_check validation with jdbcRealm on glassfish connected to MSSQL db.
Is there any way to check for example if there exists active bean with given username?
I just want to display on the web page who is online. My guesses:

1. keep variable in database and change it with login/logout. The problem rather occurs if someone didnt logout but his session expires. Than I don’t have possibility to check if he’s still logged in.
2. keep boolean variable in bean and change it with login/logout. Problem is as in previous opportunity.

Is there way to change such variable while session expires? Maybe some other approach is more common?

Answer 1

The problem rather occurs if someone didnt logout but his session expires. Than I don’t have possibility to check if he’s still logged in.

You have the possibility by implementing a HttpSessionListener:

@WebListener
public class YourUserSessionListener implements HttpSessionListener {

    @Override 
    public void sessionCreated(HttpSessionEvent event) {
        // NOOP.
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent event) {
        YourUser yourUser = event.getSession().getAttribute("yourUser");

        if (yourUser != null) {
            yourUser.logout(); // Update DB.
        }
    }

}

Where YourUser is your session scoped JSF managed bean representing the logged-in user.

Or when you’re on JSF2 (as your question history confirms), put @PreDestroy on the logout method in the session scoped JSF managed bean representing the logged-in user:

@ManagedBean
@SessionScoped
public class YourUser {

    // ...

    @PreDestroy
    public void logout() {
        // Update DB.
    }

}

This way the method will be invoked before the bean get destroyed on session expiration.