Question

I’m storing all established HTTPSession objects in a hash-map. Is
there anyway of determining whether a HTTPSession is still valid
before en-queuing a message?

Example: if I am iterating over the hash-
map, I only want to enqueue messages for HTTPSession objects that are
valid.

UPDATE

If anyone is interested, I needed this logic with the use of gwt-comet. The solution (as Tomasz Nurkiewicz pointed out) can be found at the bottom this page.

Answer 1

Unfortunately there is no explicit API for this. But it is easy to workaround in clean and elegant manner.

Implement HttpSessionListener storing every newly created session in a concurrent map and removing it when session is destroyed. This way your map will always contain only valid sessions. Much cleaner, don’t you think?

public class SessionStoringListener implements HttpSessionListener {

    private Map<String, HttpSession> sessions = new ConcurrentHashMap<String, HttpSession>();

    @Override
    public void sessionCreated(HttpSessionEvent httpSessionEvent)
    {
        HttpSession session = httpSessionEvent.getSession();
        sessions.put(session.getId(), session);
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent httpSessionEvent)
    {
        sessions.remove(httpSessionEvent.getSession().getId());
    }
}