How can a session scope bean access an application scope bean - help

Question

Hello,
I have a JSP page that has references to an Application Scope and a Session Scope bean...
<jsp:useBean id="myWebApp" scope="application" class="com.my.web.WebApplication" />
<jsp:useBean id="myWebSession" scope="session" class="com.my.web.WebSession" />
I would like the WebSession access methods in the WebApplication ... Can/ How does the WebSession object lookup the reference to WebApplication object?

Answer 1

I don't think you should make the WebSession implement the session listener.
The session listener will be created once, at the start of the servlet context and would be listening to all sessions. So you would have one instance of the WebSession belonging to the context (though not as an attribute), and others belonging to each session. This will be confusing in your code, I think.
I would suggest having a different class act as the HttpSessionListener. Perhaps do something like this:
public class WebSessionInjector implements HttpSessionListener {
  public void  sessionCreated(HttpSessionEvent e) {
    WebApplication webApp = (WebApplication)(e.getSession().getServletContext().getAttribute("webapp"));
    WebSession mySession = new WebSession();
    mySession.setWebApplication(webApp);
    e.getSession().setAttribute("mySession", mySession);
  public void sessionDestroyed(HttpSessionEvent e) { ... }
}You may be able to use the WebApplication object itself as the listener ...
Or, you could make the WebSession implement the HttpSessionBindingListener and use the valueBound event much like the sessionCreated event above, but from inside the WebSession object:
public class WebSession implements HttpSessionBindingListener {
  public void  valueBound(HttpSessionBindingEvent e) {
    WebApplication webApp = (WebApplication)(e.getSession().getServletContext().getAttribute("webapp"));
    this.setWebApplication(webApp);
  public void valueUnbound(HttpSessionBindingEvent e) { ... }
}