Update on yesterday’s post. Here’s a sample listener that implements the HttpSessionListener interface:

****************************************************
package com.mindseye;

import javax.servlet.http.*;
import javax.servlet.http.HttpSessionListener;

/**
* @author Aaron Johnson
* ajohnson@mindseye.com
*
* CFMXHttpSessionListener: An object that implements the HttpSessionListener
* interface, allowing CFMX developers to use session_OnStart and session_OnEnd
* events. This class can only retrieve the J2EE session ID when “Use J2EE
* session variables” is checked in CFIDE –> Administrator –> Memory
* Variables.
*/

public class CFMXHttpSessionListener implements HttpSessionListener {

public void sessionCreated(HttpSessionEvent se) {

// get the session just created
HttpSession newSession = se.getSession();

// do something with the new session (ie: log to db, write to a file, email to a friend
System.err.println(“A new session was created: session = ” + newSession.toString());
System.err.println(“Creation:” + newSession.getCreationTime());

}

public void sessionDestroyed(HttpSessionEvent se) {

// get the session just created
HttpSession newSession = se.getSession();

/* do stuff upon session end, (ie: delete items from this users shopping cart
if you’re persisting items to a db..)
*/
System.err.println(“A session was destroyed: session = ” + newSession.toString());
System.err.println(“Creation:” + newSession.getCreationTime());

}
}

****************************************************
And then to get this class to run, you must add

<listener>
  <listener-class>
    com.mindseye.CFMXHttpSessionListener
  </listener-class>
</listener>

to CFMX\wwwroot\WEB-INF\web.xml and you must copy the compiled class to the CFMX\wwwroot\WEB-INF\classes\com\mindseye\ folder. Additionally, it appears that (and this makes sense) the session we’re getting information about is the J2EE session ID, not the CFID & CFTOKEN. This means that you must have “Use J2EE session variables” checked in CFIDE –> Administrator –> Memory Variables. Restart CFMX and then you can see the results in cfusionmx\runtime\logs\default-err.log

This class would probably be way more useful if it actually did something… like log the start and end times, the id and maybe the servlet context to a database, but each developer will probably want to do something different, so I’ll leave that unfinished. I’m *not* seeing the session_OnEnd fired in my testing… anyone wanna take a guess?

Here’s a sample application_OnStart for CFMX:

****************************************************
package com.mindseye;

import javax.servlet.*;
import javax.servlet.ServletContextListener;

/**
* @author Aaron Johnson
* ajohnson@mindseye.com
*
* CFMXServletContextListener: An object that implements the ServletContextListener
* interface, allowing CFMX developers to use application_OnStart and
* application_OnEnd events.
*/
public class CFMXServletContextListener implements ServletContextListener {

public void contextDestroyed(ServletContextEvent sce) {

ServletContext sc = sce.getServletContext();

// do something on destroy()
System.err.println(“The application ‘” + sc.getServletContextName() + “‘ was destroyed”);

}

public void contextInitialized(ServletContextEvent sce) {

ServletContext sc = sce.getServletContext();

// do something on destroy()
System.err.println(“The application ‘” + sc.getServletContextName() + “‘ was started”);
}
}
****************************************************

Again, same thing, you must copy the compiled class files to cfusion\wwwroot\WEB-INF\classes\com\mindseye\, add a <listener> element to web.xml and restart CFMX. You’ll see the results in cfusion\runtime\logs\default-err.log.

I’d love to hear from Macromedia (or any other Java geeks) as to why I don’t get an results from sessionDestroyed().

Couple weeks ago some guys from Macromedia stopped by to yack with us about what we thought could be improved and/or added to the next version of CFMX. One of the things that came up a couple times was that it would be nice to have session OnStart and OnEnd functionality as well as application OnStart and OnEnd. Reading this month’s Java Developer’s Journal, it has an article on the HttpSession object (I’d link to it, but they charge for their content… too bad, I bet they’d be getting alot more traffic and readers if they’d provide their content for free), which provides multiple listener objects, HttpSessionListener, HttpSessionBindingListener, HttpSessionAttributeListener, and HttpSessionActivationListener. I don’t have CFMX here at home, but it seems like it would be possible to write a class that implements those either of those interfaces (probably the sessionCreated() and sessionDestroyed methods of the HttpSessionListener object), register that class in the web.xml of WEB-INF for your application like this:

<listener>
  <listener-class>
    com.yourApp.yourSessionListener
  </listener-class>
</listener>

Turns out you could do the same type of thing w/ javax.servlet.ServletContextListener [contextDestroyed() and contextInitialized()] and then register:

<listener>
  <listener-class>
    com.yourApp.yourApplicationListener
  </listener-class>
</listener>

in your web.xml and then… hypothetically, you’d have session OnStart, session OnEnd, application OnStart and application OnEnd just like ASP.

I’ll try it out tomorrow, unless you beat me to it.