design strategy question

[cyber]

i use to develop my web-apps using struts, i created a singleton to hold all the logged user, so that i can check for double login and report current logged users. There was one thing thats very useful to me, the SessionListener, wherein i trap session expiration w/c in turn removes the user from the list of my singleton class.

now the problem is how will i design this using Spring MVC.

in struts after i initialized my singleton class i could just do a UserList.add(), UserList.remove(), UserList.getUsers(), etc from anywhere/from any java class of my application and will get the correct data & functionality.

whats the proper way to design this in Spring? pls help me.

.... thanks a lot again in advance. you guys have been very helpful in my transition from struts to spring.

[Rod Johnson]

Write the user tracking service as a normal object, configure it with Spring and inject it where it's needed. For example, you could inject it into a superclass Spring MVC controller.

I would not recommend the traditional Singleton approach, regardless of whether you use Spring. It typically creates testing difficulties, for example.