Best way to have only one instance of an object in web application.

Question

Hello,
I defined a class that provides services to my web application: subscribes user, check if user already subscrubed etc. The objects don't need to save any session information. So it is like a Stateless Session Bean (from what I've read about Session beans).
The webapp is small and I don't want to use EJBs.
What would be the best way to have one instance of the above class in my webapp ?
Would making the class static be a good method ? Using a factory ?
Is there a way to put in web.xml something that asks the container to instantiate an object that is not a servlet and place it in Application scope, so that I cann retrieve it whenever required in my app ?
Other suggestions ?
Thank you,
Vlad.

Answer 1

Hi
The best way to have only one instance is use the singleton pattern. The idea is : the class has a private
contructor, a public static method that returns an instance of this object and a static member that is false if not any instance and true if there si an instance.
To obtain one instance you can do some like
MyObject ob=MyObject.getIntance();
this method inspect the static member and returns null if true. If false set to true and return the object
via the private constructor.
You can lear more at book of Gramma .... (gang of four)
Hope this helps