Thursday, March 25, 2010

Singleton vs Class method

I want to tell you before go on through the detail that following article is based on Java. Different implemented language might not have the similar behavior.

Singleton or Class method ?

This topic might too old for some of you but I always was reminded to this issue when I was going to write some method just do some algorithms - take inputs, processing, return output.

We will find many discussions on this issue if we do googling. Below this are what I conclude those discussions for myself.
  1. Singleton provides typing. You can subclassing or passing it around whatever you can do to an object-oriented instance you can do to Singleton object.
  2. Singleton provides state which a lot of you may think it is disgusting.
  3. Singleton provides lazy-initialization. You have not to have it on your memory until you are really want it.
  4. You can have many instances of Singleton-type. Also can limit number of them. While you can not do this with Class method.
I'm going to update this if I find more distinction points

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