Refactoring Singleton Overuse

Question

Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a co

Answer 1

I recently had to tackle a similar problem, and what I did seemed to work well for me, maybe it will help you:

(1) Group all "global" information into a single class. Let's call it Configuration.

(2) For all classes which used to use these static objects, change them to (ultimately) inherit from a new abstract base class which looks something like

abstract class MyBaseClass {
    protected Configuration config; // You can also wrap it in a property
    public MyBaseClass(Configuration config) {
        this.config = config;
    }
}

(3) Change all constructors of classes deriving from MyBaseClass accordingly. Then just create one instance of Configuration at start and pass it on everywhere.

Cons:

• You need to refactor many of your constructors and every place in which they are called
• This won't work well if you do not derive your top-level classes from Object. Well, you can add the config field to the derived class, it's just less elegant.

Pros

• Not a lot of effort to just change inheritance and constructors, and bang - you can switch all Configuration.Instance with config.
• You get rid of static variables completely; so no problems now if, for example, your application suddenly turns into a library and someone is trying to invoke multiple methods concurrently or whatever.