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.netarchitecturebusiness-logic

Buisness layer helper objects

I have multiple objects that are used by several classes in my BL.

I'm tring to understand how those objects should be instansiated and where to store them.

I don't want to pass them from the Service layer. My thoughs are to create a singleton class in the BL and all the others would use it. Is it a reasonable solution? I know many think of the singleton as an anti patten.

Thanks

Solution

  • Don't use singleton or static. It prevents your class from dependency injected and inflexible. I.e: you cannot change the class behavior based on component.

    The best is to use constructor injection:

    public class Usage{
    public Usage(Component1 comp1, Component2 comp2){ /*param assignment*/ }
    private Component1 comp1;
    private Component2 comp2;

    //using comp1 and comp2
}

    Or if you think that it is bothersome for object composition, you can use default object creation, that is commonly used by .Net.

    public class Usage{
    public Component1 Comp1 = new Component1();
    public Component2 Comp2 = new Component2();

    //using Comp1 and Comp2
}

    The benefit is, you can change Components with it's inheritance, or you can use interface as declaration instead for better flexibility.