Singleton Pattern

Singleton Pattern 

Gamma Categorization: Creational Design Patten
Summary: When it makes sense to only hae one instance of a component in the system, or the construction is expensive, or we want to prevent aditional copies creation.

Sample Code

Problem: We need to initialise a property only once.

Singleton Class

public sealed class Singleton

{

    public long Ticks { get; private set; }

    public static Singleton Instance { get { return lazy.Value; } }

    private static readonly Lazy<Singleton> lazy = new Lazy<Singleton> (() => new Singleton());

    private Singleton() 

    {

        this.Ticks = DateTime.Now.Ticks;

    }

}

Usage

WriteLine(Singleton.Instance.Ticks);

WriteLine(Singleton.Instance.Ticks);

WriteLine(Singleton.Instance.Ticks);