Singleton Pattern in C#

The Singleton pattern ensures a class has only one instance and provides a global point of access to it. This is useful when exactly one object is needed to coordinate actions across the system. Just for fun try to use an anime reference to the Singleton Pattern. Imagine the Singleton pattern as Kurama, the Nine-Tails beast sealed within Naruto. Kurama is a unique entity with only one Kurama throughout the entire Naruto series. Naruto (the system) has a single instance of Kurama that he can access when needed. Here's how this relates to the Singleton pattern:

• Single Instance: Kurama is the only Nine-Tails beast.

• Global Access Point: Naruto can access Kurama's power whenever he needs it.

  
  

This how Kurama lives inside of Naruto.

public class Kurama

{

    // Lazy<T> is used to ensure the instance is created only when needed, and it's thread-safe.

    private static readonly Lazy<Kurama> _instance = new Lazy<Kurama>(() => new Kurama());

    // Private constructor to prevent instantiation from outside

    private Kurama()

    {

        // Initialize Kurama's power or state here

    }

    // Public method to provide a global access point

    public static Kurama Instance

    {

        get

        {

            return _instance.Value;

        }

    }

    // Example method to use Kurama's power

    public void UseKuramaPower()

    {

        Console.WriteLine("Using Kurama's power!");

    }

}

• Lazy<T>: The Lazy<T> type ensures that the Kurama instance is created only when the Instance property is accessed for the first time. It also ensures thread safety.

• Static Readonly Field: The _instance field is static and readonly, ensuring that there is only one instance of Kurama, and it’s created lazily.

• Private Constructor: The constructor remains private to prevent instantiation from outside the class.

• Instance Property: The Instance property returns the value of _instance.Value, which triggers the creation of the instance if it hasn’t been created yet.

This   Naruto may use Kurama’s power on his ninja missions.

class Program

{

    static void Main(string[] args)

    {

        // Access the single instance of Kurama

        Kurama kurama = Kurama.Instance;

        

        // Use Kurama's power

        kurama.UseKuramaPower();

    }

}

In this example, the instance of Kurama is created only when Kurama.The instance is accessed for the first time. This ensures efficient resource usage, and the thread safety provided by Lazy<T> ensures that the Singleton pattern is correctly implemented in a multithreaded environment. By using Lazy<T>, you get both lazy initialization and thread safety cleanly and efficiently, making it a robust approach for implementing the Singleton pattern in C#.

Another example for using Singleton pattern Configuration Settings, Logging, Database Connection Pooling, Thread Pool, or Caching.

Singleton pattern can be applied to various practical scenarios where a single instance is necessary to maintain consistency, manage resources efficiently, and provide a global point of access. While the Singleton pattern can be useful in certain scenarios, it's important to consider these disadvantages and use it judiciously. In many cases, alternative design patterns such as dependency injection or factory patterns might be more appropriate and provide greater flexibility and testability.

I hope that you got some out of this article. I hope that put this in development jutsu on you coding missions.

Keep Coding,

BK