Singleton Pattern

This is a very popular creational pattern which restricts a class to have only one instance.

Example: "Prime Minister of India" is a singleton pattern as he/she has unique responsibilities and attributes.

Implementation: A singleton class can't have a public constructor and it has to be sealed. The entry point to get the singleton instance would be a static method or a static property.






public sealed class PrimeMinister
{
private static PrimeMinister instance = new PrimeMinister(); 

private PrimeMinister(){ } 

public static PrimeMinister Instance
{
get { return instance; }
}
}



Thread safe

public sealed class Singletone
{
private static Singletone instance=null;
//constructor
private Singletone(){ }
Object objlock=new Object();
public static Singletone Instance
{
        get {
              if(instance==null)
                {
                  Lock(objlock)

         {

                       if(instance==null)

   {

          Instance=NEW Singletone();

   }

         }

         
              }

        return instance; 
       }
}

}