using System;
namespace DoFactory.GangOfFour.Singleton.Structural
{
class MainApp
{
static void Main()
{
// Constructor is protected -- cannot use new
Singleton s1 = Singleton.Instance(); //this will call: instance = new Singleton();
Singleton s2 = Singleton.Instance(); //this will use the reference created above
if (s1 == s2)
{
Console.WriteLine("Objects are the same instance");
}
Console.Read();
}
}
//-----------------------------------------------------------------------
class Singleton
{
//static field
private static Singleton instance; //use static because we don't want to create instance of the class
// protected constructor
protected Singleton()
{
}
//static method
public static Singleton Instance() //use static because we don't want to create instance of the class
{
// Uses lazy initialization
if (instance == null)
{
instance = new Singleton();
}
return instance;
}
}
}
