CSC/ECE 517 Fall 2010/ch3 3f DF

The Singleton pattern in static and dynamic languages

Introduction

Text overview

UML Diagram

Static Language Implementation

class MySingleton
{
	public:
		static MySingleton* Instance()
		{
			if(s_pSingletonObject == NULL)
				s_pSingletonObject = new MySingleton;
				
			return s_pSingletonObject;
		}
		
		static void Destroy()
		{
			if(s_pSingletonObject != NULL)
			{
				delete s_pSingletonObject;
				s_pSingletonObject = NULL;
			}
		}
		
	private:
		//Direct access to the constructor/destructor is prohibited
		MySingleton() {}
		virtual ~MySingleton() {}
		
		static MySingleton* s_pSingletonObject;
};

Dynamic Language Implementation

Ruby Sample code here