This chapter covers the Singleton pattern.
GoF Definition
Ensure a class has only one instance, and provide a global point of access to it.
Concept
Let’s assume that you have a class called A, and you need to create an object from it. Normally, what would you do? You could simply use this line of code: A obA=new A();
But let’s take a closer look. If you use the new keyword ten more times, you’ll have ten more objects, right? But in a real-world scenario, unnecessary object creation is a big concern (particularly when constructor calls are truly expensive), so you need to restrict ...
