Scala Functional Programming Patterns

Chapter 2. Singletons, Factories, and Builders

It may sound funny—and I may be stating the obvious—but everyone needs to be born at some point. Go ahead and have a good laugh at that. It is that obvious. Objects, too, need to be born at some point to do useful work. Objects have a lifetime as well. An object is constructed—and hopefully it does something useful before it eventually dies.

In Java we can see the object such as:

           Point p = new Point(23, 94);

We know what is going on—an object of class point is created; its constructor-invoked p is a reference to this newly created object.

At times, we want explicit control of the object-creation process. There are times when we want to allow creation of only one instance of a class. Creational design ...