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Mastering Delphi Programming: A Complete Reference Guide
book

Mastering Delphi Programming: A Complete Reference Guide

by Primož Gabrijelčič
November 2019
Beginner to intermediate content levelBeginner to intermediate
674 pages
15h
English
Packt Publishing
Content preview from Mastering Delphi Programming: A Complete Reference Guide

Singleton

The singleton pattern was part of the original Design Patterns collection. It makes sure that a class, which we call a singleton class, has only one instance. In other words, only one object of that class may ever be created during the program's life. Such a class must also provide global access to this instance.

Let me give a real-life example to clarify this definition. You probably live in a country that allows one, and only one, president (or monarch, head of state, and so on.) to exist at the same time. So, that person is a singleton.

You will notice that the pattern tells us nothing about how that one singleton instance should be destroyed. It also doesn't specify when the singleton instance should be created.

Whenever you ...

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Publisher Resources

ISBN: 9781838989118Other