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Hands-On Design Patterns with Delphi

You're reading from   Hands-On Design Patterns with Delphi Build applications using idiomatic, extensible, and concurrent design patterns in Delphi

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Product type Paperback
Published in Feb 2019
Publisher Packt
ISBN-13 9781789343243
Length 476 pages
Edition 1st Edition
Languages
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Author (1):
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Primož Gabrijelčič Primož Gabrijelčič
Author Profile Icon Primož Gabrijelčič
Primož Gabrijelčič
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Toc

Table of Contents (19) Chapters Close

Preface 1. Section 1: Design Pattern Essentials FREE CHAPTER
2. Introduction to patterns 3. Section 2: Creational Patterns
4. Singleton, Dependency Injection, Lazy Initialization, and Object Pool 5. Factory Method, Abstract Factory, Prototype, and Builder 6. Section 3: Structural Patterns
7. Composite, Flyweight, Marker Interface, and Bridge 8. Adapter, Proxy, Decorator, and Facade 9. Section 4: Behavioral Patterns
10. Nullable Value, Template Method, Command, and State 11. Iterator, Visitor, Observer, and Memento 12. Section 5: Concurrency Patterns
13. Locking patterns 14. Thread pool, Messaging, Future and Pipeline 15. Section 6: Miscellaneous Patterns
16. Designing Delphi Programs 17. Other Kinds of Patterns 18. Other Books You May Enjoy

Singleton, Dependency Injection, Lazy Initialization, and Object Pool

In Object-Oriented Programming (OOP), everything starts with an object, and if we want to use one, we have to create it first. In most cases, that simply means calling TSomeClass.Create, but in a more complex scenario, a specialized design pattern that creates an object for us can be quite handy.

In this chapter, we'll look into four patterns from the creational group. At the end of the chapter, you'll know the following:

  • A singleton pattern, which makes sure that a class has only one instance
  • A dependency injection pattern, which makes program architecture more flexible and suitable for test-driven development
  • A lazy initialization pattern, which makes sure that we don't spend time and resources creating objects that we don't really need
  • An object pool pattern, which speeds up the creation...
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