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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
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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

Marker interface

The marker interface pattern has its origin in the Java world. It is used to provide metadata capabilities in a language that doesn't have explicit support for that. The marker interface concept was largely replaced with the use of attributes or a similar code annotation tool in modern languages.

In programming, metadata provides a way of adding code-describing tags to the program. Unlike normal data variables and fields, which store information required to run the program and to process user data, metadata provides data about classes (and variables and fields) themselves.

Metadata is a label attached to a product. It is a note on a car dashboard saying, "Change oil at 150.000 km," or a message on a sandwich in a communal kitchen stating, "This belongs to me!"

A marker interface pattern provides a way of adding metadata descriptions to...

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