Book Image

Hands-On Design Patterns with Swift

By : Florent Vilmart, Giordano Scalzo, Sergio De Simone
Book Image

Hands-On Design Patterns with Swift

By: Florent Vilmart, Giordano Scalzo, Sergio De Simone

Overview of this book

Swift keeps gaining traction not only amongst Apple developers but also as a server-side language. This book demonstrates how to apply design patterns and best practices in real-life situations, whether that's for new or already existing projects. You’ll begin with a quick refresher on Swift, the compiler, the standard library, and the foundation, followed by the Cocoa design patterns – the ones at the core of many cocoa libraries – to follow up with the creational, structural, and behavioral patterns as defined by the GoF. You'll get acquainted with application architecture, as well as the most popular architectural design patterns, such as MVC and MVVM, and learn to use them in the context of Swift. In addition, you’ll walk through dependency injection and functional reactive programming. Special emphasis will be given to techniques to handle concurrency, including callbacks, futures and promises, and reactive programming. These techniques will help you adopt a test-driven approach to your workflow in order to use Swift Package Manager and integrate the framework into the original code base, along with Unit and UI testing. By the end of the book, you'll be able to build applications that are scalable, faster, and easier to maintain.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

The strategy pattern


To conclude this chapter, we'll cover the strategy pattern. This design pattern lets you write programs that are able to select different algorithms or strategies at runtime. For example, using the strategy pattern may help in sorting objects in different ways, by letting you specify the comparison function at runtime.

You will find yourself wanting to implement the strategy pattern when faced with:

  • Complex classes with multiple algorithms changing at runtime
  • Algorithms that may improve performance and need to be swapped at runtime
  • Multiple implementations of similar algorithms in different classes, making them difficult to extract
  • Complex algorithms that are strongly tied to data structures

The goal of the strategy pattern is to let you isolate those algorithms from the context they operate in.

Components of the strategy pattern

The strategy pattern involves only a few components:

  • Context objects, which will have a Strategy member
  • Strategy implementations that can be swapped...