About the Book

Driven by Example, this Book Applies Useful Patterns of Clean Software Architecture to Mac App Development

You do some kind or other of what may be called "software architecture" anyway.

So better know the reasons for the moves you take. Own the alternatives, and design your code accordingly to gain confidence that your stuff is really working.

Learn how to …

• design reusable code,
• get a solid test harness up and running, and
• separate the components of your application. 

All this will make your application easier to change and easier to maintain. It will make you a happier developer, even when you're just exploring new parts of the Cocoa Framework.

To develop Mac applications, you'll need to know why and how to separate components. Using the latest technology and a head-start into Swift programming, this book will show you the pro's and con's of several design decisions and discuss alternative approaches so you get to know your options.

The Core Ideas of the Book

I want to share the core ideas and theses of the book with you:

• Apple's Core Data is a very invasive framework. It works best when you couple everything, beginning at the user interface, to Core Data entities. Cocoa Bindings make a lot of the magic possible, but they come at a cost: the Core Data entities (or NSManagedObject subclasses, for that matter) are bound to do a lot of different things for different "clients", wheras by 'client' I mean consuming views, background services, and the like. It'd be easier to maintain the code if you model entities for each "Bounded Context" separately.
• Adopting Domain-Driven Design thinking, small service objects are favorable. It's easy to create Data Transfor Objects in Swift using structs, for example. Core Data should be pushed outside the domain (i.e. where the business logic is hosted) and become an implementation detail.
• Once you free your app from the entanglement by Core Data (and other Apple suggested best practices which don't scale well), you will be able to leverage powerful design patterns. I created domain event wrappers around NSNotification to make event handling easier and failure-proof. Using events to propagate changes (instead of using Bindings, for example) makes concurrent programming easier.

That's part of the topics we cover in this book. Maybe you won't be a DDD expert afterwards, but so neither am I. Instead, we'll explore useful patterns to make the code manageable and to get more comfortable ever writing Mac applications which are ready to scale.

The Book is Open Source, by the way!

The book is Open Source. You can contribute on GitHub:

• Book manuscript and manuscript website
• Example project code

Just create a pull request if you came up with a better description of something, or if you want to add a useful reference, for example. Together, we can make the book a lot better.

Your feedback is much appreciated!

About the Author

Christian Tietze

@ctietze

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Christian develops the Word Counter for Mac on his own and has a few years experience creating iOS apps, too. He can move fast and deploy often thanks to clean code and solid application design.

Christian writes regularly on his own website where you may find out more about future book projects. He's also writing for Zettelkasten.de, where he and his pal Sascha are discussing theory and practice of good knowledge management.