The easiest way to learn design patterns
The easiest way to learn design patterns
With C# code samples using .NET 6 templates
About the Book
Design patters are something that you will need to get familiar with as a programmer who works with object oriented languages. And this is primarily because they represent well-defined solutions to common software development problems. So, instead of thinking through all the details of your solution, you can simply check if any of the existing design patterns can be used. You won’t have to reinvent the wheel.
The main problem with design patterns is that they are not necessarily easy to learn. Many developers, especially the ones who don’t have a lot of software-building experience, struggle with them. But if you do struggle with them, it may prevent you from getting a programming job at a reputable organization. After all, recruiting managers often ask questions about design patterns. Otherwise, not knowing design patterns will make you less effective as a software developer, which will slow down your career progress.
The main reason why design patterns are so hard to learn is because of the way they are normally taught. Usually, if you pick pretty much any book on design patterns or open pretty much any online article about them, it would provide a collection of design patterns that you would need to go through. You would then have to got through each of them, try your best to understand the principles behind it and only then try to figure out how to apply it in a real-life situation.
It's a tedious process that doesn't always bring about the right results. It's not uncommon for software developers to memorize just a handful of design patterns that they have been using in their own projects. The remaining ones have been forgotten as soon as they've been learned. And it's hard to figure out which design pattern applies in which situation if you only remember a handful of them.
This book provides a different approach. It uses a methodology that makes it easy to learn design patterns. So, you no longer have to brute-force your way through them. The process of effective learning is not about memorization. It's about associations. You learn new things easily when you can clearly see how new facts related to your existing knowledge. And this is precisely the method that this book is built around.
You won't have to brute-force your way into design patterns. In fact, you won't even start with the design patterns. First, we will go through a list of common problems that software developers are required to solve. Those are the things that every software developer can associate with. Even if you haven't faced a particular type of a problem yet, you will still be able to easily understand its description. For each of these problems, we will go through the design patterns that can solve it. And for each one of them, you will go through its core principle and the description of how it can solve this type of a problem. Only then you will be invited to examine this particular design pattern in detail, so you can understand how to implement it in your own code.
This structure of the book also makes it valuable as a reference book. Even when you don't know or don't remember design patterns, looking them up becomes easy. What you need to find is a description of the type of a problem you are trying to solve. And then you will be able to follow it to find the actual design patterns that you can apply to solve it.
Therefore this book is not only an effective learning tool. It's also a reference book that's incredibly easy to navigate. It's been structured in such a way that you'll be able to find the right answer in seconds.
Bundles that include this book
Reader Testimonials
Bella Rabbit
Great Resource!
The title says it all! This book showed me the easiest way to learn design patterns… and it did so well because the book has its own methodology. Pick it up and find out precisely what I mean. Even with familiarity on the topic, it can teach a book a two. My friend here tried it out, who has experience in the subject, and she said she found some pointers unexpectedly useful. For her, it also had many design patterns that could be used as a quick reference. It’s navigation friendly.
Table of Contents
-
Introduction
- What design patterns are
- Why would you want to learn design patterns
- Why design patterns are hard to learn
- The goal of this book
- The structure of this book
-
About the author and his mission
- Getting in touch
- Helping to spread the word
- Part 1: SOLID principles and why they are important
-
1. Single responsibility principle
- What is single responsibility principle
- The importance of single responsibility principle
- The concept of class cohesion
- Conclusion
-
2. Open-closed principle
- What is open-closed principle
- Implementing the open-closed principle in C#
- Conclusion
-
3. Liskov substitution principle
- Implementing Liskov substitution principle in C#
- Conclusion
-
4. Interface segregation principle
- What is interface segregation principle
- Importance of interface segregation
- When NotImplementedException is appropriate
-
5. Dependency inversion principle
- What is dependency inversion principle
- Why dependency inversion principle is important
- Dependency inversion is not only useful in unit tests
- Part 2: The problems that design patterns are intended to solve
-
6. Not knowing what object implementations you’ll need ahead of time
- Suitable design patterns
-
7. Making several exact copies of a complex object
- Suitable design patterns
-
8. Using many instances of an object while keeping code running smoothly
- Suitable design patterns
-
9. Using the same single instance of an object throughout the application
- Suitable design patterns
-
10. Third party components aren’t directly compatible with your code
- Suitable design patterns
-
11. Adding new functionality to existing objects that cannot be modified
- Suitable design patterns
-
12. Accessing complex back-end logic from the presentation layer
- Suitable design patterns
-
13. User interface and business logic are developed separately
- Suitable design patterns
-
14. Building a complex object hierarchy
- Suitable design patterns
-
15. Implementing complex conditional logic
- Suitable design patterns
-
16. Multiple object instances of different types need to be able to communicate with each other
- Suitable design patterns
-
17. Multiple stages of processing are needed
- Suitable design patterns
-
18. The system is controlled by complex combinations of inputs
- Suitable design patterns
-
19. Ability to undo an action that has been applied
- Suitable design patterns
-
20. Ability to traverse a collection without knowing its underlying structure
- Suitable design patterns
-
21. Creating a family of related algorithms
- Suitable design patterns
- 22. Summary of the problems design patterns are intended to solve
- Part 3: Design patterns demonstrated in C#
- 23. Design pattern categories
- Creational design patterns
-
24. Factory Method
- Prerequisites
- Factory Method implementation example
- Benefits of using Factory Method
- Caveats of using Factory Method
-
25. Abstract Factory
- Prerequisites
- Abstract Factory implementation example
- Benefits of using Abstract Factory
- Caveats of using Abstract Factory
-
26. Builder
- Prerequisites
- Builder implementation example
- Benefits of using Builder
- Caveats of using Builder
-
27. Prototype
- Prerequisites
- Prototype implementation example
- Benefits of using Prototype
- Caveats of using Prototype
-
28. Singleton
- Prerequisites
- Singleton implementation example
- Benefits of using Singleton
- Caveats of using Singleton
- Structural design patterns
-
29. Adapter
- Prerequisites
- Adapter implementation example
- Benefits of using Adapter
- Caveats of using Adapter
-
30. Bridge
- Prerequisites
- Bridge implementation example
- Benefits of using Bridge
- Caveats of using Bridge
-
31. Composite
- Prerequisites
- Composite implementation example
- Benefits of using Composite
- Caveats of using Composite
-
32. Decorator
- Prerequisites
- Decorator implementation example
- Benefits of using Decorator
- Caveats of using Composite
-
33. Facade
- Prerequisites
- Facade implementation example
- Benefits of using Facade
- Caveats of using Facade
-
34. Flyweight
- Prerequisites
- Flyweight implementation example
- Benefits of using Flyweight
- Caveats of using Flyweight
-
35. Proxy
- Prerequisites
- Proxy implementation example
- Benefits of using Proxy
- Caveats of using Proxy
- Behavioral design patterns
-
37. Command
- Prerequisites
- Command implementation example
- Benefits of using Command
- Caveats of using Command
-
36. Chain of Responsibility
- Prerequisites
- Chain of Responsibility implementation example
- Benefits of using Chain of Responsibility
- Caveats of using Chain of Responsibility
-
38. Iterator
- Prerequisites
- Iterator implementation example
- Benefits of using Iterator
- Caveats of using Iterator
-
39. Mediator
- Prerequisites
- Mediator implementation example
- Benefits of using Mediator
- Caveats of using Mediator
-
40. Memento
- Prerequisites
- Memento implementation example
- Benefits of using Memento
- Caveats of using Memento
-
41. Observer
- Prerequisites
- Observer implementation example
- Benefits of using Observer
- Caveats of using Observer
-
42. State
- Prerequisites
- State implementation example
- Benefits of using State
- Caveats of using State
-
43. Strategy
- Prerequisites
- Strategy implementation example
- Benefits of using Strategy
- Caveats of using Strategy
-
44. Template Method
- Prerequisites
- Template Method implementation example
- Benefits of using Template Method
- Caveats of using Template Method
-
45. Visitor
- Prerequisites
- Visitor implementation example
- Benefits of using Visitor
- Caveats of using Visitor
- Epilogue
The Leanpub 60-day 100% Happiness Guarantee
Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
Do Well. Do Good.
Authors have earned$11,600,486writing, publishing and selling on Leanpub, earning 80% royalties while saving up to 25 million pounds of CO2 and up to 46,000 trees.
Learn more about writing on Leanpub
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers), EPUB (for phones and tablets) and MOBI (for Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
Top Books
C++20 - The Complete Guide
Nicolai M. JosuttisAll new language and library features of C++20 (for those who know previous C++ versions).
The book presents all new language and library features of C++20. Learn how this impacts day-to-day programming, to benefit in practice, to combine new features, and to avoid all new traps.
Buy early, pay less, free updates.
Other books:
Cronache di Domain-Driven Design
Francesco Strazzullo, Matteo Baglini, Gianluca Padovani, Emanuele DelBono, Marco Consolaro, Alessandro Colla, Uberto Barbini, Alberto Acerbis, Julie Camosseto, DDD Open, and Alberto BrandoliniCronache di Domain-Driven Design: un libro corale in italiano fatto di storie indipendenti tra loro, che sono il risultato dell’applicazione di Domain-Driven Design su progetti reali.
Ansible for DevOps
Jeff GeerlingAnsible is a simple, but powerful, server and configuration management tool. Learn to use Ansible effectively, whether you manage one server—or thousands.
Jetpack Compose internals
Jorge CastilloJetpack Compose is the future of Android UI. Master how it works internally and become a more efficient developer with it. You'll also find it valuable if you are not an Android dev. This book provides all the details to understand how the Compose compiler & runtime work, and how to create a client library using them.
OpenIntro Statistics
David Diez, Christopher Barr, Mine Cetinkaya-Rundel, and OpenIntroA complete foundation for Statistics, also serving as a foundation for Data Science.
Leanpub revenue supports OpenIntro (US-based nonprofit) so we can provide free desk copies to teachers interested in using OpenIntro Statistics in the classroom and expand the project to support free textbooks in other subjects.
More resources: openintro.org.
R Programming for Data Science
Roger D. PengThis book brings the fundamentals of R programming to you, using the same material developed as part of the industry-leading Johns Hopkins Data Science Specialization. The skills taught in this book will lay the foundation for you to begin your journey learning data science. Printed copies of this book are available through Lulu.
Functional event-driven architecture: Powered by Scala 3
Gabriel VolpeExplore the event-driven architecture (EDA) in a purely functional way, mainly powered by Fs2 streams in Scala 3!
Leverage your functional programming skills by designing and writing stateless microservices that scale, powered by stateful message brokers.
Mastering STM32 - Second Edition
Carmine NovielloWith more than 1200 microcontrollers, STM32 is probably the most complete ARM Cortex-M platform on the market. This book aims to be the first guide around that introduces the reader to this exciting MCU portfolio from ST Microelectronics and its official CubeHAL and STM32CubeIDE development environment.
CCIE Service Provider Version 4 Written and Lab Exam Comprehensive Guide
Nicholas RussoThe service provider landscape has changed rapidly over the past several years. Networking vendors are continuing to propose new standards, techniques, and procedures for overcoming new challenges while concurrently reducing costs and delivering new services. Cisco has recently updated the CCIE Service Provider track to reflect these changes; this book represents the author's personal journey in achieving that certification.
CCIE SP v5.0
Łukasz Bromirski, Piotr Jablonski, and Nicholas RussoAre you striving to prepare to and pass CCIE SP lab exam? Take the opportunity and get this workbook! With the attached initial cfg files you will prepare yourself for the CCIE SP exam as well as learn SP technologies applicable to all kinds of today modern networks! This workbook covers blueprint topics and provides challenging examples.
Top Bundles
- #1
Software Architecture for Developers: Volumes 1 & 2 - Technical leadership and communication
2 Books
"Software Architecture for Developers" is a practical and pragmatic guide to modern, lightweight software architecture, specifically aimed at developers. You'll learn:The essence of software architecture.Why the software architecture role should include coding, coaching and collaboration.The things that you really need to think about before... - #2
Practical FP in Scala + Functional event-driven architecture
2 Books
Practical FP in Scala (A hands-on approach) & Functional event-driven architecture, aka FEDA, (Powered by Scala 3), together as a bundle! The content of PFP in Scala is a requirement to understand FEDA so why not take advantage of this bundle!? - #3
All the Books of The Medical Futurist
6 Books
We put together the most popular books from The Medical Futurist to provide a clear picture about the major trends shaping the future of medicine and healthcare. Digital health technologies, artificial intelligence, the future of 20 medical specialties, big pharma, data privacy, digital health investments and how technology giants such as Amazon... - #4
CCIE Service Provider Ultimate Study Bundle
2 Books
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification... - #6
Pattern-Oriented Memory Forensics and Malware Detection
2 Books
This training bundle for security engineers and researchers, malware and memory forensics analysts includes two accelerated training courses for Windows memory dump analysis using WinDbg. It is also useful for technical support and escalation engineers who analyze memory dumps from complex software environments and need to check for possible... - #7
Modern C++ Collection
3 Books
Get All about Modern C++C++ Standard Library, including C++20Concurrency with Modern C++, including C++20C++20Each book has about 200 complete code examples. Updates are included. When I update one of the books, you immediately get the updated bundle. You can expect significant updates to each new C++ standard (C++23, C++26, .. ) and also... - #9
Retromat eBook Bundle for Agile Retrospectives
2 Books
If you facilitate retrospectives this bundle is for you: "Plans for Retrospectives" helps beginners learn the lay of the land with tried-and-true plans. Once you know your way around, "Run great agile retrospectives" contains all 135+ activities in Retromat for you to mix and match.