The Object Oriented Way
The Object Oriented Way
About the Book
Have you ever wondered why there are so many rules in object oriented programming?
I asked myself that question a decade ago. This book is the result of everything I’ve learned since.
I'm Christopher Okhravi (PhD), a Senior Lecturer at Uppsala University and a YouTuber with over 150,000 followers. I’ve spent the last ten years decoding OOP — so you don’t have to.
This is a practical, language-agnostic guide to OOP. It gives you mental models to reason about complexity and choose the right abstraction at the right time.
I use it in my own teaching. Now, it can be yours.
🔒 Buy Now and Unlock Private Community Access
When you buy the book, you’ll get exclusive access to a private community where you can:
- ✅ Ask questions and get feedback.
- ✅ Showcase your apps and ideas.
- ✅ Learn alongside other developers.
🥇 #1 on LeanPub. Top 10 for months.
The feedback has been overwhelming:
- "I've been coding for almost a decade, and I've never seen these concepts explained this well.”
- "This is one of the best pieces of advice.”
- "Wow! Such a clean and logical delivery!"
- "Finally, I get the concept after using it for so many years without fully understanding it."
- "No one will forget this now."
- "I name you the OOP maestro 🥂"
🧠 What You’ll Learn
Inside, you’ll learn how to think about OOP — not just memorize it.
- When to use subtypes instead of objects.
- When to choose dependency injection over instantiation.
- When to use interfaces or composition over inheritance.
- How strategies, delegates, and higher-order functions solve the same problem.
- How bridge is like a strategy within a strategy.
- How dependency injection and replacing conditionals with polymorphism lead to dependency inversion.
- How observables are like events, observers like delegates, and how they all relate to asynchronous and reactive programming.
- How iterators and enumerables relate to streams and infinite lists.
- How the visitor pattern is like pattern matching.
- How Variance is the key to the Liskov Substitution Principle and what it enables.
- And more…
🙋♂️ Frequently Asked Questions
📘 Is this too advanced for me? No. We start from the very basics. No assumptions, no jargon walls. You don’t even need to know what a class is.
🧠 Is this too simple for me? No. The book scales up. Skip the chapters you find easy. Even seasoned developers find the book enlightening.
📦 Will there be a paperback version? Possibly. If the digital version does well, a paperback could follow. Buying early helps make that happen.
⏳ Why buy before it’s complete? Because early buyers get exclusive access to a private community where you can ask questions, share your projects, and learn directly from me and other readers.
🔑 How do I join the private community? Instructions are included in the email you get after purchasing.
📅 When will the final version be done? The book is being released chapter by chapter, and updates are frequent. Your purchase includes all future updates at no cost.
About the Author
Table of Contents
- Preface
- How To Read This Book
- 1.Programming
- 1.1.Algorithms
- 1.2.Computation
- 1.3.Programs
- 1.4.Syntax
- 1.5.Compilation
- 1.6.Execution
- 1.7.Interpretation
- 1.8.Comments
- 2.Data
- 2.1.Values
- 2.2.Variables
- 2.3.Data Types
- 2.4.Constants
- 2.5.Type Checking
- 2.6.Type Inference
- 2.7.Null
- 2.8.Dynamic Types
- 3.Expressions
- 3.1.Arithmetic Operators
- 3.2.Equality Operators
- 3.3.Relational Operators
- 3.4.Logical Operators
- 3.5.String Concatenation
- 3.6.String Interpolation
- 3.7.Assignment Operator
- 3.8.Precedence
- 3.9.Associativity
- 4.Control Flow
- 4.1.Statements
- 4.2.Selection Statements
- 4.3.Selection Expressions
- 4.4.Conditionals Breed
- 4.5.Iteration Statements
- 4.6.Exceptions
- 5.Methods
- 5.1.Local Functions
- 5.2.Parameters
- 5.3.Return Values
- 5.4.Fat Arrows
- 5.5.Recursion
- 6.Type Definitions
- 6.1.Enumeration Types
- 6.2.Tuples
- 6.3.Arrays
- 6.4.References and Values
- 7.Organization
- 7.1.Namespaces
- 7.2.Entry Point
- 7.3.Global Variables Considered Harmful
- 8.Objects
- 8.1.Classes
- 8.2.Fields
- 8.3.Constructors
- 8.4.Instance Methods
- 8.5.The
thisKeyword
- 8.6.Encapsulation
- 8.7.Access Modifiers
- 8.8.Properties
- 8.9.Static
- 8.10.Overloading
- 8.11.Extension Methods
- 9.Object Composition
- 9.1.Dependency Instantiation
- 9.2.Dependency Injection
- 9.3.Tell Don’t Ask
- 9.4.Law of Demeter
- 10.Type Design
- 10.1.Primitive Obsession
- 10.2.Make Impossible States Impossible
- 10.3.Bijection
- 10.4.Throwing Exceptions
- 10.5.Fail Fast
- 11.Subtype Polymorphism
- 11.1.Substitutability
- 11.2.Interfaces
- 11.3.Run-Time Type vs Compile-Time Type
- 11.4.Dynamic Dispatch
- 11.5.Replace Conditional With Polymorphism
- 11.6.Not All Conditionals Can Be Replaced With Polymorphism
- 11.7.Don’t Use Subtypes for Data Variation
- 11.8.Multiple Interfaces
- 11.9.Interface Segregation Principle
- 12.Inheritance
- 12.1.Class Inheritance
- 12.2.Overriding
- 12.3.Hiding
- 12.4.The
baseKeyword
- 12.5.Constructor Chaining
- 12.6.Protected Access Modifier
- 12.7.Abstract Classes
- 12.8.When To Use Inheritance
- 12.9.Hierarchical Reuse
- 12.10.Interface Inheritance
- 12.11.Default Interface Methods
- 12.12.Multiple Inheritance
- 12.13.Fragile Base Class Problem
- 13.Type Conversions
- 13.1.Kinds of Type Conversions
- 13.2.Upcasting
- 13.3.Downcasting
- 13.4.Everything Is An Object
- 14.UML Class Diagrams
- 14.1.Classes
- 14.2.Fields
- 14.3.Access Modifiers
- 14.4.Properties
- 14.5.Instance Methods
- 14.6.Constructors
- 14.7.Composition
- 14.8.Interfaces
- 14.9.Inheritance
- 14.10.Abstract
- 15.More Type Definitions
- 15.1.Structure Types
- 15.2.Record Types
- 15.3.Anonymous Types
- 16.Generics
- 16.1.Can Everything Be Generic?
- 16.2.Generic Types
- 16.3.Generics Maintain Static Type Safety
- 16.4.Generic Supertypes
- 16.5.Generic Methods
- 16.6.Type Parameter Constraints
- 16.7.Collections
- 17.Composition Over Inheritance
- 17.1.The Duck Dilemma
- 17.2.Strategy Pattern
- 17.3.Bridge Pattern
- 17.4.Delegates
- 17.5.Generic Delegates
- 17.6.Multicast Delegates
- 17.7.Lambdas
- 18.Dependency Inversion
- 18.1.Depend on Abstractions, Not on Concretions
- 18.2.Dependency Inversion Principle
- 18.3.Factory Method Pattern
- 19.Observers
- 19.1.Observer Pattern
- 19.2.Events
- 19.3.Event-Driven Programming
- 19.4.Asynchronous Programming
- 19.5.Reactive Programming
- 20.Iterators
- 20.1.Iterator Pattern
- 20.2.Enumerables
- 20.3.The
yieldStatement
- 20.4.Lazy Evaluation
- 20.5.Infinite Iterators
- 20.6.LINQ
- 21.Multiple Dynamic Dispatch
- 21.1.Visitor Pattern
- 21.2.Pattern Matching
- 22.Variance
- 22.1.Type Safe Variance
- 22.2.Covariance
- 22.3.Contravariance
- 22.4.Invariance
- 22.5.The Square-Rectangle Problem
- 22.6.Liskov Substitution Principle
- 22.7.Variant Class Inheritance
- 22.8.Variant Delegates
- 22.9.Variant Generic Delegates
- 22.10.Variant Generic Interfaces
- Epilogue
- Preface
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