Kotlin Essentials
Kotlin Essentials
About the Book
Kotlin is a powerful language, largely thanks to its expressive syntax, intuitive and null-safe type system, and great tooling support. In this book, we cover the essentials of Kotlin, so you can start developing with this amazing programming language. We show nearly everything you need to know in clear and executable code examples.
If you are interested in paperback, you can purchase it here.
About the Author
Bundles that include this book
Table of Contents
-
-
Introduction
- For whom is this book written?
- What will be covered?
- The Kotlin for Developers series
- My story
- Conventions
- Code conventions
- Acknowledgments
-
What is Kotlin?
- Kotlin platforms
- The Kotlin IDE
- Where do we use Kotlin?
-
Your first program in Kotlin
- Live templates
- What is under the hood on JVM?
- Summary
- Variables
-
Basic types, their literals and operations
- Numbers
- Booleans
- Characters
- Strings
- Summary
-
Conditional statements: if, when, try, and while
- if-statement
- when-statement
- when-statement with a value
- is check
- Explicit casting
- Smart-casting
- While and do-while statements
- Summary
-
Functions
- Single-expression functions
- Functions on all levels
- Parameters and arguments
-
Unitreturn type - Vararg parameters
- Named parameter syntax and default arguments
- Function overloading
- Infix syntax
- Function formatting
- Summary
-
The power of the for-loop
- Ranges
- Break and continue
- Use cases
- Summary
-
Nullability
- Safe calls
- Not-null assertion
- Smart-casting
- The Elvis operator
- Extensions on nullable types
-
nullis our friend - lateinit
- Summary
-
Classes
- Member functions
- Properties
- Constructors
- Classes representing data in Kotlin and Java
- Inner classes
- Summary
-
Inheritance
- Overriding elements
- Parents with non-empty constructors
- Super call
- Abstract class
- Interfaces
- Visibility
-
Any - Summary
-
Data classes
- Transforming to a string
- Objects equality
- Hash code
- Copying objects
- Destructuring
- When and how should we use destructuring?
- Data class limitations
- Prefer data classes instead of tuples
- Summary
-
Objects
- Object expressions
- Object declaration
- Companion objects
- Data object declarations
- Constant values
- Summary
-
Exceptions
- Throwing exceptions
- Defining exceptions
- Catching exceptions
- A try-catch block used as an expression
- The finally block
- Important exceptions
- The hierarchy of exceptions
- Summary
-
Enum classes
- Data in enum values
- Enum classes with custom methods
- Summary
-
Sealed classes and interfaces
-
Sealed classes and
whenexpressions - Sealed vs enum
- Use cases
- Summary
-
Sealed classes and
-
Annotation classes
- Meta-annotations
- Annotating the primary constructor
- List literals
- Summary
-
Extensions
- Extension functions under the hood
- Extension properties
- Extensions vs members
- Extension functions on object declarations
- Member extension functions
- Use cases
- Summary
-
Collections
- The hierarchy of interfaces
- Mutable vs read-only types
- Creating collections
- Lists
- Sets
- Maps
- Using arrays in practice
- Summary
-
Operator overloading
- An example of operator overloading
- Arithmetic operators
- The rangeUntil operator
-
The
inoperator - The iterator operator
- The equality and inequality operators
- Comparison operators
- The indexed access operator
- Augmented assignments
- Unary prefix operators
- Increment and decrement
- The invoke operator
- Precedence
- Summary
-
The beauty of Kotlin’s type system
- What is a type?
- Why do we have types?
- The relation between classes and types
- Class vs type in practice
- The relationship between types
- The subtype of all the types: Nothing
- The result type from return and throw
- When is some code not reachable?
- The type of null
- Summary
-
Generics
- Generic functions
- Generic classes
- Generic classes and nullability
- Generic interfaces
- Type parameters and inheritance
- Type erasure
- Generic constraints
- Star projection
- Summary
- Final words
-
Introduction
- Notes
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