Excuse Me! Are you my Type?

Type and sub type is an important aspect of object oriented programming. In this session we will learn about the Type and how they are used in Kotlin.

Also, we will have a look at some interesting types in Kotlin.

We will also be learning about variance and how it's applied to generic classes in Kotlin.

Transcript

1. Ashesh Bharadw aj KOTLIN TALK EXCUSE ME! ARE YOU MY TYPE?
2. CLASS & OBJECT Photo by Pez González on Unsplash Photo by S O C I A L . C U T on Unsplash
3. READ THIS STATEMENT val name: String = "Hakuna Matata"
4. WHAT IS A TYPE? val name: String = 68 via GIPHY
5. WHERE DOES THE TYPE COME FROM? class Student val x: Student Photo by Oliver Cole on Unsplash
6. NULL POINTER EXCEPTION via GIPHY
7. CONGRATULATIONS! IT’S TWINS Photo by Jens Johnsson on Unsplash class Student val x: Student val y: Student?
8. INHERITANCE [ Phone ] [ SmartPhone ] [ AndroidPhone ] IS A IS A IS A Transitive
9. SUBTYPE & SUBSTITUTION PRINCIPLE open class Person class Student: Person() val x: Student = Student() val y: Person = x
10. LISKOV SUBSTITUTION PRINCIPLE If S is a subtype of T, then objects of type T in a program may be replaced with objects of type S without altering any of the desirable properties of that program
11. A RECTANGLE IS A SQUARE
12. FEW INTERESTING TYPES via GIPHY
13. THE ONE AT THE TOP Any, supertype of all types. val name: Any = "Shyam" val age: Any = 24 Photo by asoggetti on Unsplash
14. I LIED TO YOU Any? is the supertype of Any val a: Any = 20 var b: Any? = a val x: String = "Suresh" var y: String? = x via GIPHY
15. THE TYPE HIERARCHY
16. UNIT TYPE
17. NOTHING via GIPHY
18. NOTHING
19. Nothing
20. THE UPDATED TYPE HIERARCHY
21. NULL: WHAT’S MY TYPE? val x: Nothing? = null val x = null
22. GENERICS Generics is a feature to utilize functions and properties of a class among different data type while keeping type safety in mind. class Box<T>
23. VARIANCE How subtyping between more complex types relate to subtyping between their components.
24. INVARIANT
25. INVARIANT
26. WHY INVARIANT?
27. NO POLYMORPHISM? AISE KAISE?.
28. COVARIANT
29. COVARIANT
30. CONTRAVARIANT
31. CONTRAVARIANT
32. VARIANCE SUMMARY INVARIANT COVARIANT CONTRAVARIANT
33. DID SOMEONE JUST SAY IT LOUD? via GIPHY
34. THANK YOU ASHESH BHARADWAJ linkedin.com/in/asheshb medium.com/@asheshb facebook.com/asheshb twitter.com/asheshbt