Efficient Async Coding in Kotlin Coroutines - BoJUG

Presented at BoJUG, January 2019 conference, this presentation walks you through the basics of Coroutines and guides you in implementing them in your project.

Transcript

1. Rivu Chakraborty Efficient Async Coding in Kotlin Coroutines 1 Bangalore JAVA User Group (BoJUG) - Year’s First Meetup - Full Day - Informatica - Jan, 19, 2019 19/01/19
2. Rivu Chakraborty BYJU’S @rivuchakraborty Efficient Async Coding in Kotlin Coroutines 2
3. Rivu Chakraborty BYJU’S @rivuchakraborty About Me • Sr Software Engineer (Android) - BYJU’S • Instructor - Caster.io • Google Certified Associate Android Developer • DroidJam Speaker • Author - Reactive Programming in Kotlin • Author - Functional Kotlin • Author - Coroutines for Android Developers (WIP)
4. @rivuchakraborty
5. Books https://www.packtpub.com/application-de velopment/reactive-programming-kotlin https://www.packtpub.com/application-dev elopment/functional-kotlin https://leanpub.com/coroutines-for-androi d-developers Work in Progress
6. Efficient Async Coding in Kotlin Coroutines Async => Concurrency
7. Concurrency • Ability to execute multiple code blocks at the same time @rivuchakraborty
8. Concurrency • Ability to execute multiple code blocks at the same time • Not only for Android Developers @rivuchakraborty
9. Concurrency • Ability to execute multiple code blocks at the same time • Not only for Android Developers • JavaScript - Promise • JVM, Android - Threads @rivuchakraborty
10. 10 Concurrency in Android and/or JVM • AsyncTask (Android only) • CompletableFuture (Android - API 24+, JVM 1.8) • Runnable / Thread (Custom Threadpool) • Rx • Counting... @rivuchakraborty
11. 11 Concurrency in Android • Runnable / Thread @rivuchakraborty
12. 12 Concurrency in Android • Rx @rivuchakraborty
13. 13 Concurrency in Android • Rx @rivuchakraborty If you’re using Rx only for concurrency, sorry pal, you’re doing it wrong.
14. 14 • Coroutines @rivuchakraborty Let’s you write non-blocking asynchronous code in your choice of Style - Sequentially, in Functional Style or whatever you prefer.
15. 15 • Coroutines @rivuchakraborty Let’s you write non-blocking asynchronous code in your choice of Style - Sequentially, in Functional Style or whatever you prefer. A Language level feature, managed by the Kotlin team itself.
16. 16 • Coroutines @rivuchakraborty • Let’s you write non-blocking asynchronous code in your choice of Style - Sequentially, in Functional Style or whatever you prefer. • A Language level feature, managed by the Kotlin team itself. You can add Coroutines dependency to your Kotlin project by following the instructions in GitHub ReadMe - https://github.com/kotlin/kotlinx.coroutines/blob/master/README.md#u sing-in-your-projects
17. Coroutines 17 @rivuchakraborty Light-Weight Threads Thread 1 Thread 2 Thread 3 Coroutine 1 Coroutine 2 Coroutine 3 With Coroutines, Threads are still used (for JVM).
18. Coroutines 18 @rivuchakraborty Light-Weight Threads Thread 1 Thread 2 Thread 3 Coroutine 1 Coroutine 2 C 3 C 4 C 5 C 6 C 7 C 8 C N But a single Thread can run multiple coroutines.
19. Coroutines 19 @rivuchakraborty Easy to Use
20. Suspension & Continuation Builders Suspending Functions End Coroutines Components Scope & Dispatchers @rivuchakraborty
21. Coroutines 21 @rivuchakraborty Suspending vs Blocking
22. Coroutines 22 @rivuchakraborty Suspending vs Blocking
23. Coroutines 23 @rivuchakraborty Suspending vs Blocking
24. Coroutines 24 @rivuchakraborty Suspending vs Blocking
25. Launch a Coroutine 25 @rivuchakraborty
26. Get the Job done or cancel it, your choice. :) 26 @rivuchakraborty
27. Compute Async(hrounously) 27 @rivuchakraborty
28. Deferred 28 @rivuchakraborty • Deferred Extends Job • Wrapper around your data
29. Suspending Function 29 @rivuchakraborty • suspend is a Keyword in Kotlin
30. Suspending Function 30 @rivuchakraborty • suspend is a Keyword in Kotlin • Compiler level restriction - can’t call suspend function outside CoroutineScope
31. Suspending Function 31 @rivuchakraborty • suspend is a Keyword in Kotlin • Compiler level restriction - can’t call suspend function outside CoroutineScope • Suspends execution of current coroutine
32. Coroutine Scope 32 @rivuchakraborty • Container of CoroutineContext
33. Coroutine Scope 33 @rivuchakraborty • Container of CoroutineContext • Every Coroutine Builder is an extension over CoroutineScope, and thus inherits its CoroutineContext
34. Coroutine Scope 34 @rivuchakraborty • Container of CoroutineContext • Every Coroutine Builder is an extension over CoroutineScope, and thus inherits its CoroutineContext • All Coroutines must be launched within a CoroutineScope
35. Coroutine Scope 35 @rivuchakraborty
36. Dispatchers 36 @rivuchakraborty • Determines which Thread / ThreadPool, the coroutine will run on. • Similar to the Rx Schedulers
37. Let’s Build for Android
38. Repository 38 @rivuchakraborty
39. API (Retrofit) 39 @rivuchakraborty
40. Activity 40 @rivuchakraborty
41. Call it 41 @rivuchakraborty
42. Handle Exception (Gracefully) :) 42 @rivuchakraborty
43. Rivu Chakraborty @rivuchakraborty Resources https://caster.io/courses/kotlin-coroutines-fundamental s • http://bit.ly/CodeLabCoroutines (Codelab) • http://bit.ly/CoroutinesAndroid (Article) • http://bit.ly/DroidCoroutines (Book, yet to be published) • http://bit.ly/CoroutinesGuide (Official Guide) • https://www.meetup.com/BlrKotlin/ (Bangalore Kotlin User Group) 43
44. Rivu Chakraborty @rivuchakraborty Thank you! 44