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Kotlin Coroutine to the rescue!

Kotlin Coroutine to the rescue!

Asynchronous or non-blocking programming is the new reality. Whether we're creating server-side, desktop or mobile applications, using microservices architecture or not, it provides an experience that is not only fluid from the user's perspective, but scalable when needed. Coroutines is a new feature that was released in Kotlin 1.3 and has similar counterparts in other languages like C# and JavaScript. Let’s understand together what it is all about.


adi polak

May 15, 2019


  1. Coroutine to the rescue! Adi Polak

  2. About me – Adi Polak @adipolak https://medium.com/@adipolak https://dev.to/adipolak

  3. None
  4. Kotlin: 1. Developed by JetBrains (IntelliJ authors) 2. Powers all

    JetBrains tools 3. Open source 4. 100% interoperable with Java 5. First language on Android 6. Provides: a. Null safety b. Higher order function c. Data classes d. Extension functions e. Since Kotlin 1.1 – coroutines f. … MORE! @AdiPolak L E T ’ S S TA R T F R O M T H E B E G I N N I N G :
  5. Kotlin coroutines

  6. C o r o u t i n e s

    c o m m o n u s e c a s e s • Asynchronous • Non blocking @AdiPolak • Server side - microservices • Android app development • … W h y ?
  7. C a n w e c o m p a

    r e c o r o u t i n e a n d t h r e a d s ? @AdiPolak
  8. CPU CORE 1 Thread 1 Thread 2 Thread 3 CONCURENCY

    IN THREADS CPU CORE 2 Thread 1 Thread 2 Thread 3 @AdiPolak
  9. Kotlin runtime Coroutine 1 Coroutine 2 Coroutine 3 CONCURENCY IN

    COROUTINES Coroutine 1 Coroutine 3 @AdiPolak

  11. suspend fun someBackgroundTask(param: List<String>): Int { // long running operation

    return 7 } fun someBackgrounTask(param: List<String>, callback: Continuation<Int>): Int { // long running operation return 7 } SUSPENDING FUNCTIONS @AdiPolak
  12. Job Dispatcher COROUTINES CONTEXT AND SCOPE @AdiPolak Dispatchers.Default Dispatchers.Main Dispatchers.IO

    Dispatchers.Unconfined fun CoroutineScope.launch( context: CoroutineContext = EmptyCoroutineContext, ..): Job coroutineContext[Job]
  13. BUILDERS @AdiPolak Extending scope functions: Launch Async Can be used

    from Main thread: runBlocking
  14. COROUTINES CONTEXT, SCOPE AND BUILDERS @AdiPolak coroutineScope { launch(Dispatchers.Default +

    CoroutineName(”some name")) { doSuspendedTask() } }
  15. CHANNELS @AdiPolak val channel1 = Channel<Any>(capacity = Channel.RENDEZVOUS) val channel2

    = Channel< Any >(capacity = Channel.CONFLATED) val channel3 = Channel< Any >(capacity = 10) val channel4 = Channel< Any >(capacity = Channel.UNLIMITED) https://proandroiddev.com/kotlin-coroutines-channels-csp-android-db441400965f Channel is a non-blocking primitive for communication between sender using [SendChannel] and receiver using [ReceiveChannel].
  16. Demo https://github.com/adipola/kotlin-coroutine-transaction-process-mock

  17. • Ktor • Vert.x • Arrow • … @AdiPolak Frameworks

  18. Summary • What and why coroutines are important • Coroutine

    and threads • Key concepts • Demo • Frameworks @AdiPolak
  19. Questions