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.

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1. Coroutine to the rescue! Adi Polak
   

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

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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 :
   

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5. Kotlin
   coroutines
   

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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 ?
   

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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
   

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8. CPU CORE 1
   Thread 1 Thread 2 Thread 3
   CONCURENCY IN THREADS
   CPU CORE 2
   Thread 1 Thread 2 Thread 3
   @AdiPolak
   

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9. Kotlin runtime
   Coroutine 1 Coroutine 2 Coroutine 3
   CONCURENCY IN COROUTINES
   Coroutine 1 Coroutine 3
   @AdiPolak
   

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10. HOW?
    SUSPENDIND
    FUNCTIONS
    CHANNELS
    BUILDERS
    CONTEXT AND SCOPE
    @AdiPolak
    

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11. suspend fun someBackgroundTask(param: List): Int {
    // long running operation
    return 7
    }
    fun someBackgrounTask(param: List, callback: Continuation): Int {
    // long running operation
    return 7
    }
    SUSPENDING FUNCTIONS
    @AdiPolak
    

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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]
    

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13. BUILDERS
    @AdiPolak
    Extending scope functions:
    Launch
    Async
    Can be used from Main thread:
    runBlocking
    

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14. COROUTINES CONTEXT, SCOPE AND BUILDERS
    @AdiPolak
    coroutineScope {
    launch(Dispatchers.Default +
    CoroutineName(”some name")) {
    doSuspendedTask()
    }
    }
    

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15. CHANNELS
    @AdiPolak
    val channel1 = Channel(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].
    

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16. Demo
    https://github.com/adipola/kotlin-coroutine-transaction-process-mock
    

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

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18. Summary
    • What and why coroutines are important
    • Coroutine and threads
    • Key concepts
    • Demo
    • Frameworks
    @AdiPolak
    

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19. Questions
    

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