Coroutine to the rescue! Adi Polak

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

No content

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 :

Kotlin coroutines

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 ?

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

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

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

HOW? SUSPENDIND FUNCTIONS CHANNELS BUILDERS CONTEXT AND SCOPE @AdiPolak

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

Job Dispatcher COROUTINES CONTEXT AND SCOPE @AdiPolak Dispatchers.Default Dispatchers.Main Dispatchers.IO Dispatchers.Unconfined fun CoroutineScope.launch( context: CoroutineContext = EmptyCoroutineContext, ..): Job coroutineContext[Job]

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

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

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].

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

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

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

Questions