but generics don’t real on the JVM and I don’t think there’s any sane way of genericizing ctor calls like that

well for now i solved it in a ugly way:

inline fun <reified T> saveConfig(config: T = T::class.java.constructors.find { it.parameterCount == 0 }!!.newInstance() as T) {

seems like this also works:

(T::class.java::newInstance)()

looks really dirty for me. I would use explicit factory param instead

well the intend is to use this only for classes that have a noarg constructor

Which is doesn’t look as a good solution imo. You do now runtime check and limit implementation details

well this is using java library.. jankson.. that takes a POJO or kotlin class and constructs it fro ma config file.. but it can only do that given a no-arg constructor

i am just extending it to be a bit more kotlin friendly

is there a dedicated channel for kotlinx.immutable.collections i havn't found yet?

Does anyone know if network caching is working for ktor ios HttpClient. We would like to use Kotlin Multiplatform for our network layer in an existing app targeted at Android and ios, but it seems that network responses are not being cached for ios. There was a closed issue: https://github.com/ktorio/ktor/issues/992, but the fix doesn't seem to be in latest code. This is an absolute blocker for us as we have millions of users and make many calls to a rest api that need to honour cache control headers. If this is not working, is there a plan to fix it soon as I can't see how ktor can be used in production without caching.

https://twitter.com/kotlin/status/1281249387528806402 There are some hidden gems in the Kotlin standard library that can help with string manipulation. Functions such as removePrefix(), removeSuffix(), and the shorthand for both, removeSurrounding(), can come in quite handy in the right situation: https://t.co/iIEv0GBMCm Twitter

Hello, Is there a TTL hash map data structure equivalent to guava CacheLoader for kotlin?

Found out that Kotlin fails to correctly infer type arguments in a rather simple situation if you switch from using 2 argument function to extension function. Reported as an issue: https://youtrack.jetbrains.com/issue/KT-40220 If anyone's interested, please vote for visibility. Or maybe you'll suggest a workaround, would be great! This is my second inference related bug, the first one got lost it seems, I hope this one won't. I want to make a library with a nice API, this gets in a way 🙂

Hello guys, I was following the guide linked below for write an AWS lambda with Kotlin, I opened the project with IntelliJ, added the following deps

// Coroutines
val coroutinesVersion = "1.3.7"
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$coroutinesVersion")

// Ktor Client
val ktorVersion = "1.3.2"
implementation("io.ktor:ktor-client-core:$ktorVersion")
implementation("io.ktor:ktor-client-apache:$ktorVersion")
implementation("io.ktor:ktor-client-serialization-jvm:$ktorVersion")

Wrote a very simple GET function an tried to run. but I got:

Error running 'AppKt': '1.8' is bad configured

I also see in the IDE

cannot access <http://java.io|java.io>.Closeable. which is supertype...

on

get

of

client.get<String>

Tests are running fine 😕 https://www.raywenderlich.com/5777183-write-an-aws-lambda-function-with-kotlin-and-micronaut TL;DR

gradle init
- application
- Kotlin

image.png

i use the playground to check stuff like this all the time: https://pl.kotl.in/kb8X-Bgan

Hey, was hoping to play around with reflection in the online playground, https://pl.kotl.in/7Si4InYjh, but I'm getting an error: Exception in thread "main" kotlin.jvm.KotlinReflectionNotSupportedError: Kotlin reflection implementation is not found at runtime. Make sure you have kotlin-reflect.jar in the classpath Can this be made to work in the online playground?

Can we use library written with Kotlin 1.4 (M3 for example) in an app that uses Kotlin 1.3.72? 🤔

Hi, what is the best approach of emulating

ReplaySubject

with time buffer in Kotlin Flow or Channels? Context: I am developing an Android app which receives data from a device via Bluetooth and then graphs it in real-time.

What's this sessions folder, no one seems to know really...

Hey friends, I am using ktlint via Spotless in my project, I see ktlint notifies about wildcard import / wrong indentation errors in console, but doesn’t auto fix them, I am seeing issue log and its mentioned somewhere its possible with --experimental flag, did anyone managed to get it working with spotless?

https://twitter.com/kotlin/status/1283341972032368640 If you want to store some nullable values in a non-nullable list (or set), you don’t have to null-check manually. Instead, use the listOfNotNull() function (and, starting with Kotlin 1.4, setOfNotNull()). #KotlinTips https://t.co/LTcIumU4wb Twitter

Hmm, taking it a step back: can inline classes even be generic?

https://twitter.com/kotlin/status/1283741388115513345 Kotlin 1.4-M3 introduces new modes for generating default methods in interfaces! Read more: https://kotl.in/1_4_M3_JVMDefault Twitter

Kotlin 1.4-M3: Generating Default Methods in Interfaces In Kotlin 1.4, we’re adding new experimental ways for generating default methods in interfaces in the bytecode for the Java 8 target. Later, we’re going to be deprecating the @JvmDefault annotation in favor of generating all the method bodies in interfaces directly when the code is compiled in a special mode. Read more details of […]

Question for Kotlin Superman: Could this issue be the result of myself trying to use a java package in kotlin? Is there anything special I need to consider when doing something like that? I've always had issues doing it and this one is driving me mad. https://github.com/docker-java/docker-java/issues/1437

at the same time I also explore a bit on

iOS

. Some of the users there pointed

<http://hackingwithswift.com|hackingwithswift.com>

as a good beginning resource to learn

iOS dev

.. is there any similar one for

android?

Heya! I’m trying to find some ideas on how to handle Etags on the client-side from within Webflux http client(WebClient.Builder) Wondering if it would build the response based on the server’s response(cached payload if 304 or a new one if 200). Something similar to the way that Retrofit2 does. Anyone?

Hey Everyone, I need a little help. I have 2 classes which uses RxJava which I need to convert it in to Coroutines/Flow. If you guys can help me out that would be great. Thanks in advance. ViewModel

abstract class MviViewModel<I : MviIntent, A : MviResult<VS>, VS : MviViewState>(initialState: VS) : ViewModel() {

    private val intentsSubject: PublishSubject<I> = PublishSubject.create()


    private val statesObservable: Observable<VS> = intentsSubject
        .compose { intents -> intents.publish { shared -> filterIntents(shared) } }
        .flatMap { dispatchIntent(it) }
        .scan(initialState) { previousState: VS, result: A -> result.reduce(previousState) }
        .distinctUntilChanged()
        .replay(1)
        .autoConnect(0)

    abstract fun dispatchIntent(intent: I): Observable<A>
    
    open fun filterIntents(intents: Observable<I>): ObservableSource<I> = intents

    fun processIntents(intents: Observable<I>): Disposable {
        return intents.subscribe(intentsSubject::onNext)
    }

    fun states(): Observable<VS> = statesObservable
}

interface MviAnalyticsViewModel {
    fun onResume(activity: Activity)

}

Fragment

abstract class MviFragment<V : MviView, I : MviIntent, A : MviResult<VS>, VS : MviViewState> : Fragment(), MviView {

    private val onStartDisposables = CompositeDisposable()
    private val onAttachDisposables = CompositeDisposable()


    /**
     * This activity should implement the provided MviView generic interface, it will be used by
     * the renderer to update the ui.
     */
    abstract val view: V

    /**
     * The ViewModel belonging to the activity
     */
    abstract val viewModel: MviViewModel<I, A, VS>

    /**
     * The Renderer that will update the MviView of this activity
     */
    abstract val renderer: MviRenderer<V, VS>

    /**
     * Push Intents to this
     */
    abstract fun onStartIntents(): Observable<I>
    abstract fun onStartIntentsFlow(): Flow<I>

    /**
     * Push Intents to this
     */
    open fun onAttachIntents(): Observable<I> = Observable.empty()

    open fun onAttachIntentsFlow(): Flow<I> = emptyFlow()

    override fun onAttach(context: Context) = super.onAttach(context).also {
        AndroidSupportInjection.inject(this)
        onAttachDisposables.add(viewModel.processIntents(onAttachIntents()))

    }

    @ExperimentalCoroutinesApi
    override fun onDetach() {
        onAttachDisposables.clear()

        super.onDetach()
    }

    override fun onStart() = super.onStart().also {
        onStartDisposables.addAll(
            viewModel.states()
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe { renderer.render(view, it) },
            viewModel.processIntents(onStartIntents())
        )
    }

    @ExperimentalCoroutinesApi
    override fun onStop() {
        onStartDisposables.clear()

        super.onStop()
    }
}