如何从 java class 访问 kotlin 代码

Question

Hi I have a kotlin use case which I want to call from java code how can I do that. this is what I have tried

this is my use case

@PerApp
class OnStandUseCase @Inject constructor(
    private val orderRepository: OrderRepository,
    private val serviceOrderTypeProvider: ServiceOrderTypeProvider
) : UseCaseCoroutine<GenericResponse, OnStandUseCase.Params>() {

    override suspend fun run(params: Params) = orderRepository.notifyOnStand(
        serviceOrderTypeProvider.apiPathFor(params.serviceType),
        params.id,
        params.action
    )

    data class Params(val serviceType: String, val id: String, val action: TimestampedAction)
}

UseCaseCoroutine

abstract class UseCaseCoroutine<out Type, in Params> where Type : Any {

    abstract suspend fun run(params: Params): Type

    operator fun invoke(params: Params, onResult: (type: Type) -> Unit = {}) {
        val job = GlobalScope.async(Dispatchers.IO) { run(params) }
        GlobalScope.launch(Dispatchers.Main) { onResult(job.await()) }
    }
}

This is how I call it from my kotlin class

  try {
            onStandUseCase(OnStandUseCase.Params(serviceType, id, action)) {
                callback.invoke(it)
            }
        } catch (exception: Exception) {
            onStandResponseErrors()
        }

But what is the equivalant to call from java class

this is what I tried

 onStandUseCase.run(new OnStandUseCase.Params("abcd", "1", new TimestampedAction("1","2"))){
            
        }

I get an error Expected 2 arguments but found only one

Not exactly sure what is the right way to call the use case from java code

any suggestions please

thanks R

Answer 1

You cannot call suspend functions from Java. (You technically could, but doing it correctly would be extremely difficult, and I strongly recommend you just avoid even trying.)

In your Kotlin code, write a function that is not a suspend function that converts it to an appropriate Java idiom -- an RxJava result, or a future. Call that method from Java instead.