I was wondering if it was possible to group a call to a function that is present for two different types, without having to create two branches in the "when" statement.
For example, in my case I have this class extensions:
// File: PublisherExtensions.kt
fun <T> Mono<T>.toServiceResponse(): Mono<Response<T>> =
this.map { r -> Response(true, r, null) }
.onErrorResume { e -> Mono.just(Response(false, null, Response.Error(500, e.message))) }
fun <T> Flux<T>.toServiceResponse(): Mono<Response<List<T>>> =
this.collectList()
.map { r -> Response(true, r, null) }
.onErrorResume { e -> Mono.just(Response(false, null, Response.Error(500, e.message))) }
And what I use with them is this statement:
val body = when (val value = result.returnValue) {
is Mono<*> -> value.toServiceResponse()
is Flux<*> -> value.toServiceResponse()
else -> throw RuntimeException("The \"body\" should be Mono<*> or Flux<*>!")
}
While what I would like would be this:
val body = when (val value = result.returnValue) {
is Mono<*>, is Flux<*> -> value.toServiceResponse()
else -> throw RuntimeException("The \"body\" should be Mono<*> or Flux<*>!")
}
The IDE gives me this error:
Unresolved reference.
None of the following candidates is applicable because of receiver type mismatch:
- public fun Flux<TypeVariable(T)>.toServiceResponse(): Mono<Response<List<TypeVariable(T)>>> defined in brc.studybuddy.backend.wrapper.util in file PublisherExtensions.kt
- public fun Mono<TypeVariable(T)>.toServiceResponse(): Mono<Response<TypeVariable(T)>> defined in brc.studybuddy.backend.wrapper.util in file PublisherExtensions.kt
Notice that the second toServiceResponse can be defined in terms of the first:
fun <T> Flux<T>.toServiceResponse(): Mono<Response<List<T>>> =
this.collectList().toServiceResponse()
So you are almost doing the same thing on Monos and Fluxes, except that for Fluxes, you also call collectList first.
val body = when (val value = result.returnValue) {
is Mono<*> -> value
is Flux<*> -> value.collectList()
else -> throw RuntimeException("The \"body\" should be Mono<*> or Flux<*>!")
}.toServiceResponse()
Alternatively, without a when:
val body = result.returnValue.let { value ->
(value as? Flux<*>)?.collectList()
?: (value as? Mono<*>)
?: throw RuntimeException("The \"body\" should be Mono<*> or Flux<*>!")
}.toServiceResponse()