Generics question, I’ve defined an interface for m...

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[zsperske]

Generics question, I’ve defined an interface for my factories and I’m trying to create a mapping so I can pass in the class of an Event & get back the factory which can create it.

interface SchemaFactory<in E: Event, out S: Schema> {

  fun create(event: E) : S
}

class TestEventFactory : SchemaFactory<TestEvent, TestEventSchema>

private val factories: Map<Class<out Event>, SchemaFactory<Event, Schema>> = mapOf(TestEvent::class.java to TestEventFactory())

However I get the following error message on `factories`:

Type mismatch.
Required:
Map<Class<out Event>, SchemaFactory<Event, Schema>>
Found:
Map<Class<out Event>, TestEventFactory>

[zsperske]

how would I define a map of factories that can only take in an event which matches their key in the map?

[zsperske]

interesting, I’ll give this a shot. thank you!

[zsperske]

is there a safer approach to this? seems like a somewhat common usecase

[zsperske]

I see, I guess I meant is there a standard approach to what I’m trying to do

[zsperske]

fair enough! thank you for your time and all this detail 🙂

[ephemient]

there are type-safe maps, but they can't be Map

[ephemient]

CoroutineContext/.Element/.Key is one of them in stdlib