CODEWITHSUNDEEP
dependency-injectionkotlinkodein
atok
atok

Reputation: 5948

How to get a list of bound singleton instances of one type?

Given a kodein instance:

interface SharedInterface {}

class A : SharedInterface
class B : SharedInterface
class C : SharedInterface
class D

fun main(args: Array<String>) {

    val kodein = Kodein {
       bind<A>() with singleton { A() }
       bind<B>() with singleton { B() }
       bind<C>() with singleton { C() }
       bind<D>() with singleton { D() }
    }
}

Is there a way to get instances of A, B, C but not D from kodein?

The closest I got was:

val singletonBindings = kodein.container.bindings.filterValues { it is SingletonBinding<*> }
val singletonInstances = singletonBindings.map { it.value.getInstance(???, ???, Unit) }

Set binding was of little help as I was not able to bind single instance as set-enabled-type and the type I want it to be bound as:

interface SharedInterface {}

class A : SharedInterface
class B : SharedInterface
class C : SharedInterface
class D

fun main(args: Array<String>) {

    val kodein = Kodein {
        bind() from setBinding<SharedInterface>()

        bind<A>().inSet() with singleton { A() }
        bind<B>().inSet() with singleton { B() }
        bind<C>().inSet() with singleton { C() }
        bind<D>().inSet() with singleton { D() }
    }

    val shared = kodein.instance<Set<SharedInterface>>()
}

Causes Exception in thread "main" java.lang.IllegalStateException: No set binding to bind<Set<out A>>() with ? { ? }

This fixes the issue but is ugly:

  val kodein = Kodein {
        bind() from setBinding<SharedInterface>()

        bind<SharedInterface>().inSet() with singleton { instance<A>() }
        bind<SharedInterface>().inSet() with singleton { instance<B>() }
        bind<SharedInterface>().inSet() with singleton { instance<C>() }

        bind<A>() with singleton { A() }
        bind<B>() with singleton { B() }
        bind<C>() with singleton { C() }
        bind<D>() with singleton { D() }
    }

    val shared = kodein.instance<Set<SharedInterface>>()

Upvotes: 0

Views: 639

Answers (1)

Salomon BRYS
Salomon BRYS

Reputation: 9584

There is no way in Kodein 4 to do that other than what you just did. Can you open a ticket on Kodein's GitHub ? I may have time to squeeze that into Kodein 5 ;)

Upvotes: 2

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