Koin - single instance per parameter value

Question

I have a module:

single{ (name: String) -> Person(name) }

When I do:

val alice: Person by inject {parametersOf("Alice")}
val bob: Person by inject {parametersOf("Bob")}

I get 2 instances of Alice. All parameters other than the first are ignored.

Is there a simple way to make Koin treat those 2 as different? Parameters are not known in advance, so I can't use named properties. factory won't do either, I need to reuse instances with same parameter sets.

Answer 1

There is no such thing directly in Koin, but it's easy enough to make something that works this way.

1) a class that does create-if-not-present:

class DistinctFactory<K, V>(private val newInstance: (K) -> V) {
    private val _locker = Any()
    private val mRepo: HashMap<K, V> = HashMap()

    operator fun get(id: K): V {
        return mRepo[id] ?: run {
            synchronized(_locker) {
                mRepo[id] ?: run {
                    newInstance(id).also {
                        mRepo[id] = it
                    }
                }
            }
        }
    }
}

2) Koin single of DistinctFactory:

single { DistinctFactory<String, Person> { Person(it) } }

3) Koin factory that uses the previous single:

factory { (name: String) -> get<DistinctFactory<String, Person>>()[name] }

test:

val alice: Person by inject {parametersOf("Alice")}
val bob: Person by inject {parametersOf("Bob")}
val aliceAgain: Person by inject {parametersOf("Alice")}

alice === aliceAgain