KojextExtras (Experimental)

Experimental

KojectExtras is experimental and the API may change in the future.

Koject creates a dependency graph at compile time, but sometimes you may need to add types created on a platform at runtime. KojectExtras allows you to add dependencies at the start of Koject.

How to Use

tip

Dependencies should be provided using the @Provides annotation as much as possible, and KojectExtras should be used when that is not possible.

First, implement the KojectExtras interface and declare additional types to be provided using properties.

@ExperimentalKojectApi
class PlatformExtras(
    val platformClass: PlatformClass // provide PlatformClass
): KojectExtras

Then specify its extras when calling Koject.start(). If not specified, MissingExtrasException is thrown.

fun main() {
    val platformExtras = PlatformExtras(/* ... */)
    Koject.start {
        @OptIn(ExperimentalKojectApi::class)
        addExtras(platformExtras)
    }
}

This allows PlatformClass to be injected.

@Provides
class SomeClass(
    val platformClass: PlatformClass, // can be injected
)

class SomeClass {
    val platformClass: PlatformClass = inject() // can be injected
}

Advanced usage

In KojectExtras, all non-private properties are treated as provides, and getters are also available.

@ExperimentalKojectApi
class GlobalExtras(
    // provide SomeClass1
    val someClass1: SomeClass1
): KojectExtras {
    // provide SomeClass2
    val someClass2: SomeClass2 = SomeClass2()

    // provide SomeClass3
    val someClass3: SomeClass3
        get() = SomeClass3()
}

@Singleton, @Qualifier and @Named annotations can be used.

@ExperimentalKojectApi
class GlobalExtras(
    // provide as singleton
    @Singleton
    val someClass1: SomeClass1
): KojectExtras {
    // provide with a qualifier
    @SomeQualifier
    val someClass2: SomeClass2 = SomeClass2()

    // provide with a name
    @Named("some-name")
    val someClass3: SomeClass3
        get() = SomeClass3()
}

@KojectExtrasMessage can be used to change the error message when that extras is not set.

@ExperimentalKojectApi
@KojectExtrasMessage("error message for GlobalExtras")
class GlobalExtras(
    val someClass: SomeClass
): KojectExtras