dics (DI component storage)

DI component storage with automatic removing and multiple parents support It consists of two base terms: DiContext and DiComponent

DiContext - Some scope or lifetime There are several default declared contexts:

• Application.diContext
• Activity.nonConfigDiContext
• Activity.diContext
• Fragment.nonConfigDiContext
• Fragment.diContext

DiComponent - Marker intarface for any DI component There are several default other markers:

• PermanentDiComponent
• ApplicationDiComponent
• ApplicationPermanentDiComponent
• ActivityNonConfigDiComponent
• ActivityDiComponent
• etc...

Some implementations ideas

• DiComponent can depend on several other ones.
• Instance of any DiComponent is stored in some DiContext.
• Instance of DiComponent can be obtained only from DiContext.
• Instance of DiComponent can be stored in one DiContext and obtained from another one.
• Instance of DiComponent is created lazily when it's obtained and is removed when it's not used by any DiContext.
• If DiComponent is PermanentDiComponent, it's not removed while DiContext where it's stored is alive.
• Activity.diContext and others like that are extension properties

Usage

1. Declare DiComponent and DiComponentFactory

class CoreComponent : ApplicationDiComponent {
    class Factory : DiComponentFactory<CoreComponent> {
        override fun createComponent(provider: DiComponentProvider): CoreComponent {
            return CoreComponent()
        }
    }
}

2. Create dependency from one DiComponent to another

class AppComponent : ApplicationDiComponent {
    class Factory : DiComponentFactory<AppComponent> {
        override fun createComponent(provider: DiComponentProvider): AppComponent {
            val coreComponent = provider.obtainComponent(CoreComponent::class)
            return AppComponent()
        }
    }
}

3. Register DiComponentFactory

class App : Application() {
    override fun onCreate() {
        super.onCreate()
        diContext.configure {
            registerComponentFactory(AppComponent.Factory())
            registerComponentFactory(CoreComponent.Factory())
        }
    }
}

4. Access DiComponent while activity is alive

class SomeActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val appComponent = diContext.obtainComponent(AppComponent::class)
    }
}

5. Declare DiComponent owner if it's not obvious.

class Level1Component : FragmentDiComponent {
    class Factory : DiComponentFactory<Level1Component> {
        override fun createComponent(provider: DiComponentProvider): Level1Component {
            return Level1Component()
        }
    }
}

class Level0Fragment : Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }
}

// Child of Level0Fragment
class Level1Fragment : Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        diContext.configure {
            setOwnerOf(Level1Component::class)
        }
        super.onCreate(savedInstanceState)
    }
}

// Child of Level1Fragment
class Level2Fragment : Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val level1Component = diContext.obtainComponent(Level1Component::class)
    }
}