Kodein is a very simple and yet very useful dependency retrieval container. it is very easy to use and configure.

Kodein allows you to:

• Lazily instantiate your dependencies when needed
• Stop caring about dependency initialization order
• Easily bind classes or interfaces to their instance or provider
• Easily debug your dependency bindings and recursions

Kodein does not allow you to:

• Automatically instantiate your dependencies via injected constructor and reflexivity. For that, you need Guice.
• Have dependency injection validated at compile time. For that, you need Dagger.

Kodein is a good choice because:

• It is small, fast and optimized (makes extensive use of inline)
• It proposes a very simple and readable declarative DSL
• It is not subject to type erasure (like Java)
• It integrates nicely with Android
• It proposes a very kotlin-esque idiomatic API
• It can be used in plain Java

An example is always better than a thousand words:

val kodein = Kodein {
    bind<Dice>() with provider { RandomDice(0, 5) }
    bind<DataSource>() with singleton { SqliteDS.open("path/to/file") }
}

class Controller(private kodein: Kodein) {
    private val ds: DataSource = kodein.instance()
}

Kodein version 3 is the current major version available:

• Kodein 3 full documentation
• Kodein 3 API reference

If you are currently using a javax.inject compatible dependency injection library and whish to migrate to Kodein, there is a guide for that.

Well, I'd like to know!

If you are using Kodein, please let me know by mail.

A public list will be displayed here soon :)