cake-pattern

I'm trying to implement dependency injection in Scala with the Cake Pattern, but am running into dependency collisions. Since I could not find a detailed example with such dependencies, here's my problem: Suppose we have the following trait (with 2 implementations): trait HttpClient { def get(url: String) } class DefaultHttpClient1 extends HttpClient { def get(url: String) = ??? } class DefaultHttpClient2 extends HttpClient { def get(url: String) = ??? } And the following two cake pattern modules (which in this example are both APIs that depend on our HttpClient for their functionality): trait

I'm confused how to ensure that my Actors have the appropriate dependencies using the cake pattern. I'm still getting to grips with this, and I can't find any examples anywhere. I'm basically just looking for a tutorial/resource to follow. Cheers, Chris. Actors as dependency: trait DBComponent { def db: ActorRef // no compile time guarantees type K type V object DBActor { case class Put(key: K, value: V) case class Get(key: K) } class DBActor { import DBActor._ val db = scala.collection.mutable.Map.empty[K, V] def receive = { case Put(k, v) => db.put(k, v) case Get(k) => sender ! db.get(k) } }

Following from this question, I have now the following: case class Pet(val name: String) trait ConfigComponent { type Config def config: Config } trait VetModule extends ConfigComponent { type Config <: VetModuleConfig def vet: Vet trait Vet { def vaccinate(pet: Pet) } trait VetModuleConfig { def extra: String } } trait VetModuleImpl extends VetModule { override def vet: Vet = VetImpl object VetImpl extends Vet { def vaccinate(pet: Pet) = println("Vaccinate:" + pet + " " + config.extra) } } trait AnotherModule extends ConfigComponent { type Config <: AnotherConfig def getLastName(): String

I'm currently working to use the cake pattern on my application. On exemples I have found across the web the exemples are kind of basic but doesn't involve more complex needs. What I'd like to do is not so fancy: I would like to have inside a cake pattern application, 2 services of the same type, using different implementations. trait UserServiceComponent { self: UserRepositoryComponent => val userService: UserService class DefaultUserService extends UserService { def getPublicProfile(id: String): Either[Error, User] = userRepository.getPublicProfile(id) } class AlternativeUserService extends

I have been reading about doing Dependency Injection in scala via the cake pattern . I think I understand it but I must have missed something because I still can't see the point in it! Why is it preferable to declare dependencies via self types rather than just abstract fields? Given the example in Programming Scala TwitterClientComponent declares dependencies like this using the cake pattern: //other trait declarations elided for clarity ... trait TwitterClientComponent { self: TwitterClientUIComponent with TwitterLocalCacheComponent with TwitterServiceComponent => val client: TwitterClient