user service implementation

Implementations for the methods in UserService are provided in UserServiceImpl.scala. To do its job, the UserServiceImpl needs a SimblDomainModel repository, which is retrieved from the LongevityContext in SimblContextImpl.scala like so:

val longevityContext = LongevityContext[Future, SimblDomainModel]()
val repo = longevityContext.repo

The LongevityContext takes an implicit ExecutionContext when constructed with a Future effect. This will be used for all the repository operations. But UserServiceImpl will still need an execution context to compose the futures. Akka HTTP already needs an ExecutionContext to run, and SimblContextImpl provides an execution context that it pulls out of the Akka ActorSystem.

Here’s the scaffolding for UserServiceImpl, which shows how the class acquires its two dependencies:

package simbl.service

import longevity.persistence.Repo
import scala.concurrent.ExecutionContext
import scala.concurrent.Future
import simbl.domain.SimblDomainModel

/** default implementation of service to back the [[UserRoute user routes]] */
class UserServiceImpl(
  private val repo: Repo[Future, SimblDomainModel])(
  implicit context: ExecutionContext)
extends UserService {

  // ...

}

There are a number of service methods in UserServiceImpl. In this tutorial, we will focus on three: createUser, retrieveUser, and updateUser.