akka-guice

What?

This is a very simple (so very stable) scala library for injecting Akka using Guice.

Why?

Google search akka guice => some articles:

• Akka Dependency Injection => just a guide.

• Akka Scala Guice Activator => just a (complex) demo.

• Akka Guice Integration for Playframework => I think akka-guice integration should NOT depends on Play!

=> So I create this library :D

How?

1. install akka-guice from maven center ex, add to build.sbt: libraryDependencies += "com.sandinh" %% "akka-guice" % "3.2.0"

2. use akka-guice

see the test files & source code for detail. It's very simple!

• ChildActor: The foo parameter will be injected

class ChildActor @Inject() (@Named("fooName") foo: String) extends Actor ...

• AssistedChildActor: Sometimes an Actor gets some of its constructor parameters from the Guice Injector and others from the caller.

  Parameter foo of AssistedChildActor's constructor is taken from Guice. arg1 & arg2 from the caller.

class AssistedChildActor(foo: String, arg1: Int, arg2: String) extends Actor ...

object AssistedChildActor {
  class Factory @Inject() (@Named("fooName") foo: String) extends ActorFactory[AssistedChildActor] {
    def create(args: Any*): AssistedChildActor = args match {
      case Seq(arg1: Int, arg2: String) => new AssistedChildActor(foo, arg1, arg2)
      case _                            => throw new IllegalArgumentException
    }
  }
}

• ParentActor: extends com.sandinh.akuice.ActorInject & use injectActor method to inject child actors. The injectActor method need an implicit akka.actor.ActorRefFactory to create actor (using ActorRefFactory#actorOf method).

  ParentActor extends Actor => it has an implicit val context: ActorContext (ActorContext extends ActorRefFactory).

class ParentActor @Inject() (val injector: Injector) extends Actor with ActorInject {
  private val child1 = injectActor[ChildActor]
  private val child2 = injectActor[ChildActor]("child2")
  private val assistedChild = injectActor[AssistedChildActor, AssistedChildActor.Factory](1, "arg2 value")
  ...
}

• Service.scala: This is not an Actor but because it extends com.sandinh.akuice.ActorInject => we can use injectTopActor method.

  Note that, we can also use injectActor method. The injected actor will be a child of the implicit ActorRefFactory in the scope.

@Singleton
class Service @Inject() (val injector: Injector) extends ActorInject {
  private val parentRef = injectTopActor[ParentActor]

  def hello(sender: ActorRef) = parentRef.tell("hello!", sender)
}

• AkkaModule:

class AkkaModule(system: ActorSystem) extends AbstractModule {
  def configure(): Unit = {
    bind(classOf[ActorSystem]).toInstance(system)
    //other binds
  }
}

• AkuiceSpec:

"Akuice" must {
    "inject actors: receive replied messages when call Service.hello" in {
      val injector = Guice.createInjector(new AkkaModule(system))
      val service = injector.getInstance(classOf[Service])
      service.hello(self)

      //expectMsg ...
    }
  }

Changelogs

see CHANGES.md

Licence

This software is licensed under the Apache 2 license: http://www.apache.org/licenses/LICENSE-2.0

Copyright 2014-2017 Sân Đình (http://sandinh.com)