Scala Cookbook

13.1. Getting Started with a Simple Actor

Problem

You want to begin using actors to build concurrency into your applications.

Solution

Create an actor by extending the akka.actor.Actor class and writing a receive method in your class. The receive method should be implemented with a case statement that allows the actor to respond to the different messages it receives.

To demonstrate this, create an SBT project directory named HelloAkka, move into that directory, and then add the necessary Akka resolver and dependency information to your build.sbt file:

name := "Hello Test #1"

version := "1.0"

scalaVersion := "2.10.0"

resolvers += "Typesafe Repository" at  "http://repo.typesafe.com/typesafe/releases/"

libraryDependencies += "com.typesafe.akka" %% "akka-actor" % "2.1.2"

Note

At the time of this writing, the Akka actor library is being migrated into the Scala distribution, but it’s still necessary to include the library as a dependency in your SBT build.sbt file (or download the necessary JAR files manually). This may change in the future, in which case the dependencies shown in this chapter may not be necessary.

Next, define an actor that responds when it receives the String literal hello as a message. To do this, save the following source code to a file named Hello.scala in the root directory of your SBT project. Notice how the literal hello is used in the first case statement in the receive method of the HelloActor class:

import akka.actor.Actor
import akka.actor.ActorSystem
import akka.actor.Props ...