day3 actors

scala/build.sbt

@@ -6,3 +6,4 @@ scalaVersion := "2.13.1"
 
 libraryDependencies += "org.scalactic" %% "scalactic" % "3.0.8"
 libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.8" % "test"
+libraryDependencies += "com.typesafe.akka" %% "akka-actor"   % "2.6.0"

scala/src/main/scala/day3/ActOne.scala

@@ -0,0 +1,19 @@
+package day3
+import akka.actor.Actor;
+import akka.actor.ActorSystem;
+import akka.actor.Props
+
+class HelloActor extends Actor {
+  def receive: Actor.Receive = {
+    case "hello" => println("Hi")
+    case _ => println("Wut")
+  }
+}
+
+object ActOne extends App {
+  val system = ActorSystem("ActOne")
+  val act = system.actorOf(Props[HelloActor], name = "alice")
+  act ! "hello"
+  act ! "one"
+
+}

scala/src/main/scala/day3/LoadPages.scala

@@ -0,0 +1,63 @@
+package day3
+import akka.actor.Actor;
+import akka.pattern.ask;
+import akka.actor.ActorSystem;
+import akka.actor.Props
+import akka.util.Timeout;
+import scala.io.Source
+import scala.concurrent.duration._;
+import scala.concurrent.{Await, ExecutionContext, Future}
+
+
+case class Get(url : String)
+
+object Fetch {
+  def getPageSize(url: String) = Source.fromURL(url).mkString.length()
+}
+
+class PageLoader extends Actor {
+
+  def receive: Actor.Receive = {
+    case Get(url) => sender ! Fetch.getPageSize(url)
+  }
+}
+
+object LoadPages extends App {
+  val system = ActorSystem("ActOne")
+  val urls = List(
+    "http://www.amazon.com",
+    "http://jxs.me",
+    "http://www.example.com",
+    "http://sdf.org"
+  )
+
+
+  def timeMethod(method: () => Unit) = {
+    val start = System.nanoTime
+    method()
+    val end = System.nanoTime
+    println("Method took " + (end - start) / 1000000000.0 + " seconds.")
+  }
+
+  def getPageSizeSequentially() = {
+    for (url <- urls) {
+      println("Size for " + url + ": " + Fetch.getPageSize(url))
+    }
+  }
+
+  def getPageSizeConcurrently() = {
+    implicit val timeout = Timeout(5.seconds)
+    val futures = urls.map(url => {
+      val act = system.actorOf(Props[PageLoader], name = url.replace("/", ""))
+      act ? Get(url)
+    })
+    for (future <- futures) {
+      val result = Await.result(future, timeout.duration)
+      println(result)
+    }
+  }
+
+  timeMethod { getPageSizeSequentially }
+  timeMethod { getPageSizeConcurrently }
+
+}