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The Dancer Upstairs

The Dancer Upstairs may be a little slow for most other people, but it’s one of my favorite movies (except for the dog parts).

Released in 2002, it was the first or second movie I saw Javier Bardem in, and when you watch it not knowing who he is, you say to yourself, “This guy has it,” that special something that makes you want to watch. As a friend once said, Tom Hanks is like that; if they made a movie about a guy stranded on an island and he was the only one in the movie, she’d watch the movie just because it was him (as did many other people).

An introduction to Akka Actors

Table of Contents1 - An Akka “Hello, world” example2 - A second example3 - More examples4 - Where Akka fits in5 - Source code6 - Key points7 - See also

This is an excerpt from my book, Hello, Scala. In this lesson I’ll show two examples of applications that use Akka actors, both of which can help you get started with my larger “Alexa written with Akka” = Aleka application.

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An Akka “Hello, world” example

First, let’s look at an example of how to write a “Hello, world” application using Akka.

Writing a “Hello” actor

An actor is an instance of the akka.actor.Actor class, and once it’s created it starts running on a parallel thread, and all it does is respond to messages that are sent to it. For this “Hello, world” example I want an actor that responds to “hello” messages, so I start with code like this:

Stuart Margolin and Northern Exposure

I watched an episode of Northern Exposure recently and at the end of it I was surprised to see that Stuart Margolin directed the episode. I always enjoyed his characters on The Rockford Files and M*A*S*H, and I remembered seeing him on Magnum, P.I., but I didn’t know anything else about his career, including that he was a director. After reading his Wikipedia entry I hope at some point to see the episode of 30 Rock he did with Alan Alda.

How to write Akka Actors: An example video game

Way back in 2013 — before my first fake heart attack followed by learning that I had thyroid cancer — I thought I was about to go “back to work”, and I decided to try to write another visual demo of Akka Actors before I went back to work. I gave myself 10 hours to write something, and at first I decided to just create some bubbles that would move about randomly on screen. But I got that working so fast that I decided to do something else.

Eventually I came up with the idea of a little “kill the bubbles” game, which turned into a “kill the characters” game. This video shows how it works:

An Akka actors ‘remote’ example

While doing some crazy things with SARAH, I realized that the best way to solve a particular problem was to use remote Akka actors. I haven’t had the opportunity to work with Akka much since finishing the Scala Cookbook, so I dug around trying to find a simple Akka remote “Hello, world” example. Unable to find a good one, I read some stuff, and created it myself.