These days I work on Rug, Atomist’s library for coding code modifications. Adding a feature, I start by creating a test. While it’s tempting to create a narrow test around the piece of code I want to change, it’s better to create an API-level test. Testing at the outside has a few benefits: it tells …
“Add a pom to my toy Scala project so I can build it with Maven” sounds simple. It is, if you do it every day. I can look it up, yet again. And get it wrong, yet again. And consult an expert with “Why doesn’t it see my Scala sources! This works fine from the …
You can watch the full keynote from Scala eXchange 2015 (account creation required, but free). The talk includes examples and details; this post is a summary of one thread. Scala is a scalable language, from small abstractions to large ones. This helps with the one scaling problem every software system has: scaling the feature set …
by Jorge Montero Maybe you are interested in a language, or an open source project, but you feel like the community is unwelcoming: Some big voices are rude, they’re downright hostile to newcomers and anyone who disagrees with them. Let’s not get involved. Or in your workplace: influential people in the organization aren’t nearly as …
or, “Everything You Never Wanted to Know About java.util.concurrent.ExecutorService But Needed To” from StrangeLoop, 18 Sep 2014 Abstract: A careful design lets you write a concurrent application without thinking about deadlock or synchronization. Getting to that design takes a lot of thinking. This session delivers the background you need to make good decisions about concurrency …
Why replace our carefully chosen, exactingly specified example-based tests with properties, when properties are harder to write and less specific? link to YouTube Video from Midwest.io 2014 Related code: https://github.com/jessitron/scalacheck-prisoners-dilemma
When testing akka code, I want to make sure a particular actor gets shut down within a time limit. I used to do it like this: Thread.sleep(2.seconds) assertTrue(actorRef.isTerminated()) That isTerminated method is deprecated since Akka 2.2, and good thing too, since my test was wasting everyone’s time. Today I’m doing this instead: import akka.testkit.TestProbeval probe = …
TL;DR – Clojure’s threading macro keeps code in a legible order, and it’s more extensible than methods. When we create methods in classes, we like that we’re grouping operations with related data. It’s a useful organizational scheme. There’s another reason to like methods: they put the code in an order that’s easy to read. In …
Today at work, I said, “I wish I could express the right level of encapsulation here.” Oh, but this is Scala! Many things are possible! We have a class, an akka Actor, whose job is to keep an eye on things. Let’s pretend its job is to clean up every so often: sweep the corners, …
In the left corner, we have Functional Programming. FP says, “Classes shall be immutable!” In the right corner, we have Object-Oriented programming. It says, “Classes shall be extendable!” The battlefield: define a method on the abstract class such that, when you call it, you get the same concrete class back. In Scala.Fight! Here comes the …