Working out the Fibonacci numbers are a standard exercise when learning a programming language, or just refreshing your knowledge. This is a recap of various ways to calculate them in Scala. All the code is available in a handy gist.
I've been using Akka Camel and ActiveMQ recently, as part of a delayed worker-queue system. Given the lack of good googleable information about combining the two, I thought it would be useful if I explained briefly how to get Akka Camel and ActiveMQ to work together in the form of a quick example.
Using a DSL to write a test can prove to be useful, especially when there are lots of prerequisites, or the problem is complex. Having a test that is incredibly readable reduces complexity overhead and aids reader comprehension. Any tests that require the reader to retain a mental map could benefit from a DSL.
Scala has three different frameworks for writing unit tests, JUnit, Specs2 and ScalaTest. I have mainly been using ScalaTest since I started to learn Scala about four months ago. One of the areas I have been concentrating on is how to write good assertions. Specifically, ones that yield easily diagnosable error messages when they fail.
TTL Collections were introduced in MongoDB 2.2. You are now able to create an index which triggers the deletion of a document after the Time-To-Live (TTL) time passes.
I was recently writing a cache for MP3s at work, and I needed to test some private methods. Testing a private method in Java is doable using reflection.