Scala

Strange Scalatra issue that halt does not work when trait JacksonJsonSupport is mixed in

/ nidkil / Leave a comment

I am running Scala version 2.11.1 and Scalatra version 2.3.0 and had a strange problem that plain vanilla halt does not work when the trait JacksonJsonSupport is mixed in with my controller class. Here are two simpel code snippets to illustrate the problem. Continue reading →

Error compiling Scalatra project

/ nidkil / Leave a comment

Seriously? Unsupported major.minor version 51.0 when compiling a Scalatra project? The complete error is “Caused by: java.lang.UnsupportedClassVersionError: org/eclipse/jetty/server/Handler : Unsupported major.minor version 51.0”. After some Googling I found the following statement “You are using different JDK versions to compile and run the application”. No way, that is not possible. Continue reading →

Installing Scalatra on Windows

/ nidkil / Leave a comment

Scalatra is a micro framework for Scala. Installation does not seem to be as straight forward as adding Scalatra to the dependencies of build.sbt. It requires a number of other tools to work: Conscript and giter8. Conscript is a tool for installing and updating Scala code. giter8, which depends on conscript, allows you to check out project templates directly from Github. It’s the recommended way to generate Scalatra project skeletons. These are quick installation instructions for Scalatra on Windows. Continue reading →

sbt cannot find play-json_2.11 library

/ nidkil / Leave a comment

Grrrr, just cloned some of my code from Github to my laptop. I initially worked on this code on my desktop. When I tried to compile it in sbt I got the following error sbt.ResolveException: unresolved dependency: com.typesafe.play#play-json_2.11;2.3.0: not found. It had been a while since I worked on the code so I was puzzled. It turns out there are problems with the Typesafe repository. As a workaround the repository needs to be added as a resolver to the build.sbt file.

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

After this it compiled nicely. Sweet. Happy coding 🙂

What happened to akka.util.duration?

/ nidkil / Leave a comment

In a lot of old Akka examples you will see the following statements:

import akka.util.Timeout
import akka.util.duration._
implicit val askTimeout = Timeout(1 second)

This will give error ‘object duration is not a member of package akka.util’. It turns out duration is now included in Scala standard library. To fix the error use the following import statement:

import scala.concurrent.duration._

Check out the migration guide for other pieces of Akka functionality that have moved to Scala.

Executing a method defined in a configuration file

/ nidkil / Leave a comment

I have a class with a method that takes a function as parameter. This function is the strategy that determines how a file is split into chunks. This is the signature of the method.

def split(r: RemoteFileInfo, append: Boolean, workDir: File, strategy: (Long) => Int = defaultStrategy): LinkedHashSet[Chunk] = {
  ...
}

There is a companion object that provides a number of predefined strategies. I wanted to make the strategy configurable by adding it to the Akka application.conf file. Continue reading →