Doxia macro for
Java Scala
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Feeding more of that fast build-test-code loop addiction


After using ruby rspec autotest and spork for a while i got addicted. The enormous speed and satisfaction you get from
being able to run your tests on every save. The quick feedback loop makes my day a joy. I thought this was a dynamic
language feature, turns out its a build system feature. I came to the conclusion after doing scala and sbt development.
And now i am going to show how you can get this killer feature in your pure java project. This is a write up of transforming
a maven project made by Rune Flobakk. You can find my fork at

Most likely you are using maven for you builds. If not read on any way sbt will probably be able to help you as well.
After ensuring that ‘’mvn test’’ runs green, run sbt in your project folder. It will ask you some questions about your
project, sbt version and scala version. In a javaproject, you are well of by using the defaults. You have now downloaded
scala but you will probably want to use that in the future any way.

Sbt is now running, and all commands from her on is issued inside the console. This saves you from that pesky jvm boot
delay. In sbt dependencies are specified through a project class rather than in a xml file. It is located under
project/build/Project.scala. The name of the class can be anything you like. Sbt will not require you to have a build
and project class, however to configure to do more than the absolute basic you have to create one.

I have created the following:

import sbt._

class Project(info: ProjectInfo) extends DefaultProject(info){

val doxiaCore = “org.apache.maven.doxia” % “doxia-core” % “1.1.2” val doxiaApi = “org.apache.maven.doxia” % “doxia-sink-api” % “1.1.2” val commonsLang = “commons-lang” % “commons-lang” % “2.5” val mockito = “org.mockito” % “mockito-all” % “1.8.4” % “test” val junit = “junit” % “junit” % “4.8.2” % “test”


As you can see this scala code, and we extend DefaultProject. It is located in sbt.DefaultProject hence the import. In
sbt you have to run ’’update’’ explicitly in contrast to maven where it is done whenever.

Each of the pom.xml dependencies like this

org.apache.maven.doxia doxia-core 1.1.2

is translated into

val doxiaCore = “org.apache.maven.doxia” % “doxia-core” % “1.1.2”

the “magic” lies in the % which is part of the sbt DSL for specifying dependencies. Now by running;
’’reload’’, which recompiles the project file it self.
’’update’’, which downloads all the dependencies and
’’compile’’, which.. compiles the source and now runs.

Woho the project is build with sbt.

T for test in that test-code-build loop

By running ’’test’’, sbts testing command, you’ll see that something is’nt ok. None of the tests are executed. Since sbt
normally uses scala test frameworks it is’nt accustom to jUnit. Lucky for us sbt is easily extended and some one has done
it before us. Got to love that community!

To make sbt understand jUnit we have to change the project file to use a jUnit interface. Like so:

import sbt._

class Project(info: ProjectInfo) extends DefaultProject(info){

val doxiaCore = “org.apache.maven.doxia” % “doxia-core” % “1.1.2” val doxiaApi = “org.apache.maven.doxia” % “doxia-sink-api” % “1.1.2” val commonsLang = “commons-lang” % “commons-lang” % “2.5” val mockito = “org.mockito” % “mockito-all” % “1.8.4” % “test” val junit = “junit” % “junit” % “4.8.2” % “test” val bryanjswift = “Bryan J Swift Repository” at “” val junitInterface = “com.novocode” % “junit-interface” % “0.4.0” % “test” override def testFrameworks = super.testFrameworks ++ List(new TestFramework(“com.novocode.junit.JUnitFrameworkNoMarker”))


This makes sbt understand jUnit test suites in the same way as it understands spec and scalatest. The junit-interface
is located in Bryan J Swifts repo which we refereed to by doing;

val bryanjswift = “Bryan J Swift Repository” at “”

Where ’’at’’ is the keyword telling sbt that Bryans repo is located at the url. So fluent that i nearly never look
it up. Nice! The next cool thing is that we override the testFrameworks method and make it return the original frameworks appending
the jUnit interface. This is a good example of you extend sbt.

Now by running ’’reload’’, ’’update’’ and ’’test’’ we are in business.

L in loop in that test-code-build loop

To be able to get sbt to keep up with your pace there is a special command ‘’~’‘. What ’’~’’ does is run the command
preceding it for every change on the file system. Which in practice is every time you save a file. This is the same
mechanism autotest uses to keep up with your ruby coding.

So we are now familiar with the ‘’~test’’ but still I want to get back to ruby and autotest. Since autotest understands
which tests are required to run it does’nt run all the others. A nifty feature that saves me a lot of time. Autotest is
only guessing which files it need to run based on the location and name of the files you just saved. Sbt can do the very
same thing, but sbt can base the selection on which classes you changed and which tests are dependent on those. Sbt does
this when you say ‘’test-quick’’

So there we are back in that crazy test-build-code loop, but only now we are writing java.

~ test-quick