Posts about technology and arts.

Using Apache Commons Functor functional interfaces with Java 8 lambdas

Apache Commons Functor (hereon [functor]) is an Apache Commons component that provides a functional programming API and several patterns implemented (visitor, generator, aggregator, etc). Java 8 has several nice new features, including lambda expressions and functional interfaces. In Java 8, lambdas or lambdas expressions are closures that can be evaluated and behave like anonymous methods.

Functional interfaces are interfaces with only one method. These interfaces can be used in lambdas and save you a lot of time from writing anonymous classes or even implementing the interfaces. [functor] provides several functional interfaces (thanks to Matt Benson). It hasn't been released yet, but there are some new examples in the project site, in the trunk of the SVN. I will use one of these examples to show how [functor] functional interfaces can be used in conjunction with Java 8 lambdas.

After the example with [functor] in Java 8, I will explain how I am running Java 8 in Eclipse (it's kind of a gambiarra, but works well).

Running BDD tests from TestLink in Jenkins

Last night and this morning I spent some time working on running BDD tests that were created in TestLink in Jenkins, using testlink-plugin.

Similar integration has already been proposed in JinFeng, by Olivier Renault. Basically, you write BDD stories in TestLink (a story goes into the Test Case summary), Jenkins retrieves these stories and executes them using a skeleton project.

There are many ways to use BDD. In some of them you write code like Java, Ruby or Perl, and in others you write a DSL. I started working with JBehave, but for this integration, I preferred to use a DSL - as TestLink doesn’t maintain source code, only test cases -, so I switched to easyb.

A quick view on Wordpress, Mantis and Jenkins plug-in API

I'm preparing a plug-in API proposal for TestLink, and thought that the best way to learn how to write a good plug-in API would be by looking at other application's plug-in API's.

This post contains information that I gathered for creating this new API, but that may also be useful for other programmers. I used Wordpress, Mantis and Jenkins in this study. Let me know if you find any mistakes or if you have any other suggestions.

Replacing a HashSet with a BitSet

I always read the messages in the Apache dev mailing lists, including Apache Commons dev mailing list. And you should too. There are always interesting discussions. Sometimes you participate, other times you only watch what's happening, but in the end you always learn something new.

A few days ago, I found an issue where it was being proposed to replace an unnecessary HashSet in ArrayUtils#removeElements() by a BitSet. Here's how the code looked like:

Adding coverage reports in Jenkins with GoogleTest and gcovr

After the last post about GoogleTest and TestLink using Jenkins TestLink Plug-in, I received an e-mail asking about coverage with GoogleTest and Jenkins. I’ve just updated the Makefile in the samples directory, of the GoogleTest TAP listener project, to output coverage data.

Basically, you have to add the compiler flags -fprofile-arcs -ftest-coverage and link the executable with -lgcov. Take a look at the project’s Makefile and you’ll notice how simple it is. In order to have Jenkins interpreting your coverage report, you’ll have to convert it to cobertura XML. There is a Python utility that can be used for this: gcovr. Download it and copy it to somewhere where Jenkins can execute it (e.g.: /usr/local/bin).

Now, if you’ve followed the instructions from the previous post, you should have a job that reports your GoogleTest tests from Jenkins to TestLink using the plug-in, and is downloading the source code from GitHub. Add an extra build step (Shell) to execute gcovr.