Ant Code Katas

Build systems allow multiple developers on different platforms to coordinate work on a project with relative ease. Though I am by myself a single developer, I anticipate that I will have to work with others on projects in the future, and in any event becoming familiar with build systems should serve as a useful experience. For the moment, I am working in Ant (discussed in more detail at http://ant.apache.org ), which as I understand is the standard build system for Java applications. To familiarize myself with Ant, I have worked on eight Ant katas, similar in purpose to the Robocode Code Katas that I completed a little over a week ago.

1: Ant Hello World: Prints “Hello World.”
2: Ant Immutable Properties: Demonstrates the immutability of build properties; once defined, the value of a property cannot change.
3: Ant Dependencies: Shows how targets depend on one another.
4: Hello Ant Compilation: Compiles a file HelloAnt.java from a src directory and creates a build/classes directory for the class file to be placed into.
5: Hello Ant Execution: Runs the compiled HelloAnt program.
6: Hello Ant Documentation: Generates the JavaDocs for the HelloAnt program.
7: Cleaning Hello Ant: Adds a “clean” target to the compilation kata that removes the build directory.
8: Packaging Hello Ant: Creates a zip file containing the Ant katas and the source code for HelloAnt.

All eight of these katas were completed successfully, though as with the Robocode katas some difficulties became apparent only as I worked on the programming. Ant uses XML files, and though I have a passing familiarity with XML structure I have never actually written anything in XML for at least a few years. Fortunately these katas are relatively simple, and since Ant has its own keywords I did not have to learn XML and Ant simultaneously.

The main difficulty that I had in completing these katas was with Kata 5, in which I had to execute the HelloAnt program. The java task in Ant can take either a .jar or a class file as the file to run. Given that the kata preceding this compiled HelloAnt.java into a class file, I felt that using the class file was the more logical choice. However, the vast majority of the examples available on the Internet use .jar files with java.

This lack of examples led to the next problem. Kata 5 originally worked as intended, running the Java program without errors. However, when working on Kata 6, I realized that I had forgotten to specify the package that HelloAnt.java should be in. Fixing this was simple enough, and soon Kata 6 was working. Unfortunately, when I got to Kata 8, which required that everything in HelloAnt work perfectly, the code from Kata 5 began to produce errors. Specifically, Java could not find the HelloAnt.class file. After some investigation, I understood that the error had something to do with the package but could not find a solution; even specifying the exact folder that the file was in for the class path did not work. None of the resources online offered any substantive advice. It was not until much later, when I asked a classmate about the matter, that I learned that the class name for the java task had to be fully qualified. This resolved the problem immediately.

I understand why Ant would do this. After all, there could be classes in different packages with the same name, in which case the best and possibly only way to tell them apart might well be the package. At the same time, I cannot help but think that a system should be able to recognize that a file with the same name and in a series of folders that matches the package structure of the file that it is searching for could actually be the file that it is searching for.

Overall, the katas were not terribly difficult. The problem with the class name was the only significant delay in completing the katas, even if that one problem was severely stressful. Aside from that issue, there were only the usual problems with trying to learn what is essentially a new language for me. I do not consider myself fluent in Ant yet, but I can at least use Ant and write files that Ant can use, if with the occasional need to look through some reference source.

I learned a great deal about Ant from completing these katas. However, perhaps more importantly, I was reminded of the value of human sources of information. Most of the times when I want to learn something, I look on the Internet or in a book. Humans though serve as a source that can account for context and focus on relevant details. Although I still prefer written sources of information, I will have to remember that humans such as my classmates are still valid sources as well.