Week 2, Friday

April 3, 2009 at 8:09 pm (Java, System Administration, Week 2) (, , , , , , )

Time is flying a lot faster now. Today I looked at some new technologies (new to me, anyway): Ant and the KML API for Google Maps.

For Rubyists out there, Ant is analogous to Rake, but in the Java world (and Make for C/C++/others). It’s kind of an automated build tool, so that you can avoid duplicating labor each time you want to build a project and run the test suite (or any number of other things). Micah wanted me to build an Ant task that would run all of my tests. So I checked out the Ant manual, but it wasn’t much help at all to me until I’d seen and worked my way through a concrete example. It’s pretty nifty – until now, as far as I knew, I’d have to either let IntelliJ run the tests for me or go through each test class manually running the JUnit tests.

I also had to fix my directory structure to make it more idiomatic for a Java project. Previously I just had my src directory with all my *.java files under version control, but it turned out that what I really needed was to go up a directory and have the main project under version control (Git). This presented a problem for me in that if I just moved my .git directory up to the main project directory, it would appear to Git that I’d deleted and re-added a bunch of files, which would mean that every file’s history would begin again, and I’d lose the ability to see small changes from the previous commit to the next one (just for a certain commit, but still, I didn’t like it). Here’s the workflow I used to move Git’s notion of the structure up a directory, in case anybody else runs into the same issue:

  1. mkdir src/src
    because I knew I was going to need to see the current source files in an src directory, but it needed to be relative to the current Git location, src
  2. git mv src/*.java src/src
    here’s where I’m telling Git to rename the files – the key action that allowed me to preserve history on the same file
  3. mv src/src src_new
    moving the actual source files up to a new folder in the root (which is going to be src eventually, but since “src” is taken for now…
  4. mv src/.git .
    one of the many cool things about Git is that ALL of the versioning information is contained in a single directory – no .svn directories littering the project and making change like this difficult
  5. mv src src_old
    making way for the new src directory
  6. mv src_new src
    in place the way we need it
  7. git status
    checking to make sure things look good, with files being renamed instead of added and deleted)

Pretty simple, considering my initial worries. Thanks, Git!

My time with KML so far has been pretty educational, but I haven’t actually gotten anything done yet, I’ve just been investigating options. I’m working on a problem where I have points on a map with identical latitudes and longitudes, and I need to tell Google Maps to display them as separate points somehow. I’ve found a way to make Google Earth do it fine, but Google Maps is a different story.

Another task I’ve got before I get going on 3-D Tic-Tac-Toe is to split my 2-D version into packages. So I’m going to bone up on the package principles this weekend. I have a tentative separation already (there was some Git love that needed to happen there, too, when I moved files around), but I know have some Common Closure Principle violations I need to take care of before daring to show it to Micah.

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1 Comment

  1. Paul Pagel said,

    “For Rubyists out there, Ant is analogous to Rake, but in the Java world (and Make for C/C++/others)”

    I like that order. Follows reverse history and ease of use.

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