CS 257: Software Design

An all-class project: sprites in a box

Phase 3 of 3: Implementing the Sprite

The goals for this final phase of the sprites assignment are:

• Implement a Sprite subclass
• Add your sprite code to our shared repository

What to do

• If you completed Phase 2 successfully, you have been invited to the cs257_sprites bitbucket repository. Go there and clone the repository onto your computer.
• Try compiling SpriteWorld.java. It will fail to compile because of a missing file.
• Make a copy of SpriteWorld.java--maybe MyWorld.java. Edit MyWorld.java to (1) change the name of the class to match the name of the file, and (2) fix it so it can compile with just the files in the repository. Run the resulting program.
• Study Sprite.java to see what the existing methods do, and to identify the methods declared as abstract. That should tell you what your Sprite subclass will need to do.
• Implement a Sprite subclass of your own. Make sure that at minimum, your subclass works with the existing SpriteWorld. But keep in mind that I will test your subclass with an entirely different program. As long as you adhere to the specification described in the comments in Sprite.java, your sprite should work just fine no matter what kind of crazy main program I use to test it.
• Name your Sprite subclass using your user name, starting with a capital letter and using camel case for your initial. For example, my subclass would be called JOndich, while Zebediah Student (with e-mail address studentz, of course) would implement StudentZ, in StudentZ.java.
• Create a subfolder in cs257_sprites, using your Carleton user name.

• Add your sprite class to the cs257_sprites project to your subfolder (e.g. I will put my sprite in cs257_sprites/jondich/JOndich.java). If your sprite uses any support files (e.g. sound or image files), then put them in your subfolder as well. Then:

  • Commit
  • Pull
  • Update (or Merge if hg tells you to merge instead of updating)
  • Push
• Note: you have both read and write access to the repository. Be careful not to mess with other people's sprites.

Notes

• Don't change SpriteWorld.java or Ball.java.. If you were to change either one and then push your changes, other people wouldn't get the original files.
• Really really don't change Sprite.java at all, ever. Sprite.java is the specification for your assignment. If your subclass doesn't work with the existing Sprite as its superclass, then your subclass is not correct. Fix the subclass, not the parent class. (Note that Sprite as it is can't do all sorts of neato things you might want to do. Too bad. Changes to Sprite itself would have to be negotiated with the whole team. You as an individual developer don't have the authority to make that change unilaterally.)
• Code sample for using image files: ImageTest.java and moose.jpeg
• Code sample for using sound files (.wav, .au, and .aiff only): SoundTest.java and moose.wav

Your chance for glory

On Friday, we'll run a test program with all the sprites. I'll pick a Jeff's Choice winner, and we'll have a vote for People's Choice as well. Winners will get an extra 2 points on the assignment, but more importantly, the world-wide acclaim that comes from these prestigious awards.