Rules of the game

• The snake starts at the center of the board, moving north (upward).
• The snake moves at a constant speed.
• The snake moves only north, south, east, or west (ignore the versions of the game where the snake can move in curves).
• The snake "moves" by adding a square to its head and simultaneously deleting a square from the tip of its tail.
• "Apples" appear at random locations, and persist for a random amount of time (but usually long enough for it to be possible for the snake to get to the apple).
• There is always exactly one apple visible at any given time.
• When the snake "eats" (runs into) an apple, it gets longer.
• (This is hard to describe, so play a couple of games to see what I mean.) When the snake gets longer, say by n squares, it does so by not deleting squares from its tail for the next n moves.
• The game continues until the snake "dies".
• A snake dies by either (1) running into the edge of the board, or (2) by running into its own tail.
• The final score is based on the number of apples eaten by the snake.

The snake can be controlled by the arrow keys. (You can use additional keysets if you like, but use at least these.) There should also be a way to pause/resume the game (usually the "P" key).

High scores

The player's score should be based on the number of apples eaten (or equivalently, the length of the snake). The exact scoring algorithm is up to you; most games award more points for each apple as the snake gets longer.

Keep the ten highest scores, along with the names of the players who made those scores. The scores should be kept across all runs of the game. That is, they should not be lost when the program ends.

Keeping (and displaying) high scores isn't as "glamorous" as writing the game itself, but it is harder than you might expect (and more generally useful).

Requirements

Name your project SnakeGame, your package snake, and your "main" class SnakeGame.

Write a "model" class for the game itself. Thoroughly JUnit test this class.

Provide a "hidden" extra-slow mode (but tell us how to find it) so that we can test your program without having to be really good at it.

Write a "model" class for keeping track of high scores. Thoroughly JUnit test this class.

Keeping high scores must be automatic; the user shouldn't have to explicitly say to "Save" them.

A High Scores window should be displayed whenever the player attains a score in the top ten. Additionally, provide a way to see the High Scores window any time that a game isn't actually in progress.

The model classes should do no input/output.

One partner should do the game model, its JUnit tests, and the game GUI. The other partner should do the high scores model, its JUnit tests, and the High Scores GUI. (If you have no partner, you can omit keeping track of the high scores.) Be sure to use @author tags in your classes.

Generate complete Javadoc documentation files for your program, review them, and hand them in as part of the complete package.

Programming notes

You can attach a KeyListener to your JPanel. Here's how you recognize arrow keys.

   public void keyPressed(KeyEvent evt) { 

      int key = evt.getKeyCode();  // Keyboard code for the pressed key.

      if (key == KeyEvent.VK_LEFT) {

          ...

      }

      else if (key == KeyEvent.VK_RIGHT)  {

          ...

      }

      else if (key == KeyEvent.VK_UP) {

          ...

      }

      else if (key == KeyEvent.VK_DOWN) {

          ...

      }

   }

High scores must be kept across different runs of the program. You can do this is by keeping them on a file that you read in at the start of the game, and write out again whenever a high score is achieved.

Optional: If you would like an even better way of keeping high scores (and simpler, once you learn how to use it), see java.util.prefs.Preferences.