Homework Assignment 7

A Graphical Bowling Game

810:062
Computer Science II
Object-Oriented Programming

Due: Thursday, March 31, at 8:00 AM

Introduction

First came the BowlingGame, which computes the score of a game and print its scoresheet.

Then came the BallWorld, in which a ball moves about a window on the screen.

Now comes the natural next step in the fantasy that is Computer Science II: BowlingGameWorld.

This assignment gives you an opportunity to create your first graphical program. You may use the various BallWorld, MultiBallWorld, and even CannonGame programs as a starting point, but this program is all your own. Feel free to meet the minimum requirements of the assignment and then add your own personal flourish to your program!

*** Programming Advice

As always, you should write your program in the style we have used all semester long:

• First, write a test that expresses what you would like your code to do.
• Then write the code to do it.
• Finally, refactor your code to improve the design.

Take small steps, and your tests will give you feedback as soon as possible. Use the GenerateTest program to create your test class.

*** Code Base

Use the following code as your starting point:

• the BowlingGame from the Session 9 .zip file
• the MultiBallWorld from the Session 17 .zip file
• the CloseableFrame class, which defines a frame whose "close button" works

New Java

Labels

A Java Label is a component that can be added to a Frame, like a Button. Labels do not give the use a way to give input; they are for displaying text only. You can change a Label's text by sending it a setText() message. Other useful messages include getText() and setAlignment().

You create a Label and add it to a Frame just as yu would a Button, but you don't add a listener to it.

Note: Java Label do not recognize embedded new-line characters, so whatever you display in one will appear on a single line.

Tasks

A BowlingGameWorld has three parts:

1. At the top of the window is text that shows at least the current frame number and the current score of the game.
2. At the bottom of the window is a button that allows the user roll a bowling ball.
3. In the middle of the window is where a bowling ball rolls and "knocks down" some pins.

Here are some more specific ideas about the three primary tasks:

• For the text display, you can add a Label to the top of the window. See the example in New Java section above. You can also send the Graphics object a drawString() message.

• Use a BowlingGame to keep track of the score and any other scoring information you need.

  You may want to add a new public message to the BowlingGame class. Before you do, send me your request first.

• When the user presses the button, we want to see a simulation of a bowling ball rolling across the screen and knocking down some pins. Your program does not have to look like a real bowling game. At this point, your graphics will probably be quite simple. That's okay.

  You don't need to show the shot curving toward the pins. Your bowling ball does not have to "hit" pins in any particular fashion, "bounce off" the pins, or even look like it is "knocking down" any particular pins.

  You may keep it simple. Paint the pins in the right part of screen. When the user presses the button, a new bowling ball appears on the left and moves toward the pins. When it reaches the pin area, you can repaint the screen with the appropriate number of pins gone, and the ball, too.

• Where do the roll values come from? Create a BowlingRollStream object that responds to a nextRoll() message by returning an int. Initialize your BowlingRollStream with a filename. The file will contain a single line containing a legal set of rolls for a complete bowling game, separated by commas. For example, the file might contain:

           5,4,5,4,5,4,5,4,5,4,5,4,5,4,5,4,5,4,5,4
  

  or:

           10,10,10,10,10,10,10,10,10,10,10,10
  

  Each time the user presses the button, the program can send a nextRoll() message to the BowlingRollStream. When the BowlingRollStream runs out of rolls from the file, it returns -1.

• Your BowlingGameFrame should extend CloseableFrame. Its constructor should take a BowlingRollStream as an argument.

• Your BowlingGame driver program must take command-line arguments of the form:

           -f filename
  

  The "-f" is a switch which indicates that the next argument is a filename. The filename is the name of the file that contains the bowling rolls.

  Your BowlingGame should use the filename to create a BowlingRollStream, use the BowlingRollStream to create a BowlingGameFrame, and then show the BowlingGameFrame.

• When the game is over -- that is, when the BowlingRollStream returns -1 -- the frame may just sit there, even if the user presses the button again.

  If you'd like to do something more sophisticated, just run your idea by me first.

At first, focus your attention on creating a good set of objects to implement the program. Once you have a decent set of objects orking together, if you have the time and energy, you may go beyond the simple graphics described above to do something more.

Deliverables

By the due date and time, submit these files:

• BowlingBall.java
• BowlingRollStream.java
• BowlingGameFrame.java
• BowlingGameWorld.java
• any xxxTest.java files you create

Be sure that your submission follows all homework submission requirements.