Refactoring Ball'java

1
Session 27

• Refactoring Ball.java
• CannonGame

2
Refactoring Ball into three classes

• Ball.java
• Knows color, position, size, etc (very similar to
  the Circle.java class you are writing in HW6)
• MoveableBall.java
• Extends Ball
• Is responsible for all actions pertaining to
  motion
• BoundedBall.java
• Worries about staying in bounds
• (Version 4)

3
Activity

• What color is the cannon ball?
• What is the role of dy()?
• How does the CannonGame draw the cannon?
• What do lv, lh, sv, and sh mean? What about sx
  and sy?
• How does the cannon ball follow the prescribed
  angle, when we dont pass the angle to the cannon
  ball?
• How does the cannon ball reverse direction?
• How does the game know that the ball has hit
  something (either the target or the floor)?
• How does the program terminate?

4
The CannonGame Application

• Lets go to the tape, Jim