CSC 172
Homework 7

Assigned 4 Dec, due 13 Dec

• Before you start coding, fill out an estimate form in PSP.

As you go, maintain a log of kinds and numbers of defects, and time spent in various phases of programming. When you're done (or along the way, if you prefer), enter these into the on-line PSP forms.
• For all the programming assignments, be sure to follow the design recipe. Each method should be documented, and each concrete class (and perhaps some abstract classes) should have a test method providing a good test suite for the class. Choose meaningful names for methods and parameters, and watch for opportunities to use methods you've already written. Be sure to test your program thoroughly before turning it in. If it doesn't work, tell me when and how it doesn't work, and what you've tried in attempting to solve the problem.
• Write an Applet that draws a number of colored shapes (e.g. round balls and square boxes) on the screen and moves them around.
  • Distinguish clearly among the model (the shapes and their numeric properties), the view (in charge of how the shapes are drawn on the screen), and the controller (in charge of the dynamic user interface -- what happens in response to what user actions).
  • Implement some kind of list data structure (either roll-your-own or using Java's built-in collection classes) so you can handle as many shapes as the user wants.
  • Provide a "new shape" button (or perhaps two, "new ball" and "new box") that creates a new shape in addition to the ones already on the screen. You may initialize its location and velocity with fixed numbers, or (more fun) randomly.
  • Provide a "delete shape" button that deletes one of the existing shapes. Your program may choose which shape to delete, e.g. the oldest or the newest, or for extra credit you can allow the user to select which shape to delete by clicking on it with the mouse.
  • Provide a "move" button that moves all of the existing shapes as appropriate; note that each shape should have its own velocity. For extra credit, implement a Thread-based timer that moves all the shapes every second (or every five seconds, or whatever you prefer).
  • When a shape reaches the edge of the screen, it should bounce back: if it hits the right or left edge, its X velocity should be negated, and if it hits the top or bottom edge, its Y velocity should be negated.
  • For extra credit, implement not one view but two: the GraphicView shows all the shapes as geometric figures moving around a Canvas, while the TableView (say, running down the right-hand side of the screen) provides a text list of them with types, velocities, and locations. Both views should be automatically updated every time the shapes move. Ideally, it should be possible for the user to select an object by mouse-clicking on it in either view.

  For convenience, here's a link to the on-line Java API documentation.