CSE115 Fall 2007 - Lab #6

Working from home

If you are working from home you must download a current copy of the Classlibs.jar file
WINDOWS: download and place in your C:\projects\CSE115\Classlibs\Fall2007 directory
OS X/Linux/Unix/etc: download and place in your /projects/CSE115/Classlibs/Fall2007 directory

Introduction

Objectives

• define a class which implements an interface
• implement an interface in different ways
• work more independently in solving a programming task than in past labs

Lab Design

In this lab you will define a number of classes whose instances appear as circles and squares. They are to move around in a window in different ways. You will, in how you define these classes, specify their behaviors. Your TA will show you a demo of one possible solution.

In order for the classes that you define to work with the graphical framework that we have set up for you, they must implement the IUpdatable interface:

package lab6lib;

/**
 * An IUpdatable is an object which can be updated.
 * 
 * Created: Oct 2007
 * 
 * @author Carl Alphonce
 */

public interface IUpdatable {

    /**
     * Update the object in whatever way you want.
     */
    public void update();
}

Of course nothing worth doing is as easy as we'd like. In addition to implementing the IUpdatable interface, each class that you define must have (in the sense of the composition relationship) an lab6lib.IGraphic, which will serve as its graphical representation. IGraphic is an interface, so you can't instantiate it. However, you don't need to define classes which implement it, because we have already done that: the two classes lab6lib.CircleGraphic and lab6lib.SquareGraphic implemenet lab6lib.IGraphic.

Since these two classes implement the lab6lib.IGraphic interface, they provide the following method definitions:

package lab6lib;

/**
 * An IGraphic is a graphic whose color, location, dimension and orientation
 * properties can be queried and set.
 * 
 * Created: Sun Oct 10, 2003
 * 
 * @author Carl Alphonce
 * 
 */

public interface IGraphic {

    /**
     * Sets the color of this IGraphic.
     * @param c - the new color
     */
    public void setColor(java.awt.Color c);

    /**
     * @return the current color of this IGraphic
     */
    public java.awt.Color getColor();

    /**
     * Sets the location of this IGraphic.
     * @param p - the new location
     */
    public void setLocation(java.awt.Point p);

    /**
     * @return the current location of this IGraphic
     */
    public java.awt.Point getLocation();

    /**
     * Sets the dimension of this IGraphic.
     * @param d - the new dimension
     */
    public void setDimension(java.awt.Dimension d);

    /**
     * @return the current dimension of this IGraphic
     */
    public java.awt.Dimension getDimension();

    /**
     * Sets the orientation (rotation) of this IGraphic.
     * @param d - the new orientation, in degrees
     */
    public void setOrientation(lab6lib.Degree d);

    /**
     * @return the current orientation (rotation) of this IGraphic, in degrees
     */
    public lab6lib.Degree getOrientation();
    
    /**
     * Make the IGraphic move.
     */
    public void move();
}

To help you get started, here's a skeletal class definition along the lines of what you're aiming for:

package lab6;

public class MyExample implements IUpdatable
{
   private IGraphic _graphic;

   public TurningSquare (lab6lib.Window w) {
	   _graphic = new lab6lib.SquareGraphic(w);
   }

   public void update() {
	   _graphic.move();
   }

}

1. The constructor for both lab6lib.SquareGraphic and lab6lib.CircleGraphic takes a lab6lib.Window as an argument.
2. In the update method you will define the class' behavior...but don't forget to call move() on the IGraphic, otherwise it will just sit in the same position in the window.