Answer Happy

JAVA ONLY
I have created an Oval class that demonstrates how to create a
subclass from GeometricShape. I have also recorded a demo
video explaining each piece of the class.
Using the supplied code as your guide, create a Trapezoid class
that has the following:
1. Setters for all private attributes.
2. Getters for all private attributes.
3. A constructor with no parameters. Unlike Oval, have it
call its own constructor with default parameters.
4. A constructor with parameters for all private attributes,
filled, and color.
5. A toString method that overrides GeometricObject’s.
6. A getArea method that returns the area of the
Trapezoid. The area of a trapezoid is .5 * h * (b1 + b2).
Modify the main so that:
7. It creates a Trapezoid object.
8. It adds that object to the shapes list.
9. It prints the Trapezoid and the area in the for
loop.
MAIN
import java.util.ArrayList;
public class Main {
public static void main(String[] args){
ArrayList<GeometricObject>
shapes = new ArrayList<GeometricObject>();
GeometricObject genericShape = new
GeometricObject();
Oval oval = new Oval(10, 15, "blue",
true);
//TODO: Add Trapezoid creation
here
shapes.add(genericShape);
//polymorphism: the type
GeometricObject (that the shapes list contains)
//can refer to a Oval because Oval
is a subclass of GeometricObject
shapes.add(oval);
//TODO: add Trapezoid to shapes
//"foreach element in shapes, call
it shape"
for(GeometricObject shape:
shapes){
System.out.println(shape.toString());
//GeometricShape does
not have a getArea(), so we have to check to
//see what subclass it
is, and then cast appropriately
if( shape instanceof
Oval ){
System.out.println(((Oval)shape).getArea());
}
//TODO: print
trapezoid getArea
System.out.println("======================");
}
}
}
GeometricObject.java
public class GeometricObject {
private String color = "white";
private boolean filled;
private java.util.Date dateCreated;
/** Construct a default geometric object */
public GeometricObject() {
dateCreated = new
java.util.Date();
}
/** Construct a geometric object with the
specified color and filled value */
public GeometricObject(String color, boolean
filled){
dateCreated = new
java.util.Date();
this.color = color;
this.filled = filled;
}
/** Return color */
public String getColor() {
return color;
}
/** Set a new color */
public void setColor(String color) {
this.color = color;
}
/** Return filled. Since filled is boolean,
its getter method is named isFilled */
public boolean isFilled() {
return filled;
}
/** Set a new filled */
public void setFilled(boolean filled) {
this.filled = filled;
}
/** Get dateCreated */
public java.util.Date getDateCreated() {
return dateCreated;
}
/** Return string representation of this object
*/
public String toString() {
return "created on " + dateCreated +
"\ncolor: " + color + " and filled: " + filled;
}
}
Oval.java
ublic class Oval extends GeometricObject {
private double a, b;
public Oval() {
//super() is called here because we
don't specify a super constructor
a = 1;
b = 1;
}
public Oval(double a, double b, String color,
boolean filled) {
super(color, filled); //call super
constructor
this.a = a; //use "this." to
differentiate between parameter and attribute
this.b = b;
}
//getters
public double getA() {
return a;
}
public double getB() {
return b;
}
//setters
public void setA(double a) {
this.a = a;
}
public void setB(double b) {
this.b = b;
}
//methods
public double getArea(){
double area = (a / 2) * (b / 2) *
Math.PI;
return area;
}
//overrided methods
@Override
public String toString(){
//call inherited methods from
GeometricObject
return "Oval: " + a + " " + b + "\n"
+ getColor() + ", " + isFilled();
}
}