Question

The java.awt.Rectangle class of the standard Java library does not supply a method
to compute the area or perimeter of a rectangle. Provide a subclass BetterRectangle of the Rectangle class that has getPerimeter and getArea methods. Do not add any instance variables. In the constructor, call the setLocation and setSize methods of the Rectangle class.

In Main class, provide 3 test cases that tests the methods that you supplied printing expected and actual results.

The test cases are: 1) One positive test case testing your method with valid inputs 2) Two negative test cases, testing your methods for invalid inputs and printing proper error message indicating proper error handling.

Answer 1

BetterRectangle.java

import java.awt.Rectangle;

public class BetterRectangle extends Rectangle {
  
   //constructor
   public BetterRectangle(int locx, int locy, int sizex, int sizey) throws Exception{
       //checking if size is less than zero
       if(sizex < 0 || sizey < 0) {
           throw new Exception("Size less than zero\n\n");
       }
      
       //checking if both sizes are zero
       if(sizex == 0 && sizey == 0) {
           throw new Exception("Size is zero\n\n");
       }
       //setting location ans size
       this.setLocation(locx, locy);
       this.setSize(sizex, sizey);
   }
   //calculating area
   public double getArea() {
       return this.getWidth() * this.getHeight();
   }
   //calculating perimeter
   public double getPerimeter() {
       return 2 * (this.getWidth() + this.getHeight());
   }

}

Main.java

public class Main {

   public static void main(String[] args) throws Exception {
       //valid test caes
       BetterRectangle betRec1 = new BetterRectangle(1,1,5,5);
       System.out.println("Perimeter 1 Expected: 20 Actual: " + betRec1.getPerimeter());
       System.out.println("Area 1 Expected: 25 Actual: " + betRec1.getArea() + "\n\n");
      
       BetterRectangle betRec2 = new BetterRectangle(1,1,1,1);
       try {
           //invalid test case with size less than zero
           betRec2 = new BetterRectangle(1,1,-4,5);
          
       }catch(Exception ex) {
           System.out.println("Perimeter 2 Expected: 2 Actual: " + betRec2.getPerimeter());
           System.out.println("Area 2 Expected: -20 Actual: " + betRec2.getArea());
           System.out.println("Error 2:" + ex.getMessage());
          
       }
      
       BetterRectangle betRec3 = new BetterRectangle(1,1,1,1);
       try {
           //invalid test case with size equals 0
           betRec3 = new BetterRectangle(1,1,0,0);
          
       }catch(Exception ex) {
           System.out.println("Perimeter 3 Expected: 0 Actual: " + betRec3.getPerimeter());
           System.out.println("Area 3 Expected: 0 Actual: " + betRec3.getArea());
           System.out.println("Error 3:" + ex.getMessage());
          
       }

   }

}

Sample Output:

Perimeter 1 Expected: 20 Actual: 20.0
Area 1 Expected: 25 Actual: 25.0

Perimeter 2 Expected: 2 Actual: 4.0
Area 2 Expected: -20 Actual: 1.0
Error 2:Size less than zero

Perimeter 3 Expected: 0 Actual: 4.0
Area 3 Expected: 0 Actual: 1.0
Error 3:Size is zero