Instructions: Abstract Superclass Shape and Its Concrete Subclasses Implement the superclass Shape and its subclasses Circle, Rectangle and Square, as shown in the class diagram. Implement Unit Tests for the all classes except the abstract Shape class. In this exercise, Shape shall be defined as an abstract class, which contains: Two protected instance variables color(String) and filled(boolean). The protected variables can be accessed by its subclasses and classes in the same package.
Instructions: Abstract Superclass Shape and Its Concrete Subclasses
Implement the superclass Shape and its subclasses Circle, Rectangle and Square, as shown in the class diagram.
Implement Unit Tests for the all classes except the abstract Shape class.
In this exercise, Shape shall be defined as an abstract class, which contains:
- Two protected instance variables color(String) and filled(boolean). The protected variables can be accessed by its subclasses and classes in the same package. They are denoted with a '#' sign in the class diagram.
- Getter and setter for all the instance variables, and toString().
- Two abstract methods getArea() and getPerimeter() (shown in italics in the class diagram).
The subclasses Circle and Rectangle shall override the abstract methods getArea() and getPerimeter() and provide the proper implementation. They also override the toString().
Run a test class to test these statements involving polymorphism and explain the outputs with comments inside the file "ShapeDriver.java". Some statements may trigger compilation errors. Explain the errors, if any.
Shape s1 = new Circle(5.5, "RED", false); // Upcast Circle to Shape System.out.println(s1); // which version?
System.out.println(s1.getArea()); // which version? System.out.println(s1.getPerimeter()); // which version? System.out.println(s1.getColor()); System.out.println(s1.isFilled()); System.out.println(s1.getRadius());
Circle c1 = (Circle)s1; // Downcast back to Circle
System.out.println(c1);
System.out.println(c1.getArea());
System.out.println(c1.getPerimeter());
System.out.println(c1.getColor());
System.out.println(c1.isFilled());
System.out.println(c1.getRadius());
Shape s2 = new Shape();
Shape s3 = new Rectangle(1.0, 2.0, "RED", false); // Upcast System.out.println(s3);
System.out.println(s3.getArea());
System.out.println(s3.getPerimeter());
System.out.println(s3.getColor());
System.out.println(s3.getLength());
Rectangle r1 = (Rectangle)s3; // downcast System.out.println(r1); System.out.println(r1.getArea());
System.out.println(r1.getColor());
System.out.println(r1.getLength());
Shape s4 = new Square(6.6); // Upcast
System.out.println(s4);
System.out.println(s4.getArea());
System.out.println(s4.getColor());
System.out.println(s4.getSide());
// Take note that we downcast Shape s4 to Rectangle,
// which is a superclass of Square, instead of Square
Rectangle r2 = (Rectangle)s4;
System.out.println(r2);
System.out.println(r2.getArea());
System.out.println(r2.getColor());
System.out.println(r2.getSide());
System.out.println(r2.getLength());
// Downcast Rectangle r2 to Square
Square sq1 = (Square)r2;
System.out.println(sq1);
System.out.println(sq1.getArea());
System.out.println(sq1.getColor());
System.out.println(sq1.getSide());
System.out.println(sq1.getLength());
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