Shapes Package

The Shapes package demonstrates how interfaces can be extended and implemented in Java to create a flexible and modular object-oriented design. This package consists of multiple sub-packages containing interfaces and classes that model various geometric shapes.

Interface Extension in Java

In Java, interfaces can extend other interfaces, allowing for hierarchical relationships that enable more structured and reusable designs. This approach promotes abstraction and ensures that classes implementing these interfaces conform to specific behaviors.

Overview of Interface Relationships

• IShape: A base interface representing any geometric shape.
• IPolygon: Extends IShape, representing polygonal shapes.
• IRegularPolygon: Extends IPolygon, adding constraints for regular polygons.
• ITriangle: Extends IPolygon, providing a default method getNumberOfSides() that returns 3.
• IEllipse: Extends IShape, representing elliptical shapes.
• ICircle: Extends IEllipse, representing circles.
• IRectangle: Extends IPolygon, representing rectangles. It also provides a default method getNumberOfSides() that returns 4. This implies class Square and Rectangle will provide 4 when getNumberOfSides() is called for these classes. Both classes inheriting it from the IRectangle interface.

Overview of Implementations

• EqTriangle: Implements both IRegularPolygon and ITriangle, demonstrating multiple interface implementations.
• Circle: Implements ICircle, demonstrating how circles conform to the elliptical shape hierarchy.
• Rectangle: Implements IRectangle, modeling general rectangles.
• Square: Extends Rectangle and implements IRegularPolygon, allowing squares to inherit rectangle properties while conforming to the regular polygon constraints.

This structure demonstrates the power of interface extension, enabling shared behavior while allowing specific characteristics to be defined for each shape type.