/**
 * Abstract geometrical shape that intrinsically knows how to compute its area.
 * Concrete methods to compute areas are relegated to concrete implementations.
 * @author Dung X. Nguyen
 * @Copyright 2002 by Dung X. Nguyen - All rights reserved.
 */
public interface IShape {
    /**
     * For concrete implementations to provide code to compute the area.
     * @return this IShape's area.
     */
    public double getArea();
}