FactoryPattern

Application.java

public class Application {

    public static void main(String[] args) {
        ShapeFactory shapeFactory = new ShapeFactory();

        Shape shape1 = shapeFactory.getShape("CIRCLE");
        shape1.draw();
        // Output: Wow! you drawed a circle.

        Shape shape2 = shapeFactory.getShape("RECTANGLE");
        shape2.draw();
        // Output: Wow. you drawed a rectangle.

        Shape shape3 = shapeFactory.getShape("SQUARE");
        shape3.draw();
        // Output: Wow. you drawed a square.
    }

}

Circle.java

public class Circle implements Shape {

    @Override
    public void draw() {
        System.out.println("Wow! you drawed a circle.");
    }

}

Rectangle.java

public class Rectangle implements Shape {

    @Override
    public void draw() {
        System.out.println("Wow. you drawed a rectangle.");
    }

}

Shape.java

public interface Shape {

    void draw();

}

ShapeFactory.java

public class ShapeFactory {

    public Shape getShape(String shapeType) {
        if (shapeType == null)
            return null;

        if (shapeType.equalsIgnoreCase("CIRCLE")) {
            return new Circle();
        } else if (shapeType.equalsIgnoreCase("RECTANGLE")) {
            return new Rectangle();
        } else if (shapeType.equalsIgnoreCase("SQUARE")) {
            return new Square();
        }

        return null;
    }

}

Square.java

public class Square implements Shape {

    @Override
    public void draw() {
        System.out.println("Wow. you drawed a square.");
    }

}