Prototype pattern : Example

Example

Dynamic loading is a typical object-oriented feature and prototype example. For example, overriding method is a kind of prototype pattern.

interface Shape {

   public void draw();

}

class Line implements Shape {

   public void draw() {

       System.out.println("line");

   }

}

class Square implements Shape {

   public void draw() {

       System.out.println("square");

   }

}

class Circle implements Shape {

   public void draw() {

       System.out.println("circle");

   }

}

We can code the paint method in the following way:

static void paint(Shape s) { 

  if ( s instanceof Line)

        s.draw();

        //more job here

  if (s instanceof Square)

        s.draw();

        //more job here

  if (s instanceof Circle)

        s.draw();

        //more job here

}