polymorphism in JAVA eclipse

Admin Posts : 145 Join date : 2011-08-01

polymorphism, exampled via the shape class, and its overridden surface area methode,
in the Main class.

shape super class :

Code:: package com.shapes.objects;

public class Shape {

public Shape() {
// TODO Auto-generated constructor stub
}
public double surfaceArea() {
return 0;
}
}

square sub class of shape

Code:: package com.shapes.objects;

public class Square extends Shape {
private double height;

public double getHeight() {
   return height;
}

public void setHeight(double height) {
   this.height = height;
}
public Square(double height) {
   this.height = height;
}
public double surfaceArea() {
   return height*height;
}
}

rectangle sub class of square

Code:: package com.shapes.objects;

public class Rectangle extends Square{
private double width;

public double getWidth() {
   return width;
}

public void setWidth(double width) {
   this.width = width;
}

public Rectangle(double height, double width) {
   super(height);
   this.width = width;
}
@Override
public double surfaceArea() {
   return super.getHeight()*width;
}

}

triangle sub class of shape

Code:: package com.shapes.objects;

public class Triangle extends Shape {
private double height;
private double width;

public Triangle(double height, double width) {
   super();
   this.height = height;
   this.width = width;
}
public double getHeight() {
   return height;
}
public void setHeight(double height) {
   this.height = height;
}
public double getWidth() {
   return width;
}
public void setWidth(double width) {
   this.width = width;
}
@Override
public double surfaceArea() {
   return (height*width)/2;
}

}

circle class extends (sub class of) shape super class:

Code:: package com.shapes.objects;

public class Circle extends Shape {
private double Radius;
public double getRadius() {
   return Radius;
}
public void setRadius(double radius) {
   Radius = radius;
}

public Circle(double radius) {
   super();
   Radius = radius;
}
public double surfaceArea() {
   return Radius*Radius*3.1415;
}
}

main class plays around with the classes using polymorphism to refer to all objects as a shape
and using the override methods of the sub classes even though they were declared as the super class :

Code:: package com.shapes.objects;

import java.util.Scanner;

import org.w3c.dom.css.Rect;

public class Main {

public static void main(String[] args) {
   // TODO Auto-generated method stub
   Shape sh1 = new Shape();
   System.out.println(sh1.surfaceArea());
   Rectangle rec1 = new Rectangle(10, 5);
   System.out.println(rec1.surfaceArea());
   Shape sh2 = rec1;
   System.out.println(sh2.surfaceArea());

   Shape[] shapeArray = new Shape[5];

   for (int i = 0; i < shapeArray.length; i++) {
      System.out.println("enter shape");
      Scanner scanner2 = new Scanner(System.in);
      String x2 = scanner2.next();
      shapeArray[i] = getShape(x2);
      System.out.println(shapeArray[i].surfaceArea());
   }
}
public static Shape getShape(String form) {
   Shape result = null;
   Scanner scanner11 = new Scanner(System.in);
   switch (form) {
   case "square":
      System.out.println("enter square side size");
      double x1 = scanner11.nextDouble();
      return new Square(x1);
   case "circle":
      System.out.println("enter circle radius");
      double Radius1 = scanner11.nextDouble();
      return new Circle(Radius1);
   case "rectangle":
      System.out.println("enter rectangle height");
      double height = scanner11.nextDouble();
      System.out.println("enter rectangle width");
      double width = scanner11.nextDouble();
      return new Rectangle(height, width);
   case "triangle":
      System.out.println("enter triangle height");
      double Theight = scanner11.nextDouble();
      System.out.println("enter triangle width");
      double Twidth = scanner11.nextDouble();
      return new Triangle(Theight, Twidth);
   default:
      break;
   }
   return result;
}

}

_________________
kurayami no kagi admin