Polymorphism

Circle.java

import java.awt.Graphics;



public class Circle extends Shape {
	int x;
	int y;
	int width;
	int height;
	
	/**
	 * Create a circle object
	 * @param x Top left x position
	 * @param y Top left y position
	 * @param width Width
	 * @param height Height
	 */
	public Circle(int x, int y, int width, int height){
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
	}
	
	@Override
	public void draw(Graphics g, boolean fill){
		if (fill){
			g.fillOval(x, y, width, height);
		}else {
			g.drawOval(x, y, width, height);
		}
		
	}
}

IsoscelesTriangle.java

import java.awt.Graphics;
import java.awt.Polygon;



public class IsoscelesTriangle extends Shape {
	private Polygon triangle;
	
	/**
	 * Create an Isosceles Triangle object
	 * @param x Top x position
	 * @param y Top y position
	 * @param base Length of the base of the triangle
	 * @param height Height of the triangle
	 */
	public IsoscelesTriangle(int x, int y, int base, int height){
		triangle = new Polygon();
		triangle.addPoint(x, y);
		triangle.addPoint( ( x - ( base / 2 ) ), ( y + height ) );
		triangle.addPoint( ( x + ( base / 2 ) ), ( y + height ) );
	}
	
	public void draw(Graphics g, boolean fill){
		if (fill) {
			g.fillPolygon(triangle);
		}else {
			g.drawPolygon(triangle);
		}
	}
}

Main.java

import java.awt.Color;
import java.awt.Graphics;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JApplet;


@SuppressWarnings("serial")
public class Main extends JApplet {
	private List<Shape> shapes = new ArrayList<Shape>();
	
	public void init(){
		// Create Shapes
		Shape square = new Square(5, 5, 50,50);
		Shape circle = new Circle(100,5,50,50); 
		Shape triangle = new IsoscelesTriangle(70,50,100,50);
		
		// Create Triforce
		Shape triforce = new Triforce(200, 200, 100, 50);
		triforce.setShapeColor(Color.YELLOW);
		
		// Add shapes to arrayList
		shapes.add(triangle);
		shapes.add(square);
		shapes.add(circle);
		shapes.add(triforce);
		
	}
	
	@Override
	public void paint(Graphics g){
		// Set Color and draw background 
		g.setColor(Color.BLACK);
		g.fillRect(0, 0, getWidth(), getHeight());
		
		// Draw every shape in the arrayList
		// Polymorphism: The same message call ( .draw ) executes different code depending on the child type 
		for(Shape s: shapes){
			g.setColor(s.shapeColor);
			s.draw(g,false);
		}
	}
}

Shape.java

import java.awt.Color;
import java.awt.Graphics;



public class Shape {
	
	// Default shape color
	protected Color shapeColor = Color.WHITE;
	
	// Change the default shape color
	public void setShapeColor(Color c){
		this.shapeColor = c;
	}

	/**
	 * Method to be overridden by each child class
	 * @param g Graphics object to be passed in from JApplet paint
	 * @param fill Fill in the object?
	 */
	public void draw(Graphics g, boolean fill){
	
	}
	


	
	
}

Square.java

import java.awt.Graphics;


public class Square extends Shape {
	int x;
	int y;
	int width;
	int height;
	
	/**
	 * Create a square object
	 * @param x Top left x position
	 * @param y Top left y position
	 * @param width Width
	 * @param height Height
	 */
	public Square(int x, int y, int width, int height){
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
		
	}

	
	@Override
	public void draw(Graphics g, boolean fill){
		if (fill){
			g.fillRect(x, y, width, height);
		}else {
			g.drawRect(x, y, width, height);
		}
		
	}
}

Triforce.java

import java.awt.Graphics;


public class Triforce extends Shape {
	Shape triangle1;
	Shape triangle2;
	Shape triangle3;
	
	/**
	 * Create a triforce object
	 * @param x Top x position of the top triangle
	 * @param y Top y position of the top triangle
	 * @param base Length of the base of each individual triangle
	 * @param height Height of each individual triangle
	 */
	public Triforce(int x, int y, int base, int height){
		triangle1 = new IsoscelesTriangle(x,y,base,height);
		triangle2 = new IsoscelesTriangle(x-(base/2),y+height,base,height);
		triangle3 = new IsoscelesTriangle(x+(base/2),y+height,base,height);
	}
	
	// When drawing a triforce object always fill in the triangles
	@Override
	public void draw (Graphics g, boolean fill){
		triangle1.draw(g,true);
		triangle2.draw(g,true);
		triangle3.draw(g,true);
	}
}