Decorator pattern from AP 2015 Simon's example

Decorator pattern.java

// the first step is to define an abstract 
// class that both BasicCar and our decorators will extend

public abstract class Car {
	public abstract double getPrice();
	public abstract String getDescription();
}

public class BasicCar extends Car{
	public double getPrice() {
		return 10000;
	}
	public String getDescription() {
		return "The basic car";
	}
}

// Decorators will add functionality to this
// by implementing these methods slightly differently
public abstract CarDecorator extends Car {

	protected Car decoratedCar;
	public CarDecorator(Car decoratedCar) {
		this.decoratedCar = decoratedCar;
	}

	public double getPrice() {
		return decoratedCar.getPrice();
	}

	public String getDescription() {
		return decoratedCar.getDescription();
	}
}

// add Alloys to the basic car
public class AlloyDecorator extends CarDecorator {
	public AlloyDecorator(Car decoratedCar){
		super(decoratedCar);
	}

	public Double getPrice() {
		return super.getPrice() + 250;
	}
	
	public String getDescription() {
		return super.getDescription() + " + Alloys";
	}
}

// add CD Player to the basic car
public class CDDecorator extends CarDecorator {
	public CDDecorator (Car decoratedCar) {
		super(decoratedCar);
	}

	public Double getPrice() {
		return super.getPrice() + 150;
	}

	public String getDescription() {
		return super.getDescription() + " + CD Player"
	}
}

public class DecoratorTest {
	public static void main(String args) {

		Car base = new BasicCar();
		System.out.println("Car costs " + base.getPrice() + " and has " + base.getDescription());

		Car alloys = new AlloyDecorator(new BasicCar());
		System.out.println("Car cost " + alloys.getPrice() + " and has " + alloys.getDescription());

		Car cd = new CDDecorator(new BasicCar());
		System.out.println("Car costs " + cd.getPrice() + " and has " + cd.getDescription());

		Car all = new CDDecorator(new AlloyDecorator (new BasicCar()));
		System.out.println("Car costs " + all.getPrice() + " and has " + cd.getDescription());
	}
}