Decorator pattern

import java.util.*;

abstract class BasePizza{
    public abstract int cost();
}

class Farmhouse extends BasePizza{
    public int cost(){
        return 100;
    }
}

// is a realtionship
abstract class ToppingDecorator extends BasePizza{
}

class ExtraCheese extends ToppingDecorator{
    // has a relationship
    BasePizza basePizza;
    ExtraCheese(BasePizza basePizza){
        this.basePizza = basePizza;
    }
    public int cost(){
        return this.basePizza.cost()+10;
    }
}
public class Main{
    public static void main(String args[]){
        BasePizza pizza1 = new ExtraCheese(new Farmhouse());
        System.out.println(pizza1.cost());

    }
}