public interface Cake {    public int cost();}

<!-- 装饰蛋糕 -->public abstract class CakeDecorator implements Cake{}

public class AppleCake extends CakeDecorator{    private Cake cake;    public AppleCake(Cake cake) {        this.cake = cake;    }        @Override    public int cost() {        System.out.println("送小蛋糕");        return cake.cost() + 12;    }}

public class MilkCake implements Cake{    @Override    public int cost() {        return 100;    }}

public class Test {    public static void main(String[] args) {                MilkCake mc = new MilkCake();                AppleCake ac = new AppleCake(mc);                OrangeCake oc = new OrangeCake(ac);                //OrangeCake oc = new OrangeCake(new AppleCake(new MilkCake()));                System.out.println(oc.cost());            }}