抽象商品類

/**
 * 商品
 */
public abstract class AbstractGoods {

    public abstract String getName() ;

    public abstract Double getPrice();

}

抽象裝飾者包裝類

/**
 * 抽象裝飾者包裝類
 */
public abstract class AbstractGoodsDecorator extends AbstractGoods{

    private AbstractGoods abstractGoods;

    public AbstractGoodsDecorator(AbstractGoods abstractGoods){
        this.abstractGoods = abstractGoods;
    }

    @Override
    public String getName() {
        return this.abstractGoods.getName();
    }

    @Override
    public Double getPrice() {
        return this.abstractGoods.getPrice();
    }
}
 

實體商品類

/**
 * 實體商品類
 */
public class Goods extends AbstractGoods {
    @Override
    public String getName() {
        return "商品清單=";
    }

    @Override
    public Double getPrice() {
        return 0.0;
    }
}

實體商品：蛋糕裝飾者類

/**
 * 蛋糕
 */
public class TakeDecorator extends AbstractGoodsDecorator {

    public TakeDecorator(AbstractGoods abstractGoods) {
        super(abstractGoods);
    }

    @Override
    public String getName() {
        return super.getName() + " 蛋糕";
    }

    @Override
    public Double getPrice() {
        return super.getPrice() + 4.98;
    }
}
 

實體商品：水裝飾者類

/**
 * 水
 */
public class WaterDecorator extends AbstractGoodsDecorator {
    public WaterDecorator(AbstractGoods abstractGoods) {
        super(abstractGoods);
    }

    @Override
    public String getName() {
        return super.getName() + " 水";
    }

    @Override
    public Double getPrice() {
        return super.getPrice() + 2.5;
    }
}
 

呼叫

public class Main {
    public static void main(String[] args) {
        AbstractGoods abstractGoods;
        // 商品清單
        abstractGoods = new Goods();
        // 蛋糕
        abstractGoods = new TakeDecorator(abstractGoods);
        // 水
        abstractGoods = new WaterDecorator(abstractGoods);
        // 水
        abstractGoods = new WaterDecorator(abstractGoods);
        System.out.println(abstractGoods.getName() + " 總價：" + abstractGoods.getPrice());
    }
}

執行結果

商品清單= 蛋糕 水 水 總價：9.98