《Head First 设计模式》装饰者模式_head first 设计模式装饰者代码-优快云博客

本文链接：https://blog.youkuaiyun.com/macmouse/article/details/21076173

本文介绍了一种不使用继承而扩展对象功能的方法——装饰者模式，并通过一个咖啡订购系统的实例展示了如何动态地为对象添加职责。该模式允许在运行时通过装饰来扩展对象的功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

装饰者模式：动态的将责任附加到对象上。想要扩展功能，装饰者提供有别于继承的另一种选择。

package headfirst.decorator.starbuzz;

public class DarkRoast extends Beverage {
	public DarkRoast() {
		description = "Dark Roast Coffee";
	}
 
	public double cost() {
		return .99;
	}
}

package headfirst.decorator.starbuzz;

public class Mocha extends CondimentDecorator {
	Beverage beverage;
 
	public Mocha(Beverage beverage) {
		this.beverage = beverage;
	}
 
	public String getDescription() {
		return beverage.getDescription() + ", Mocha";
	}
 
	public double cost() {
		return .20 + beverage.cost();
	}
}

package headfirst.decorator.starbuzz;

public class StarbuzzCoffee {
 
	public static void main(String args[]) {
		Beverage beverage = new Espresso();
		System.out.println(beverage.getDescription() 
				+ " $" + beverage.cost());
 
		Beverage beverage2 = new DarkRoast();
		beverage2 = new Mocha(beverage2);
		beverage2 = new Mocha(beverage2);
		beverage2 = new Whip(beverage2);
		System.out.println(beverage2.getDescription() 
				+ " $" + beverage2.cost());
 
		Beverage beverage3 = new HouseBlend();
		beverage3 = new Soy(beverage3);
		beverage3 = new Mocha(beverage3);
		beverage3 = new Whip(beverage3);
		System.out.println(beverage3.getDescription() 
				+ " $" + beverage3.cost());
	}
}