编辑“︁Java装饰模式”︁（章节）

== 代码示例 ==  
以下是一个模拟咖啡订单系统的示例，展示如何通过装饰模式动态添加配料（如牛奶、糖）的价格和描述。  

=== 基础组件 ===  
<syntaxhighlight lang="java">  
// 抽象组件  
public interface Coffee {  
    double getCost();  
    String getDescription();  
}  

// 具体组件  
public class SimpleCoffee implements Coffee {  
    @Override  
    public double getCost() {  
        return 2.0; // 基础咖啡价格  
    }  

    @Override  
    public String getDescription() {  
        return "Simple coffee";  
    }  
}  
</syntaxhighlight>  

=== 装饰器实现 ===  
<syntaxhighlight lang="java">  
// 抽象装饰器  
public abstract class CoffeeDecorator implements Coffee {  
    protected Coffee decoratedCoffee;  

    public CoffeeDecorator(Coffee coffee) {  
        this.decoratedCoffee = coffee;  
    }  

    @Override  
    public double getCost() {  
        return decoratedCoffee.getCost();  
    }  

    @Override  
    public String getDescription() {  
        return decoratedCoffee.getDescription();  
    }  
}  

// 具体装饰器：牛奶  
public class MilkDecorator extends CoffeeDecorator {  
    public MilkDecorator(Coffee coffee) {  
        super(coffee);  
    }  

    @Override  
    public double getCost() {  
        return super.getCost() + 0.5; // 增加牛奶价格  
    }  

    @Override  
    public String getDescription() {  
        return super.getDescription() + ", with milk";  
    }  
}  

// 具体装饰器：糖  
public class SugarDecorator extends CoffeeDecorator {  
    public SugarDecorator(Coffee coffee) {  
        super(coffee);  
    }  

    @Override  
    public double getCost() {  
        return super.getCost() + 0.2; // 增加糖价格  
    }  

    @Override  
    public String getDescription() {  
        return super.getDescription() + ", with sugar";  
    }  
}  
</syntaxhighlight>  

=== 使用示例 ===  
<syntaxhighlight lang="java">  
public class Main {  
    public static void main(String[] args) {  
        Coffee coffee = new SimpleCoffee();  
        System.out.println("Cost: " + coffee.getCost() + "; Description: " + coffee.getDescription());  

        coffee = new MilkDecorator(coffee);  
        System.out.println("Cost: " + coffee.getCost() + "; Description: " + coffee.getDescription());  

        coffee = new SugarDecorator(coffee);  
        System.out.println("Cost: " + coffee.getCost() + "; Description: " + coffee.getDescription());  
    }  
}  
</syntaxhighlight>  

'''输出'''：  
<pre>  
Cost: 2.0; Description: Simple coffee  
Cost: 2.5; Description: Simple coffee, with milk  
Cost: 2.7; Description: Simple coffee, with milk, with sugar  
</pre>