【kotlin设计模式】Java的装饰器模式在kotlin的实现

装饰器模式

Java

/**
* 抽象组件
* /
public interface Animal{
	void eat();
}

/**
* 被装饰者
* /
public class Panda implements Animal{
	@Override
	public void eat(){
		System.out.println("什么都没有, 不知道吃什么")
	}
}

/**
* 装饰者组件
* /
public abstract class Food implements Animal{
	Animal animal;
	
	public Food(Animal animal){
		this.animal = animal;
	}
}

/**
* 具体装饰1
* /
public class BambooFood extends Food{
	public BambooFood(Animal animal){
		super(animal);
	}
	
	@Override
	public void eat(){
		super.eat();
		System.out.println("可以吃竹子");
	}
}

/**
* 具体装饰2
* /
public class CarrotFood extends Food {
	public CarrotFood(Animal animal){
		super(animal);
	}

	@Override
	public void eat(){
		super.eat();
		System.out.println("可以吃胡萝卜");
	}
}

public class Test{
	public static void main(String[] args){
		//创建被装饰者
		Panda panda = new Panda();
		//熊猫被装饰了竹子, 可以吃竹子
		BambooFood bambooFood = new BambooFood(panda);
		//可以吃竹子的熊猫, 被装饰了胡萝卜, 可以吃胡萝卜了
		CarrotFood carrotFood = new CarrotFood(bambooFood);
		carrotFood.eat();
	}
}

kotlin

fun Panda.bamboo(decorator: ()->Unit){
	eat()
	parintln("可以吃竹子")
	decorator()
}

fun Panda.carrot(decorator: ()->Unit){
	parintln("可以吃胡萝卜")
	decorator()
}

fun main(){
	Panda().run{
		bamboo{
			carrot{}
		}
	}
}