> For the complete documentation index, see [llms.txt](https://seungyeon-kang.gitbook.io/yeons-frame/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://seungyeon-kang.gitbook.io/yeons-frame/basic/java_advance/13.-decorator-pattern.md).

# Decorator Pattern

## Decorator Pattern

* 자바의 입출력 스트림은 decorator pattern 임
* 여러 decorator들을 활용하여 다양한 기능을 제공
* 상속 보다 유연한 구현 방식
* 데코레이터는 다른 데코레이터나 또는 컴포넌트를 포함해야 함
* 지속적인 기능의 추가와 제거가 용이함
* decorator와 component는 동일한 것이 아님 ( 기반 스트림 클래스가 직접 읽고 쓸수 있음, 보조 스트림은 추가적인 기능 제공)

![decorator](/files/i2TTT4zHjPDJcJQIbXGP)

## 커피를 만들어보아요\~

```
Decorator Pattern을 활용하여 커피를 만들어 봅시다.

아메리카노
카페 라떼 = 아메리카노 + 우유
모카 커피 = 아메리카노 + 우유 + 모카시럽
크림 올라간 모카커피 = 아메리카노 + 우유 + 모카시럽 + whipping cream

커피는 컴포넌트고, 우유, 모카시럽, whipping cream은 모두 데코레이터임
```

## 예제

```
public abstract class Coffee {
	
	public abstract void brewing();
}
```

```
public abstract class Decorator extends Coffee{

	Coffee coffee;
	public Decorator(Coffee coffee){
		this.coffee = coffee;
	}
	
	@Override
	public void brewing() {
		coffee.brewing();
	}

}
```

```
public class Latte extends Decorator{

	public Latte(Coffee coffee) {
		super(coffee);
	}

	
	public void brewing() {
		super.brewing();
		System.out.print("Adding Milk ");
	}
}
```

```
public class Mocha extends Decorator{

	public Mocha(Coffee coffee) {
		super(coffee);
		// TODO Auto-generated constructor stub
	}

	public void brewing() {
		super.brewing();
		System.out.print("Adding Mocha Syrup ");
	}
}
```

```
public class WhippedCream extends Decorator{

	public WhippedCream(Coffee coffee) {
		super(coffee);
	}

	public void brewing() {
		super.brewing();
		System.out.print("Adding WhippedCream ");
	}
}
```

```
public class KenyaAmericano extends Coffee{

	@Override
	public void brewing() {
		System.out.print("KenyaAmericano ");
	}

}
```

```
public class EtiopiaAmericano extends Coffee{

	@Override
	public void brewing() {
		System.out.print("EtiopiaAmericano ");
	}

}
```

```
public class CoffeeTest {

	public static void main(String[] args) {

		Coffee kenyaAmericano = new KenyaAmericano();
		kenyaAmericano.brewing();
		System.out.println();
		
		Coffee kenyaLatte = new Latte(kenyaAmericano);
		kenyaLatte.brewing();
		System.out.println();
		
		Mocha kenyaMocha = new Mocha(new Latte(new KenyaAmericano()));
		kenyaMocha.brewing();
		System.out.println();
		
		WhippedCream etiopiaWhippedMocha = 
				new WhippedCream(new Mocha(new Latte( new EtiopiaAmericano())));
		etiopiaWhippedMocha.brewing();
		System.out.println();
		
	}

}
```


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