Decorator Pattern

design-pattern/src/Decorator/Decorator

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+Decorator Pattern
+ - 동적으로 책임 추가
+
+
+예제 - 커피 제조 방법
+
+ - 에스프레소 : 커피의 기본
+ - 아메리카노 : 에스프레소 + 물
+ - 카페라떼 : 에스프레소 + 스팀밀크
+ - 헤이즐넛 : 아메리카노 + 헤이즐넛 시럽
+ - 카페모카 : 카페라떼 + 초콜릿
+ - 캬라멜 마끼아또 : 카페라떼 + 캬라멜 시럽
+
+

design-pattern/src/Decorator/Main.java

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+package Decorator;
+
+import Decorator.abst.IBeverage;
+import Decorator.concrete.Base;
+import Decorator.concrete.Espresso;
+import Decorator.concrete.Milk;
+
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        IBeverage beverage = new Base();
+        boolean done = false;
+        while (!done) {
+            System.out.println("음료 현재 가격 : " + beverage.getTotalPrice());
+            System.out.println("선택 : 1. 샷추가 / 2. 우유 추가");
+            switch (sc.nextInt()) {
+                case 0: done = true; break;
+                case 1: beverage = new Espresso(beverage); break;
+                case 2: beverage = new Milk(beverage); break;
+            }
+        }
+        System.out.println("음료 가격 : " + beverage.getTotalPrice());
+        sc.close();
+    }
+}

design-pattern/src/Decorator/abst/AbstAdding.java

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+package Decorator.abst;
+
+abstract public class AbstAdding implements IBeverage{
+
+    private IBeverage base;
+
+    public AbstAdding(IBeverage base) {
+        this.base = base;
+    }
+
+    @Override
+    public int getTotalPrice() {
+        return base.getTotalPrice();
+    }
+
+    protected IBeverage getBase() {
+        return base;
+    }
+}

design-pattern/src/Decorator/abst/IBeverage.java

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+package Decorator.abst;
+
+public interface IBeverage {
+
+    int getTotalPrice();
+}

design-pattern/src/Decorator/concrete/Base.java

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+package Decorator.concrete;
+
+import Decorator.abst.IBeverage;
+
+public class Base implements IBeverage {
+    @Override
+    public int getTotalPrice() {
+        return 0;
+    }
+}

design-pattern/src/Decorator/concrete/Espresso.java

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+package Decorator.concrete;
+
+import Decorator.abst.AbstAdding;
+import Decorator.abst.IBeverage;
+
+public class Espresso extends AbstAdding {
+
+    static protected int espressoCount = 0;
+
+    public Espresso(IBeverage base) {
+        super(base);
+    }
+
+    @Override
+    public int getTotalPrice() {
+        return super.getTotalPrice() + getAddPrice();
+    }
+
+    private static int getAddPrice() {
+        espressoCount += 1;
+        int addPrice = 100;
+        if (espressoCount > 1) {
+            addPrice = 70;
+        }
+        return addPrice;
+    }
+}

design-pattern/src/Decorator/concrete/Milk.java

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+package Decorator.concrete;
+
+import Decorator.abst.AbstAdding;
+import Decorator.abst.IBeverage;
+
+public class Milk extends AbstAdding {
+
+    public Milk(IBeverage base) {
+        super(base);
+    }
+
+    @Override
+    public int getTotalPrice() {
+        return super.getTotalPrice() + 50;
+    }
+}