#10 effective java: item 2

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/builder/BuilderTest.java

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+package com.example.effectivejava.chapter01.item02.builder;
+
+public class BuilderTest {
+
+    public static void main(String[] args) {
+        new NutritionFacts.Builder(10, 10)
+                .calories(10)
+                .build();
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/builder/NutritionFacts.java

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+package com.example.effectivejava.chapter01.item02.builder;
+
+// 코드 2-3 빌더 패턴 - 점층적 생성자 패턴과 자바빈즈 패턴의 장점만 취했다. (17~18쪽)
+public class NutritionFacts {
+    private final int servingSize;
+    private final int servings;
+    private final int calories;
+    private final int fat;
+    private final int sodium;
+    private final int carbohydrate;
+
+    public static void main(String[] args) {
+        NutritionFacts cocaCola = new Builder(240, 8)
+                .calories(100)
+                .sodium(35)
+                .carbohydrate(27).build();
+    }
+
+    public static class Builder {
+        // 필수 매개변수
+        private final int servingSize;
+        private final int servings;
+
+        // 선택 매개변수 - 기본값으로 초기화한다.
+        private int calories      = 0;
+        private int fat           = 0;
+        private int sodium        = 0;
+        private int carbohydrate  = 0;
+
+        public Builder(int servingSize, int servings) {
+            this.servingSize = servingSize;
+            this.servings    = servings;
+        }
+
+        public Builder calories(int val) {
+            calories = val;
+            return this;
+        }
+        public Builder fat(int val) {
+            fat = val;
+            return this;
+        }
+        public Builder sodium(int val) {
+            sodium = val;
+            return this;
+        }
+        public Builder carbohydrate(int val) {
+            carbohydrate = val;
+            return this;
+        }
+
+        public NutritionFacts build() {
+            return new NutritionFacts(this);
+        }
+    }
+
+    private NutritionFacts(Builder builder) {
+        servingSize  = builder.servingSize;
+        servings     = builder.servings;
+        calories     = builder.calories;
+        fat          = builder.fat;
+        sodium       = builder.sodium;
+        carbohydrate = builder.carbohydrate;
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/hierarchicalbuilder/Calzone.java

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+package com.example.effectivejava.chapter01.item02.hierarchicalbuilder;
+
+// 코드 2-6 칼초네 피자 - 계층적 빌더를 활용한 하위 클래스 (20~21쪽)
+public class Calzone extends Pizza {
+    private final boolean sauceInside;
+
+    public static class Builder extends Pizza.Builder<Builder> {
+        private boolean sauceInside = false; // 기본값
+
+        public Builder sauceInside() {
+            sauceInside = true;
+            return this;
+        }
+
+        @Override public Calzone build() {
+            return new Calzone(this);
+        }
+
+        @Override protected Builder self() { return this; }
+    }
+
+    private Calzone(Builder builder) {
+        super(builder);
+        sauceInside = builder.sauceInside;
+    }
+
+    @Override public String toString() {
+        return String.format("%s로 토핑한 칼초네 피자 (소스는 %s에)",
+                toppings, sauceInside ? "안" : "바깥");
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/hierarchicalbuilder/NyPizza.java

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+package com.example.effectivejava.chapter01.item02.hierarchicalbuilder;
+
+// 코드 2-5 뉴욕 피자 - 계층적 빌더를 활용한 하위 클래스 (20쪽)
+public class NyPizza extends Pizza {
+    public enum Size { SMALL, MEDIUM, LARGE }
+    private final Size size;
+
+    public static class Builder extends Pizza.Builder<NyPizza.Builder> {
+        private final Size size;
+
+        public Builder(Size size) {
+            this.size = Objects.requireNonNull(size);
+        }
+
+        @Override public NyPizza build() {
+            return new NyPizza(this);
+        }
+
+        @Override protected Builder self() { return this; }
+    }
+
+    private NyPizza(Builder builder) {
+        super(builder);
+        size = builder.size;
+    }
+
+    @Override public String toString() {
+        return toppings + "로 토핑한 뉴욕 피자";
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/hierarchicalbuilder/Pizza.java

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+package com.example.effectivejava.chapter01.item02.hierarchicalbuilder;// 코드 2-4 계층적으로 설계된 클래스와 잘 어울리는 빌더 패턴 (19쪽)
+
+// 참고: 여기서 사용한 '시뮬레이트한 셀프 타입(simulated self-type)' 관용구는
+// 빌더뿐 아니라 임의의 유동적인 계층구조를 허용한다.
+
+import java.util.EnumSet;
+import java.util.Objects;
+import java.util.Set;
+
+public abstract class Pizza {
+    public enum Topping { HAM, MUSHROOM, ONION, PEPPER, SAUSAGE }
+    final Set<Topping> toppings;
+
+    abstract static class Builder<T extends Builder<T>> {
+        EnumSet<Topping> toppings = EnumSet.noneOf(Topping.class);
+        public T addTopping(Topping topping) {
+            toppings.add(Objects.requireNonNull(topping));
+            return self();
+        }
+
+        abstract Pizza build();
+
+        // 하위 클래스는 이 메서드를 재정의(overriding)하여
+        // "this"를 반환하도록 해야 한다.
+        protected abstract T self();
+    }
+    
+    Pizza(Builder<?> builder) {
+        toppings = builder.toppings.clone(); // 아이템 50 참조
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/hierarchicalbuilder/PizzaTest.java

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+package com.example.effectivejava.chapter01.item02.hierarchicalbuilder;
+
+import static com.example.effectivejava.chapter01.item02.hierarchicalbuilder.NyPizza.Size.SMALL;
+import static com.example.effectivejava.chapter01.item02.hierarchicalbuilder.Pizza.Topping.*;
+
+// 계층적 빌더 사용 (21쪽)
+public class PizzaTest {
+    public static void main(String[] args) {
+        NyPizza pizza = new NyPizza.Builder(SMALL)
+                .addTopping(SAUSAGE)
+                .addTopping(ONION).build();
+
+        Calzone calzone = new Calzone.Builder()
+                .addTopping(HAM).sauceInside().build();
+        
+        System.out.println(pizza);
+        System.out.println(calzone);
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/javabeans/NutritionFacts.java

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+package com.example.effectivejava.chapter01.item02.javabeans;
+
+// 코드 2-2 자바빈즈 패턴 - 일관성이 깨지고, 불변으로 만들 수 없다. (16쪽)
+public class NutritionFacts {
+    // 필드 (기본값이 있다면) 기본값으로 초기화된다.
+    private int servingSize  = -1; // 필수; 기본값 없음
+    private int servings     = -1; // 필수; 기본값 없음
+    private int calories     = 0;
+    private int fat          = 0;
+    private int sodium       = 0;
+    private int carbohydrate = 0;
+    private boolean healthy;
+
+    public NutritionFacts() { }
+
+    public void setServingSize(int servingSize) {
+        this.servingSize = servingSize;
+    }
+
+    public void setServings(int servings) {
+        this.servings = servings;
+    }
+
+    public void setCalories(int calories) {
+        this.calories = calories;
+    }
+
+    public void setFat(int fat) {
+        this.fat = fat;
+    }
+
+    public void setSodium(int sodium) {
+        this.sodium = sodium;
+    }
+
+    public void setCarbohydrate(int carbohydrate) {
+        this.carbohydrate = carbohydrate;
+    }
+
+    public void setHealthy(boolean healthy) {
+        this.healthy = healthy;
+    }
+
+    public static void main(String[] args) {
+        NutritionFacts cocaCola = new NutritionFacts();
+        cocaCola.setServingSize(240);
+        cocaCola.setServings(8);
+
+        cocaCola.setCalories(100);
+        cocaCola.setSodium(35);
+        cocaCola.setCarbohydrate(27);
+    }
+}

effective-java/src/main/java/com/example/effectivejava/chapter01/item02/telescopingconstructor/NutritionFacts.java

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+package com.example.effectivejava.chapter01.item02.telescopingconstructor;
+
+// 코드 2-1 점층적 생성자 패턴 - 확장하기 어렵다! (14~15쪽)
+public class NutritionFacts {
+    private final int servingSize;  // (mL, 1회 제공량)     필수
+    private final int servings;     // (회, 총 n회 제공량)  필수
+    private final int calories;     // (1회 제공량당)       선택
+    private final int fat;          // (g/1회 제공량)       선택
+    private final int sodium;       // (mg/1회 제공량)      선택
+    private final int carbohydrate; // (g/1회 제공량)       선택
+
+    public NutritionFacts(int servingSize, int servings) {
+        this(servingSize, servings, 0);
+    }
+
+    public NutritionFacts(int servingSize, int servings,
+                          int calories) {
+        this(servingSize, servings, calories, 0);
+    }
+
+    public NutritionFacts(int servingSize, int servings,
+                          int calories, int fat) {
+        this(servingSize, servings, calories, fat, 0);
+    }
+
+    public NutritionFacts(int servingSize, int servings,
+                          int calories, int fat, int sodium) {
+        this(servingSize, servings, calories, fat, sodium, 0);
+    }
+
+    public NutritionFacts(int servingSize, int servings,
+                          int calories, int fat, int sodium, int carbohydrate) {
+        this.servingSize  = servingSize;
+        this.servings     = servings;
+        this.calories     = calories;
+        this.fat          = fat;
+        this.sodium       = sodium;
+        this.carbohydrate = carbohydrate;
+    }
+
+    public static void main(String[] args) {
+        NutritionFacts cocaCola =
+                new NutritionFacts(10, 10);
+    }
+    
+}