// Telescoping constructor pattern - does not scale well! - Pages 11-12
/**
 * 营养成分表
 */
public class NutritionFacts {
    private final int servingSize;   // (mL)            required
    private final int servings;      // (per container) required
    private final int calories;      //                 optional
    private final int fat;           // (g)             optional
    private final int sodium;        // (mg)            optional
    private final int carbohydrate;  // (g)             optional
    /**
     * 重叠构造器模式：提供第一个只有必要参数的构造器
     */
    public NutritionFacts(int servingSize, int servings) {
        this(servingSize, servings, 0);
    }
    /**
     * 重叠构造器模式：第二个构造器有一个可选参数
     */
    public NutritionFacts(int servingSize, int servings, int calories) {
        this(servingSize, servings, calories, 0);
    }
    /**
     * 重叠构造器模式：第三个构造器在第二个构造器的基础上，加一个可选参数
     */
    public NutritionFacts(int servingSize, int servings, int calories, int fat) {
        this(servingSize, servings, calories, fat, 0);
    }
    /**
     * 重叠构造器模式：以此类推
     */
    public NutritionFacts(int servingSize, int servings, int calories, int fat, int sodium) {
        this(servingSize, servings, calories, fat, sodium, 0);
    }
    /**
     * 重叠构造器模式：以此类推
     */
    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(240, 8, 100, 0, 35, 27);
    }
}

// Builder Pattern - Pages 14-15
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;
    /**
     * 注意是static修饰, 作为NutritionFacts的静态成员类
     * 详细的讨论请参考：
     *     https://stackoverflow.com/questions/5007355/builder-pattern-in-effective-java
     */
    public static class Builder {
        // Required parameters
        private final int servingSize;
        private final int servings;
        // Optional parameters - initialized to default values
        private int calories      = 0;
        private int fat           = 0;
        private int carbohydrate  = 0;
        private int sodium        = 0;
        public Builder(int servingSize, int servings) {
            System.out.println("NutritionFacts.Builder init this[" + this + "]");
            this.servingSize = servingSize;
            this.servings    = servings;
        }
        // builder的setter()方法返回builder本身，以便可以把调用链接起来
        public Builder calories(int val) {
            calories = val;
            return this;
        }
        public Builder fat(int val) {
            fat = val;
            return this;
        }
        public Builder carbohydrate(int val) {
            carbohydrate = val;
            return this;
        }
        public Builder sodium(int val) {
            sodium = val;
            return this;
        }
        /**
         * build()方法可以检验这些约束条件
         * 如果违反了任何约束条件build方法就应该抛出IllegalSelectorException
         */
        public NutritionFacts build() {
            return new NutritionFacts(this);
        }
    }
    /**
     * 注意这是private修饰的
     */
    private NutritionFacts(Builder builder) {
        servingSize  = builder.servingSize;
        servings     = builder.servings;
        calories     = builder.calories;
        fat          = builder.fat;
        sodium       = builder.sodium;
        carbohydrate = builder.carbohydrate;
    }
    public static void main(String[] args) {
        // 不直接生成想要的对象，而是让客户端利用所有必要的参数调用NutritionFacts.Builder(int, int)创建一个builder对象
        // 然后客户端在builder对象调用类似于setter的方法,来设置每个相关的可选参数
        // 最后客户端调用无参的build()方法来生成不可变的对象NutritionFacts
        NutritionFacts cocaCola = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).build();
        NutritionFacts cocaCola2 = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).fat(7).build();
    }
}