생성자 Builder pattern

Builder.java

package com.tistory.seungdols.effetive.ex_1;

/**
 * @PROJECT effectiveJava
 * @PACKAGE com.tistory.seungdols.effetive.ex_1
 * @WRITTER Administrator
 * @DATE 2015-09-21
 * @HISTORY
 * @DISCRIPT
 */
public class NutritionFactsBuild {
    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 class Builder{
        //primitive arg
        private final int servingSize;
        private final int servings;
        //optional arg
        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 carbohydrate(int val)
        {
            carbohydrate = val;
            return this;
        }
        public Builder sodium(int val)
        {
            sodium = val;
            return this;
        }
        public NutritionFactsBuild build()
        {
            return new NutritionFactsBuild(this);
        }
    }
    private NutritionFactsBuild(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) {
        NutritionFactsBuild coca = new NutritionFactsBuild.Builder(240,8).calories(500).fat(12).build();
    }
}