The Builder pattern simulates named optional parameters(Java)

the Builder pattern is a good choice when designing classes whose constructors or static factories would have more than a handful of parameters.

/**
 * Created by xfyou 2017/5/27 14:41 14:42.
 * The Builder pattern simulates named optional parameters
 */
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 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) {
            this.servingSize = servingSize;
            this.servings = servings;
        }

        public Builder calories(int val) {
            this.calories = val;
            return this;
        }

        public Builder carbohydrate(int val) {
            this.carbohydrate = val;
            return this;
        }

        public Builder sodium(int val) {
            this.sodium = val;
            return this;
        }

        public NutritionFacts build() {
            return new NutritionFacts(this);
        }
    }

    public NutritionFacts(Builder builder) {
        this.calories = builder.calories;
        this.carbohydrate = builder.carbohydrate;
        this.fat = builder.fat;
        this.servings = builder.servings;
        this.servingSize = builder.servingSize;
        this.sodium = builder.sodium;
    }

    public int getServingSize() {
        return servingSize;
    }

    public int getServings() {
        return servings;
    }

    public int getCalories() {
        return calories;
    }

    public int getFat() {
        return fat;
    }

    public int getSodium() {
        return sodium;
    }

    public int getCarbohydrate() {
        return carbohydrate;
    }
}