The traditional builder pattern already handles this: simply take the mandatory parameters in the constructor. Of course, nothing prevents a caller from passing null, but neither does your method. The big problem I see with your method is that you either have a combinatorical explosion of classes with the number of mandatory parameters, or force … Read more
With design patterns, there usually is no “more advantageous” solution that works for all cases. It depends on what you need to implement. From Wikipedia: Builder focuses on constructing a complex object step by step. Abstract Factory emphasizes a family of product objects (either simple or complex). Builder returns the product as a final step, … Read more
Make the builder a static class. Then it will work. If it is non-static, it would require an instance of its owning class – and the point is not to have an instance of it, and even to forbid making instances without the builder. public class NutritionFacts { public static class Builder { } } … Read more