code: public BuildableType.Builder builderFactory(BuilderFactory builderFactory) {
      this.builderFactory = Objects.requireNonNull(builderFactory);
      _unsetProperties.remove(Property.BUILDER_FACTORY);
      return (BuildableType.Builder) this;
    }
docs: Sets the value to be returned by {@link BuildableType#builderFactory()}.
  
  @return this {@code Builder} object
  @throws NullPointerException if {@code builderFactory} is null