You should go with private constructor. If your class is abstract, it can be extended and objects can be created. As per my understanding from the question, what you want is non instantiable class. from Item 4 of Effective java : Attempting to enforce noninstantiability by making a class abstract does not work. The class … Read more
Using enum for something that’s not actually an enum is ugly and confusing. I’d say that’s enough reason not to do it. The “utility class” pattern is perfectly legitimate. If your tools don’t like it, that’s a problem with the tools.
Here’s the technique to have a private constructor and a public apply method. trait Meter { def m: Int } object Meter { def apply(m: Int): Meter = { MeterImpl(m) } private case class MeterImpl(m: Int) extends Meter { println(m) } } object Application extends App { val m1 = new Meter(10) // Forbidden val … Read more
You can use one of the overloads of Activator.CreateInstance to do this: Activator.CreateInstance(Type type, bool nonPublic) Use true for the nonPublic argument. Because true matches a public or non-public default constructor; and false matches only a public default constructor. For example: class Program { public static void Main(string[] args) { Type type=typeof(Foo); Foo f=(Foo)Activator.CreateInstance(type,true); } … Read more
Private constructor means a user cannot directly instantiate a class. Instead, you can create objects using something like the Named Constructor Idiom, where you have static class functions that can create and return instances of a class. The Named Constructor Idiom is for more intuitive usage of a class. The example provided at the C++ … Read more