private – Page 7 – Tarik Billa

Java: accessing private constructor with type parameters

January 23, 2023 by Tarik

Make sure you use getDeclaredConstructors when getting the constructor and set its accessibility to true since its private. Something like this should work. Constructor<Foo> constructor= (Constructor<Foo>) Foo.class.getDeclaredConstructors()[0]; constructor.setAccessible(true); Foo obj = constructor.newInstance(“foo”); System.out.println(obj); Update If you want to make use of getDeclaredConstructor, pass Object.class as an argument which translates to a generic T. Class fooClazz … Read more

Are private methods really safe?

January 20, 2023 by Tarik

It depends on what you mean by “safe”. If you’re running with a security manager that allows this sort of thing, then yes, you can do all kinds of nasty things with reflection. But then in that kind of environment the library can probably just be modified to make the method public anyway. Access control … Read more

Private Constructor in Python

January 8, 2023 by Tarik

The _ and __ prefixes don’t offer a solution to restricting instantiation of an object to a specific ‘factory’, however Python is a powerful toolbox and the desired behaviour can be achieved in more than one way (as @Jesse W at Z has demonstrated). Here is a possible solution that keeps the class publicly visible … Read more

Inheritance of private and protected methods in Python

January 6, 2023 by Tarik

Python has no privacy model, there are no access modifiers like in C++, C# or Java. There are no truly ‘protected’ or ‘private’ attributes. Names with a leading double underscore and no trailing double underscore are mangled to protect them from clashes when inherited. Subclasses can define their own __private() method and these will not … Read more

When to use @objc in Swift?

January 6, 2023 by Tarik

Another late answer, but none of the existing answers on this question really answer the OP’s question, which is: why the heck would you need to use @objc on a private class member, if @objc is there for interaction with Objective-C, and the member in question is private, meaning that even if you have Objective-C … Read more

Why are `private val` and `private final val` different?

January 5, 2023 by Tarik

So, this is just a guess, but it was a perennial annoyance in Java that final static variables with a literal on the right-hand side get inlined into bytecode as constants. That engenders a performance benefit sure, but it causes binary compatibility of the definition to break if the “constant” ever changed. When defining a … Read more

Why can I access private variables in the copy constructor?

January 4, 2023 by Tarik

The access modifiers work on class level, and not on object level. That is, two objects of the same class can access each others private data. Why: Primarily due to efficiency. It would be a non-negligible runtime overhead to check if this == other each time you access other.x which you would have to if … Read more

When should an attribute be private and made a read-only property? [closed]

December 19, 2022 by Tarik

Just my two cents, Silas Ray is on the right track, however I felt like adding an example. 😉 Python is a type-unsafe language and thus you’ll always have to trust the users of your code to use the code like a reasonable (sensible) person. Per PEP 8: Use one leading underscore only for non-public … Read more

Any reason to write the “private” keyword in C#?

December 19, 2022 by Tarik

AFAIK, private is the default everywhere in C# (meaning that if I don’t write public, protected, internal, etc. it will be private by default). (please correct me if wrong). This is not true. Types defined within a namespace (classes, structs, interfaces, etc) will be internal by default. Also, members within different types have different default … Read more

Is it possible to set private property via reflection?

November 29, 2022 by Tarik

Yes, it is: /// <summary> /// Returns a _private_ Property Value from a given Object. Uses Reflection. /// Throws a ArgumentOutOfRangeException if the Property is not found. /// </summary> /// <typeparam name=”T”>Type of the Property</typeparam> /// <param name=”obj”>Object from where the Property Value is returned</param> /// <param name=”propName”>Propertyname as string.</param> /// <returns>PropertyValue</returns> public static T … Read more