Dynamically call Class with variable number of parameters in the constructor

Question

I know that it is possible to call a function with a variable number of parameters with call_user_func_array() found here -> http://php.net/manual/en/function.call-user-func

Answer 1

I've found here

Is there a call_user_func() equivalent to create a new class instance?

the example:

function createInstance($className, array $arguments = array())
{
    if(class_exists($className)) {
        return call_user_func_array(array(
            new ReflectionClass($className), 'newInstance'), 
            $arguments);
    }
    return false;
}

But can somebody tell me if there is an example for classes with protected constructors?