Re: Class Access Modifiers

Hello, On Wed, Mar 9, 2011 at 10:02 AM, Jarrod Nettles <JNettles@inccrra.org> wrote: > Interesting question. My gut tells me not (as does three years of C# experience). I’m sure > that everyone will have a different opinion on this but to me it seems taboo that a child class > override the visibility of the parent class. For example, PHP currently does not allow you to > override a method with a lower or higher visibility than the parent – I can’t go from protected > to public or vice versa. Visibility must be maintained throughout the class hierarchy. > Actually, class properties and methods can have a higher visibility than their parents, just not a lower one. E.g.: <?php error_reporting(E_ALL | E_STRICT); class foo { protected function bar() { } } class baz extends foo { public function bar() { } } class foobar extends baz { protected function bar () { } } ?> You get the following error: Fatal error: Access level to foobar::bar() must be public (as in class baz) in ... ------- That said, I wouldn't think that visibility modifiers on classes need to follow the same pattern. In the case of properties and methods, I think the rationale is that child classes should be compatible from an interface standpoint with their parents. That same logic may not transfer to class visibility modifiers. I am certainly no expert, but I'm curious what the use case is for class visibility modifiers? On Wed, Mar 9, 2011 at 7:11 AM, Hannes Landeholm <landeholm@gmail.com> wrote: > Currently I'm forced to use huge internal classes for my framework because dividing them into smaller classes would expose internal behavior to the "outside"... the application layer. > This doesn't necessarily make sense to me. Isn't it the end-developer's problem if they start instantiating classes in weird ways? It doesn't seem the same as having a private method, since in that case the end-developer presumably already has an object instance, and you want to guide them to the correct interface for interacting with it, whereas in an application, one would think that the end-developer wouldn't simply be instantiating classes by themselves all over the place. Chad