Question

I’m wondering if there is a “better” way to do this:

class Foo {
    final public function bar() {
        if (is_subclass_of(get_called_class(), __CLASS__)) {
            throw new Exception();
        }
    }
}

class Bar extends Foo {
    public function baz() {
        parent::bar(); // shouldn't be allowed
    }
}

Essentially, I want certain methods in my parent class to prohibit child classes from calling them. This needs to be bullet-proof, which I doubt this is, so if you know how this could be circumvented, that’s what I’m interested in knowing (along with how to prevent it, if possible).

Edit: For everyone suggesting private methods, this is not an option, as I need the interface to remain public to be externally accessible. Sorry, I guess I assumed that would be obvious.

Answer 1

class Foo {
    final public function bar() {
        if (is_subclass_of(get_called_class(), __CLASS__)) {
            throw new Exception('No cookies for you!');
        }
        echo 'Failure!';
    }
}

class Bar extends Foo {
    public function baz() {
        try{
                Foo::bar(); // shouldn't be allowed
        } catch (Exception $e){
                echo $e->getMessage();
        }
        try{
                $func = function() {Foo::bar();}; // is allowed, nags somewhat about it should't be called statically..
                $func();
        } catch (Exception $e){
                echo $e->getMessage();
        }
    }
}
$b = new Bar();
$b->baz();