There is no other way to reference parent's method implementation on PHP. There is nothing wrong with your code, PHPMD is drunk. The only problem you'd have with static access is because PHP allows you to call an instance method as a static method if it does not reference $this
variable, but there is no point on doing so. You can ignore this kind of warning.
Edit:
If you have something like this:
class Foo {
public function bar() {
echo 'bar';
}
}
PHP will allow you to do:
Foo::bar(); // works
But if you have this:
class Foo {
private $bar = 'bar';
public function bar() {
echo $this->bar;
}
}
Foo::bar(); // fatal error