使用注释获取实体常量的选择列表

Question

Is it possible to use annotations to get a ChoiceList or array of specific type of class/entity constants?

I mean something like this:

class User{
    /**
     * @Item(Things,'Label 1')
     */
    const SOME_THING1=1;
    /**
     * @Item(Things,'Label 2')
     */
    const SOME_THING2=2;
    /**
     * @Item(Things,'Label 3')
     */
    const SOME_THING3=3;



    /**
     * @Item(OtherThings,'Label 1')
     */
    const SOME_OTHER_THING1=1;
    /**
     * @Item(OtherThings,'Label 2')
     */
    const SOME_OTHER_THING2=2;

    ...
}

and then:

$builder->add('thing', 'choice', array(
  'choice_list' => getChoiceListFromConsts('User','Things')
));

And I expect getChoiceListFromConsts('User','Things') to return something like:

array( 
     'Label 1' => 1,
     'Label 2' => 2,
     'Label 3' => 3
);

Is there a build-in feature for this in Symfony2 or is there any bundle that provide such a service?