Hi,

I'm implementing some functionality around filters which will ideally work for both ORM and ODM. The API for managing filters is different on `Doctrine\ORM\EntityManager` and `Doctrine\ODM\MongoDB\DocumentManager`, while the CouchDB implementation of ODM has no filter concept.

For example, ORM EntityManager has getFilters(), hasFilters(), while ODM MongoDB DocumentManager has getFilterCollection().

I was wondering what your thoughts were on defining the filter API in an interface, to improve consistency when implementing cross-library functionality?

Thanks,
Craig