How about Realm?

I was just wondering to know your thoughts about the best way to implement [Realm](https://github.com/realm/realm-java) Entities.

Realm needs the Android Framework, so I cannot have Realm objects in the Domain Layer, so I'm thinking to create other Realm Entities in the Data Layer and then map Domain objects to Realm objects. Does it make sense?

Also, the Repository Interface must return Observables Realm Entities, because I could retrieve data from the Realm database if the cache is not expired. Can I move the Repository Interfaces to the Data Layer?

Thanks.