Kotlin.kt

@Dao
interface NoteDao {
    @Insert(onConflict = OnConflictStrategy.ABORT)
    fun insert(note: Note): Long

    @Update(onConflict = OnConflictStrategy.ABORT)
    fun update(note: Note): Int

    @Query("SELECT * FROM notes")
    fun observeAllNotes(): Flowable<Note>

    @Query("SELECT * FROM notes WHERE id = :id")
    fun findById(id: Long): Note
}

class NoteDaoHelper internal constructor(private val noteDao: NoteDao) : NoteDao by noteDao {
    fun updateAndReturnNewValue(note: Note): Note {
        update(note)
        return findById(note.id)
    }

    override fun observeAllNotes(): Flowable<Note> {
        return noteDao.observeAllNotes().subscribeOn(Schedulers.io())
    }
}