Kotlin Extension Functions + Entity Dao

DaoExtentions.kt

import com.example.db.ConversationDao.Properties.Mid
import com.example.db.UserDao.Properties.Username

fun UserDao.getByUsername(username: String): User =
        queryBuilder().where(Username.eq(username)).unique()

fun MessageDao.getMessage(mid: Long): Message =
        queryBuilder().where(Mid.eq(mid)).unique()

MainActivity.kt

import com.example.db.getByUsername
import com.example.db.getMessage

/**
 * Created by Davud.
 */
class MainActivity : Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        var user = DatabaseManager.userDao.getByUsername("David")
        var message = DatabaseManager.messageDao.getMessage(3)
    }
}

Using Kotlin Extension Functions with Entity Dao can provide readable code.