DomainLayerExample.kt

// Domain Layer (Use Case)
class GetUserProfile(private val userRepository: UserRepository) {
    suspend operator fun invoke(userId: String): User {
        return userRepository.getUserById(userId)
    }
}

// Data Layer (Repository Implementation)
class UserRepositoryImpl(private val apiService: ApiService, private val userDao: UserDao) : UserRepository {
    override suspend fun getUserById(userId: String): User {
        // Decide whether to fetch data from network or local database
        return apiService.getUserById(userId)
    }
}