inver

    public static synchronized AircraftDb get(final Context context) {
        if (instance == null) {
            instance = Room.databaseBuilder(context.getApplicationContext(), AircraftDb.class, DATABASE_NAME)
                    .fallbackToDestructiveMigrationFrom(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
                    .addCallback(new Callback() {
                        @Override
                        public void onCreate(@NonNull SupportSQLiteDatabase db) {
                            final StopWatch sw = new StopWatch();
                            sw.start();

inver

    public LiveData<AircraftDto> getAircraftLiveData() {
        MediatorLiveData<AircraftDto> res = new MediatorLiveData<>();

        LiveData<AircraftDto> aircraftDtoLiveData = dao.getById(aircraftId);
        LiveData<List<CountryDto>> countriesLiveData = dao.getCountriesByAircraftId(aircraftId);

        MergerObserver merger = new MergerObserver(res, aircraftDtoLiveData, countriesLiveData);
        res.addSource(aircraftDtoLiveData, merger);
        res.addSource(countriesLiveData, merger);

inver

    @RequiredArgsConstructor
    private static class MergerObserver implements Observer {
        private AtomicInteger count = new AtomicInteger(2);

        private final MediatorLiveData<AircraftDto> mediatorLiveData;
        private final LiveData<AircraftDto> aircraftLiveData;
        private final LiveData<List<CountryDto>> countriesLiveData;

        @Override
        public synchronized void onChanged(@Nullable Object object) {

inver

@NoArgsConstructor
@EqualsAndHashCode
public class AircraftEntity {
    @PrimaryKey
    public int id;
    @NonNull
    public String name;
}

@NoArgsConstructor

inver

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.commons.io.IOUtils;
import ru.histone.Histone;
import ru.histone.HistoneBuilder;
import ru.histone.HistoneException;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;