This file is responsible for organizing communication between local and remote data sources (storages) and passing result with RxJava Observables

Repository.kt

open class Repository private constructor(
        remoteDataSource: DataSource,
        localDataSource: DataSource)
    : DataSource {

    private val mRemoteDataSource = remoteDataSource
    private val mLocalDataSource = localDataSource

    companion object {
        private var INSTANCE: Repository? = null


        fun getInstance(remoteDataSource: DataSource, localDataSource: DataSource): Repository {
            if (INSTANCE == null) {
                INSTANCE = Repository(remoteDataSource, localDataSource)
            }
            return INSTANCE!!

        }

        /**
         * Used to force {@link #getInstance(TasksDataSource, TasksDataSource)} to create a new instance
         * next time it's called. IMPORTANT FOR TESTS
         */
        @VisibleForTesting
        fun destroyInstance() {
            INSTANCE = null
        }

    }
    
    //... some other methods
    
    override fun getToken(): Flowable<Optional<String>> {
        return mLocalDataSource.getToken()
    }

    override fun authorize(credentials: Credentials): Flowable<String> {
        return mRemoteDataSource.authorize(credentials)
                .doOnNext { token ->
                    saveToken(token).subscribe()
                }
    }


    override fun getConversationId(): Flowable<Optional<String>> {
        //TODO rewrite to pass exception, @see getCreditCards()
        val localConversationId = mLocalDataSource.getConversationId()
        val remoteConversationId = mRemoteDataSource.getConversationId()
                .doOnNext { conversationId ->
                    mLocalDataSource.saveConversationId(conversationId.toNullable()!!).subscribe()
                }.onErrorReturn { null.toOptional() }
        return Flowable.zip(localConversationId, remoteConversationId,
                BiFunction<Optional<String>, Optional<String>, Optional<String>> { local, remote ->
                    remote.toNullable()?.let { remote } ?: local
                })
    }


    override fun getLayerIdentityToken(identityTokenBody: DevGetVoilaService.IdentityTokenBody): Flowable<String> {
        return mRemoteDataSource.getLayerIdentityToken(identityTokenBody)
    }

    override fun saveToken(token: String): Single<Boolean> {
        return mLocalDataSource.saveToken(token)
    }

    override fun removeToken(): Single<Boolean> {
        return mLocalDataSource.removeToken()
    }

    override fun selectWidget(model: Model, id: Int): Completable {
        return mRemoteDataSource.selectWidget(model, id)
    }

    override fun selectWidgetWithCF(model: Model, optionId: Int, taskId: Int, state: String): Completable {
        return mRemoteDataSource.selectWidgetWithCF(model, optionId, taskId, state)
    }

    override fun removeAll(): Single<Boolean> {
        return mLocalDataSource.removeAll()
    }

    override fun removeConversationId(): Single<Boolean> {
        return mLocalDataSource.removeConversationId()
    }

    override fun saveConversationId(conversationId: String): Single<Boolean> {
        return mLocalDataSource.saveConversationId(conversationId)
    }

    override fun resetPassword(email: String): Completable {
        return mRemoteDataSource.resetPassword(email)
    }

    override fun saveProfile(profile: Profile): Completable {
        return mRemoteDataSource.saveProfile(profile)
                .andThen(mLocalDataSource.saveProfile(profile))
    }

    override fun getProfile(): Single<Profile> {
        return getSettings().map { ObjectMapper.mapToProfile(it.toNullable()) }
    }

    override fun saveSettings(settings: UserSettings): Completable {
        return mLocalDataSource.saveSettings(settings)
    }

    override fun saveAccount(account: UserAccount): Completable {
        return mRemoteDataSource.saveAccount(account)
                .andThen(mLocalDataSource.saveAccount(account))
    }
    
    //... some other methods
    
}