Styjun

This question is often asked and resolved in many ways, but if I come back to the same question, it's because I'm a bit confused. This is my first time to deal with Realm ORM.

This repository class state for the implementation on db storage. Its take instance of Realm and ApiService

class LoginRepositoryImpl(var realm: Realm, var apiService: ApiService)
 override fun doLogin(email: String, password: String) 
 apiService.loginCheck(email, password)

 .flatMap t: EntityToken ->

 // check if user already exist and delete it
 val checkIfUserExist = getUserIfExist("email", email)

 if (checkIfUserExist != null) 
 realm.executeTransactionAsync 
 checkIfUserExist.deleteFromRealm()
 

 
 // insert user into DB
 realm.executeTransactionAsync bgRealm ->
 val user = bgRealm.createObject(UserModel::class.java, UserModel.cachedNextId)
 user.email = email
 user.logged = true
 
 // i want to make another request to server
 return@flatMap apiService.pingServer(t.refresh_token)
 
 .subscribeOn(Schedulers.io())
 .observeOn(AndroidSchedulers.mainThread())
 .subscribe( uR ->
 // make update of user table
 realm.executeTransactionAsync 
 getUserIfExist("email", email)?.fullname = uR.fullname
 
 
 

 //function to check if user instance already exist
 private fun getUserIfExist(field: String, email: String): UserModel? 
 return realm.where(UserModel::class.java)
 .equalTo(field, email)
 .findFirstAsync()

Ps.help me to resolve Realm access from incorrect thread

You can create wrapper over realm that will use Schedulers.single(). It will use the same thread everytime. But I think I had to get Realm instance from that thread too.
I did it the ugly way

public long count() throws RealmException 
 return Single.fromCallable(() -> realmService.getRealm().where(dataTypeClass).count())
 .subscribeOn(Schedulers.single())
 .blockingGet();

realmService.getRealm() returns Realm instance that is lazily loaded only once.

You can also just return Single and chain calls using RxJava.

I think i solve the problem by creating a new instance of Realm everytime i need to make a request.

I transformed my private function into this

 private fun getUserIfExist(db: Realm, email: String): UserModel? 
 return db.where(UserModel::class.java).equalTo("email", email).findFirst()

I created a new private function for the deleting

 private fun deleteInDb(db: Realm, email: String) 
 db.executeTransactionAsync 
 it.where(UserModel::class.java)
 .equalTo("email", email)
 .findFirst()
 

To write into the table i created a private function too

 private fun writeToDB(entityToken: EntityToken, email: String): String? 
 realm = Realm.getDefaultInstance()
 realm.executeTransactionAsync bgRealm ->
 var user = findInDb(bgRealm, email)
 if (user != null) 
 deleteInDb(bgRealm, email)
 
 user = bgRealm.createObject(UserModel::class.java, UserModel.cachedNextId)
 user!!.email = email
 user.token = entityToken.token
 user.refreshToken = entityToken.refresh_token
 user.logged = true
 
 realm.close()
 return entityToken.refresh_token

And finaly my doLogin function became

override fun doLogin(email: String, password: String) 
 apiService.loginCheck(email, password)
 .subscribeOn(Schedulers.newThread())
 .observeOn(Schedulers.computation())
 .map 
 // write to DB
 writeToDB(it, email, password)
 return@map it
 
 .flatMap ping ->
 //doPing to refresh token if not success
 if (!ping.success) 

 
 return@flatMap apiService.userInfoFromServer
 
 .observeOn(AndroidSchedulers.mainThread())
 .subscribe( uR ->
 updateUserInfo(uR, email)

 , error ->
 Log.e("tt", error.message)

 )
 
}

Its works but i got another problem. The fact that i am sending only Realm Object, so when i declared

realm = Realm.getDefaultInstance()

It changing my RealmConfiguration 'database name' by 'default name'

Every solution is welcome!