rx-java

问题 This is the case: I have the domain layer to provide data fetching interface for business logics, and I have 2 data sources: local database and remote network. It works like this: Request all users: DataRepository.getInstance().getUsers(); In DataRepository, there are 2 sources: LocalDataSource.getUsers() which fetches all users from local database, if there is no data then ignore this request. RemoteDataSource.getUsers() which requests latest user list from our server(Even if there is data

问题 I wonder whether I should use Schedulers.io() or Schedulers.newThread() when I access to database tables in parallel. For example, if I use Schedulers.io() to select the records from thousands of tables in parallel, a lot of threads newly created were in the thread pool after the task. Observabe.just("table1", "table2", "table3"...) .flatMap(t -> { // creating the observable that emits the record return Observable create(s -> { Record rec = selectFrom(t); s.onNext(rec); s.onCompleted(); })

问题 I wonder whether I should use Schedulers.io() or Schedulers.newThread() when I access to database tables in parallel. For example, if I use Schedulers.io() to select the records from thousands of tables in parallel, a lot of threads newly created were in the thread pool after the task. Observabe.just("table1", "table2", "table3"...) .flatMap(t -> { // creating the observable that emits the record return Observable create(s -> { Record rec = selectFrom(t); s.onNext(rec); s.onCompleted(); })

问题 How do i update a source observable on retry? List<String> ids = new ArrayList<>(); // A,B,C Observable.from(ids) .retryWhen(errors -> { return errors .zipWith(Observable.range(0, 1), (n, i) -> i) .flatMap(retryCount -> Observable.timer((long) Math.pow(2, retryCount), TimeUnit.MINUTES)); }) .subscribe(....); now rather than passing //A,B,C as ids if i want to pass some other values. How do i do it? or is this even the right approach? 回答1: Use defer . This would allow ids to be re-computed:

问题 How do i update a source observable on retry? List<String> ids = new ArrayList<>(); // A,B,C Observable.from(ids) .retryWhen(errors -> { return errors .zipWith(Observable.range(0, 1), (n, i) -> i) .flatMap(retryCount -> Observable.timer((long) Math.pow(2, retryCount), TimeUnit.MINUTES)); }) .subscribe(....); now rather than passing //A,B,C as ids if i want to pass some other values. How do i do it? or is this even the right approach? 回答1: Use defer . This would allow ids to be re-computed:

问题 I imagine that this is a common problem, but after some searching I wasn't able to find anything relevant. The problem I'm having is that I'm getting a No Hibernate Session bound to thread exception when annotating my resource method with @UnitOfWork and inside my resource method, making an asynchronous DAO call. The idea behind this design is to make the database call on a separate I/O thread so that it frees up the Jersey resource thread. Unfortunately, as the exception says, this

问题 I imagine that this is a common problem, but after some searching I wasn't able to find anything relevant. The problem I'm having is that I'm getting a No Hibernate Session bound to thread exception when annotating my resource method with @UnitOfWork and inside my resource method, making an asynchronous DAO call. The idea behind this design is to make the database call on a separate I/O thread so that it frees up the Jersey resource thread. Unfortunately, as the exception says, this

问题 I imagine that this is a common problem, but after some searching I wasn't able to find anything relevant. The problem I'm having is that I'm getting a No Hibernate Session bound to thread exception when annotating my resource method with @UnitOfWork and inside my resource method, making an asynchronous DAO call. The idea behind this design is to make the database call on a separate I/O thread so that it frees up the Jersey resource thread. Unfortunately, as the exception says, this

问题 I have a class called Student and it has two fields grade and school . Both of two fields need to be fetched from remote server. When two result returned, I new a Student object. With help of RxJava , I have done it in two ways, one in flatMap and another in zip operator. Observable<String> gradeObservable = Observable.create((ObservableOnSubscribe<String>) emitter -> { Thread.sleep(1000); emitter.onNext("senior"); }).subscribeOn(Schedulers.io()); Observable<String> schoolObservable =

问题 I have a class called Student and it has two fields grade and school . Both of two fields need to be fetched from remote server. When two result returned, I new a Student object. With help of RxJava , I have done it in two ways, one in flatMap and another in zip operator. Observable<String> gradeObservable = Observable.create((ObservableOnSubscribe<String>) emitter -> { Thread.sleep(1000); emitter.onNext("senior"); }).subscribeOn(Schedulers.io()); Observable<String> schoolObservable =