class RxRetry<T>(val observableProvider:()->Observable<T>,val until: (T)->Boolean) {
  fun get():Observable<T>{
    return observableGetter().flatMap {
      if(until(it)) {
        Observable.just(it).concatWith(get())
      }else{
        Observable.just(it)
      }
    }
  }
}

//usage :
RxRetry({getDataFromServer()},{it.areMoreDataAvailable()}).get()