Server polling and retry operations when failed. With Retrofit and RxJava.

repeatWhen_flatMap.java

repeatWhen(new Func1<Observable<? extends Void>, Observable<?>>() {
    @Override
    public Observable<?> call(Observable<? extends Void> observable) {
        Log.v(TAG, "repeatWhen, call");

        return observable.flatMap(new Func1<Void, Observable<?>>() {
            @Override
            public Observable<?> call(Void aVoid) {
                if(mCounter > ATTEMPTS){
                    // terminate by ourselves
                    throw new RuntimeException();
                }
               return Observable.timer(mCounter++ * ORIGINAL_DELAY_IN_SECONDS, TimeUnit.SECONDS);
            }
        });
    }
})