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

repeatWhen_zipWith_flatMap_example.java

private static final int COUNTER_START = 1;
private static final int ATTEMPTS = 5;
private static final int ORIGINAL_DELAY_IN_SECONDS = 10;

    // this is new methods chain in repeatWhen predicate call function
repeatWhen(new Func1<Observable<? extends Void>, Observable<?>>() {
    @Override
    public Observable<?> call (Observable < ?extends Void > observable){
        Log.v(TAG, "repeatWhen, call");

        return observable.zipWith(Observable.range(COUNTER_START, ATTEMPTS), new Func2<Void, Integer, Integer>() {
            @Override
            public Integer call(Void aVoid, Integer attempt) {
                Log.v(TAG, "zipWith, call, attempt " + attempt);
                return attempt;
            }
        }).flatMap(new Func1<Integer, Observable<?>>() {
            @Override
            public Observable<?> call(Integer repeatAttempt) {
                Log.v(TAG, "flatMap, call, repeatAttempt " + repeatAttempt);
                // increase the waiting time
                return Observable.timer(repeatAttempt * ORIGINAL_DELAY_IN_SECONDS, TimeUnit.SECONDS);
            }
        });
    }
})