RxJava Retry Web Service Connection incrementally if there is Network Kind of Error.

RetryWithDelay.java

public class RetryWithDelay implements Func1<Observable<? extends Throwable>, Observable<?>> {
    private int numberOfTry;
    private int delay;
    private int retryCount = 1;
    private final TimeUnit timeUnit;


    public RetryWithDelay(int numberOfTry, int delay, TimeUnit timeUnit) {
        this.numberOfTry = numberOfTry;
        this.delay = delay;
        this.timeUnit = timeUnit;
    }

    @Override
    public Observable<?> call(Observable<? extends Throwable> errors) {
        return errors
                .flatMap(error -> {
                    if(error instanceof IOException) {         // Network Error
                        int delayFinal = delay * retryCount;
                        retryCount++;
                        if (retryCount <= numberOfTry+1) {
                            // You might want to notify UI with EventBus etc... with Retry duration
                            Log.d("RetryWithDelay"+" call()", "retryCount " + delayFinal);
                            return Observable.timer((long) delayFinal, timeUnit);
                        } else {
                            return Observable.error(error); // Let them go to onError() after few retries
                        }
                    }else{  // Http Error or other Unexpected Error
                        return Observable.error(error); // Let them go to onError()
                    }

                });

    }
}

Screw this, use Coroutine and good-old while loop :D