rxjava countdown

CountDown.java

     Subscription subscription = Observable.interval(0, 1, TimeUnit.SECONDS)
                .take(seconds + 1)
                .map(new Func1<Long, Long>() {
                    @Override
                    public Long call(Long past) {
                        return seconds - past - 1;
                    }
                })
                .filter(new Func1<Long, Boolean>() {
                    @Override
                    public Boolean call(Long aLong) {
                        return aLong >= 0;
                    }
                })
                .subscribe(new RxAction<Long>() {
                    @Override
                    public void onNext(Long time) {
                        Log.e("xxxxxx", "onNext" + time);
                    }

                    @Override
                    public void onStart() {
                        Log.e("xxxxxx", "onStart");
                    }

                    @Override
                    public void onCompleted() {
                        Log.e("xxxxxx", "onCompleted");
                    }
                });

9.8.7.6.5.4.3.2.1.0.complete