public class RpsChecker {

    private final int RATE_PER_SECOND = 1000; //Точность до миллисекунд.

    private long queryTimes[];
    private AtomicInteger lastIndex = new AtomicInteger(0);

    public RpsChecker(int rps) {
        this.queryTimes = new long[rps];
    }

    public boolean isRequestAllowed() {
        long currentTime = System.currentTimeMillis();
        int currentIndex = lastIndex.get();

        if (currentTime - queryTimes[currentIndex] > RATE_PER_SECOND) {
            int nextIndex = getNextIndex(currentIndex);
            while (!lastIndex.compareAndSet(currentIndex, nextIndex)) {
                currentIndex = lastIndex.get();
                if (currentTime - queryTimes[currentIndex] > RATE_PER_SECOND) {
                    nextIndex = getNextIndex(currentIndex);
                } else {
                    return false;
                }
            }
            queryTimes[currentIndex] = currentTime;
            return true;
        }
        return false;
    }

    private int getNextIndex(int currentIndex) {
        int nextIndex = currentIndex + 1;
        if (nextIndex >= queryTimes.length) {
            nextIndex = 0;
        }
        return nextIndex;
    }
}