public StreamSummary(int capacity) {
        this.capacity = capacity;
        counterMap = new HashMap<T, ListNode2<Counter<T>>>();
        bucketList = new DoublyLinkedList<Bucket>();
    }
@Test
    public void testStreamSummary() {
        StreamSummary<String> vs = new StreamSummary<String>(3);
        String[] stream = {"X", "X", "Y", "Z", "A", "B", "C", "X", "X", "A", "A", "A"};
        for (String i : stream) {
            vs.offer(i);
            /*
        for(String s : vs.poll(3))
        System.out.print(s+" ");
             */
            System.out.println(vs);
        }
    }