private HashMap<String, DMaaPAlarmPolling> pollingTasks = new HashMap<>();
public synchronized void addSubscriber(Subscriber subscriber) {
String topic = subscriber.getTopic();
if (topic != null && !pollingTasks.containsKey(topic)) {
private HashMap<String, DMaaPAlarmPolling> pollingTasks = new HashMap<>();
public synchronized void addSubscriber(Subscriber subscriber) {
String topic = subscriber.getTopic();
if (topic != null && !pollingTasks.containsKey(topic)) {