HashMap<ProducerId, boolean[]> tracker = new HashMap<ProducerId, boolean[]>();
private synchronized void track(Message message) {
try {
MessageId id = new MessageId(message.getJMSMessageID());
ProducerId pid = id.getProducerId();
int seq = (int)id.getProducerSequenceId();
boolean[] ids = tracker.get(pid);
if (ids == null) {
ids = new boolean[TO_SEND + 1];
ids[seq] = true;