public FIXOutgoingMessageHandler() 
{
        countersMap = new HashMap< String, Integer >();
        messagesMap = new HashMap< String, Map< Integer,Object[] > >();
}

 public  void cleanUpMessages(String session) 
{
        if (countersMap.containsKey(session)) {
            int expectedValue = countersMap.get(session);
            Map< Integer,  Object[] > messages = messagesMap.get(session);
            while (!messages.isEmpty()) {
                Object[] obj = messages.get(expectedValue);
                if (obj != null) {
                    Message message = (Message) obj[0];
                    SessionID sessionID = (SessionID) obj[1];
                    try {
                        Session.sendToTarget(message, sessionID);
                    } catch (SessionNotFound ignore) { }
                    messages.remove(expectedValue);
                }
                expectedValue++;
            }
            messagesMap.remove(session);
            countersMap.remove(session);
        }
}

 public synchronized  void sendMessage(Message message,
    SessionID targetSession,
    String sourceSession,
    int counter,
    MessageContext msgCtx,
    String targetEPR) throws SessionNotFound 
{
        if (sourceSession != null && counter != -1) {
            int expectedValue;
            if (countersMap.containsKey(sourceSession)) {
                expectedValue = countersMap.get(sourceSession);
            }
            else {
                //create new entries in the respective Maps
                //counter starts at 1
                countersMap.put(sourceSession, 1);
                messagesMap.put(sourceSession, new HashMap< Integer,Object[] >());
                expectedValue = 1;
            }
            if (expectedValue == counter) {
                sendToTarget(msgCtx, targetEPR, message, targetSession);
                countersMap.put(sourceSession, expectedValue++);
                sendQueuedMessages(expectedValue, sourceSession);
            }
            else {
                //save the message to be sent later...
                Map< Integer,Object[] > messages = messagesMap.get(sourceSession);
                Object[] obj = new Object[4];
                obj[0] = message;
                obj[1] = targetSession;
                obj[2] = msgCtx;
                obj[3] = targetEPR;
                messages.put(counter, obj);
                messagesMap.put(sourceSession, messages);
            }
        }
        else {
            //insufficient information to send the messages in order...
            // send it right away...
            sendToTarget(msgCtx, targetEPR, message, targetSession);
        }
}

Performs the actual send operation on the message. Tries to send the messages in the order they arrived over the FIX transport

 public  void setSessionFactory(FIXSessionFactory sessionFactory) 
{
        this.sessionFactory = sessionFactory;
}