# FIXOutgoingMessageHandler.java

    /*
     *  Licensed to the Apache Software Foundation (ASF) under one
     *  or more contributor license agreements.  See the NOTICE file
     *  distributed with this work for additional information
     *  regarding copyright ownership.  The ASF licenses this file
     *  to you under the Apache License, Version 2.0 (the
     *  "License"); you may not use this file except in compliance
     *  with the License.  You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     *  Unless required by applicable law or agreed to in writing,
     *  software distributed under the License is distributed on an
     *   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     *  KIND, either express or implied.  See the License for the
     *  specific language governing permissions and limitations
     *  under the License.
     */

    package org.apache.synapse.transport.fix;

    import org.apache.axis2.context.MessageContext;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import quickfix.Message;
    import quickfix.Session;
    import quickfix.SessionID;
    import quickfix.SessionNotFound;

    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;

    /**
     * FIXOutgoingMessageHandler makes sure that messages are delivered in the order they were received by
     * a FIX acceptor. In case the message arrived over a different transport still this class will try to
     * put the messages in correct order based on the counter value of the message.
     */
    public class FIXOutgoingMessageHandler {

        private static final Log log = LogFactory.getLog(FIXOutgoingMessageHandler.class);

        private Map<String, Integer> countersMap;
        private Map<String, Map<Integer,Object[]>> messagesMap;
        private FIXSessionFactory sessionFactory;

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

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

        /**
         * Performs the actual send operation on the message. Tries to send the messages in the order they
         * arrived over the FIX transport
         *
         * @param message the FIX message to be sent
         * @param targetSession ID of the target FIXSession
         * @param sourceSession String that uniquely identifies the incoming session
         * @param counter application level sequence number of the message
         * @param msgCtx Axis2 MessageContext for the outgoing message
         * @param targetEPR the target EPR to forward the message
         *
         * @throws SessionNotFound on error
         */
        public synchronized void sendMessage(Message message, SessionID targetSession, String sourceSession,
                                int counter, MessageContext msgCtx, String targetEPR) throws SessionNotFound {

            boolean ignoreOrder = "true".equals(msgCtx.getProperty(FIXConstants.FIX_IGNORE_ORDER));
            if (sourceSession != null && counter != -1 && !ignoreOrder) {

                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 ConcurrentHashMap<Integer,Object[]>());
                    expectedValue = 1;
                }

                if (expectedValue == counter) {
                    sendToTarget(msgCtx, targetEPR, message, targetSession);
                    if (FIXConstants.DEFAULT_COUNTER_UPPER_LIMIT == expectedValue) {
                        if (log.isDebugEnabled()) {
                            log.debug("Outgoing request counter rolled over for the session: " +
                                    sourceSession + " (from " + expectedValue + ")");
                        }
                        expectedValue = 1;
                    }
                    countersMap.put(sourceSession, ++expectedValue);
                    sendQueuedMessages(expectedValue, sourceSession);
                }
                else {
                    if (log.isDebugEnabled()) {
                        log.debug("Source session: " + sourceSession + " - Expected sequence number (" +
                                expectedValue + ") does not match with the actual sequence number (" +
                                counter + "). Holding the message back for later delivery.");
                    }

                    //save the message to be sent later...
                    Map<Integer,Object[]> messages = messagesMap.get(sourceSession);
                    Object[] obj = new Object[] { message, targetSession, msgCtx, targetEPR } ;
                    messages.put(counter, obj);
                }
            }
            else {
                //insufficient information to send the messages in order...
                // send it right away...
                sendToTarget(msgCtx, targetEPR, message, targetSession);
            }
        }

        /**
         * Sends the FIX message to the given target session. If MessageContext and the target EPR
         * are not null then save the outgoing MessageContext in the FIX application to handle the
         * response.
         *
         * @param msgCtx the Axis2 MessageContext of the outgoing message
         * @param targetEPR the target EPR to send the message
         * @param message the FIX message
         * @param sessionID the ID of the target FIX session
         *
         * @throws SessionNotFound on error
         */
        private void sendToTarget(MessageContext msgCtx, String targetEPR, Message message,
                                  SessionID sessionID) throws SessionNotFound {
            if (msgCtx != null && targetEPR != null) {
                FIXIncomingMessageHandler messageHandler = (FIXIncomingMessageHandler) sessionFactory.
                        getApplication(targetEPR);
                if (messageHandler != null) {
                    messageHandler.setOutgoingMessageContext(msgCtx);
                }
            }
            Session.sendToTarget(message, sessionID);
        }

        /**
         * Sends any messages in the queues. Maintains the order of the messages.
         *
         * @param expectedValue expected counter value
         * @param session source FIX session
         *
         * @throws SessionNotFound on error
         */
        private void sendQueuedMessages(int expectedValue, String session) throws SessionNotFound {
            Map<Integer, Object[]> messages = messagesMap.get(session);
            Object[] obj = messages.get(expectedValue);
            while (obj != null) {
                Message message = (Message) obj[0];
                SessionID sessionID = (SessionID) obj[1];
                MessageContext msgCtx = null;
                String targetEPR = null;
                if (obj[2] != null) {
                    msgCtx = (MessageContext) obj[2];
                    targetEPR = (String) obj[3];
                }

                if (log.isDebugEnabled()) {
                    log.debug("Source session: " + session + " - Sending the previously queued message " +
                            "with the sequence number: " + expectedValue);
                }
                sendToTarget(msgCtx, targetEPR, message, sessionID);
                messages.remove(expectedValue);
                if (FIXConstants.DEFAULT_COUNTER_UPPER_LIMIT == expectedValue) {
                    if (log.isDebugEnabled()) {
                        log.debug("Outgoing request counter rolled over for the session: " + session +
                            " (from " + expectedValue + ")");
                    }
                    expectedValue = 1;
                }
                obj = messages.get(++expectedValue);
            }
            messagesMap.put(session, messages);
            countersMap.put(session, expectedValue);
        }

        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];

                        if (log.isDebugEnabled()) {
                            log.debug("Source session: " + session + " - Flushing the previously queued " +
                                    "message with the sequence number: " + expectedValue);
                        }

                        try {
                            Session.sendToTarget(message, sessionID);
                        } catch (SessionNotFound ignore) { }

                        messages.remove(expectedValue);
                    }
                    expectedValue++;
                }
                messagesMap.remove(session);
                countersMap.remove(session);
            }
        }
    }