无法将quickfix.Message强制转换为quickfix.fix50sp2.Message

Question

I'm using the latest quickfix version which is 1.6.0. I already have code which is written against 1.5.3 and what I'm trying to do is upgrade that to 1.6.0

The problem I have is when I use the crack(msg,sessionID) method it throws quickfix.Message cannot be cast to quickfix.fix50sp2.Message error. I'm sending a correct FIX50SP2 MarketDataSnapshotFullRefresh message from verifix. An extract of the exception is below

java.lang.ClassCastException: quickfix.Message cannot be cast to quickfix.fix50sp2.Message at quickfix.fix50sp2.MessageCracker.crack(MessageCracker.java:1555) at com.****.fixserver.FixMessageListener.fromApp(FixMessageListener.java:162) at quickfix.Session.fromCallback(Session.java:1731) at quickfix.Session.verify(Session.java:1682)

How can I crack the incoming message to the correct SP2 message?

There is a crack50() method, but that requires a SP2 message which is unavailable in the fromApp callback.

Answer 1

When the begin string is FIXT.1.1 quickfix will treat the message as FIX50 with the DefaultMessageFactory . So it will automatically generate a FIX.5.0 message.

The resolution is to write your own custom message factory to generate a SP2 message when the transport is FIXT.1.1. Here's how I did it.

Write a custom message factory implementing quickfix.MessageFactory interface. You can copy the DefaultMessageFactory code and change the create() method as follows.

 public Message create(String beginString, String msgType) {
    MessageFactory messageFactory = messageFactories.get(beginString);
    if (beginString.equals(BEGINSTRING_FIXT11)) {
        // The default message factory assumes that only FIX 5.0 will be
        // used with FIXT 1.1 sessions. A more flexible approach will require
        // an extension to the QF JNI API. Until then, you will need a custom
        // message factory if you want to use application messages prior to
        // FIX 5.0 with a FIXT 1.1 session.
        //
        // TODO: how do we support 50/50SP1/50SP2 concurrently?
        //
        // If you need to determine admin message category based on a data
        // dictionary, then use a custom message factory and don't use the
        // static method used below.
        if (!MessageUtils.isAdminMessage(msgType)) {
            messageFactory = messageFactories.get(FIX50SP2);
        }
    }

    if (messageFactory != null) {
        return messageFactory.create(beginString, msgType);
    }

    Message message = new Message();
    message.getHeader().setString(MsgType.FIELD, msgType);

    return message;
}