using QuickFix;

void sendOrderCancelRequest()
{
  Message message = new Message();
  Message.Header header = message.getHeader();

  header.setField(new BeginString("FIX.4.2"));
  header.setField(new SenderCompID(TW));
  header.setField(new TargetCompID("TARGET"));
  header.setField(new MsgType("D"));
  message.setField(new OrigClOrdID("123"));
  message.setField(new ClOrdID("321"));
  message.setField(new Symbol("LNUX"));
  message.setField(new Side(Side.BUY));
  message.setField(new Text("Cancel My Order!"));

  Session.sendToTarget(message);
}