+/** XLineFactory is used to generate an XLine pointer, given just the
+ * pattern, timing information and type of line to create. This is used
+ * for example in the spanningtree module which will call an XLineFactory
+ * to create a new XLine when it is inbound on a server link, so that it
+ * does not have to know the specifics of the internals of an XLine class
+ * and/or how to call its constructor.
+ */
+class CoreExport XLineFactory : public classbase