All nodes which have child catalog nodes should inherit from this package private class. In addition to the 3-phase construction interface, this abstract class adds the ability to have sub-nodes, which is provided via the resolve() and nearest() functions. The two main data members intended for inheritance are dSubNodes and sSep. If derived classes use this sub-node list and fill in their separator string the sub-node resolution can be handled by this class with out overriding resolve() and nearest().