As Node type is based very close to object oriented concepts - you can convert/cast nodes on type hierarchy.

The Higher element on a Node Type Hierarchy should be annotated with SLDefineHierarchy, wich tells to OpenSpotLigth graph that this NodeType defines a family of data (ie. JavaType -> JavaClassType, JavaEnumType, ...).

The general idea of this algorith is: Create a hash number based on TypeName and, as more specific is the type, its add one into this number.

Important Note: This algorithm is crucial to help implement the node id - an identifier that enables query a node based on its type (hierarchy), parent and name.