This class represents an abstract graph of LayeredDigraphVertexes and LayeredDigraphEdges
that can be constructed based on the Nodes and Links of a Diagram
so that the LayeredDigraphLayout can operate independently of the diagram until it
is time to commit any node positioning or link routing.
This constructs an empty network.
It is commonplace to call addParts to build up the network
to have the same structure as a Diagram's or Group's nodes and links.
This class represents an abstract graph of LayeredDigraphVertexes and LayeredDigraphEdges that can be constructed based on the Nodes and Links of a Diagram so that the LayeredDigraphLayout can operate independently of the diagram until it is time to commit any node positioning or link routing.
This class inherits from LayoutNetwork.