An implementation of GraphGenerator used to generate a graph representing a
directed line network. Graphs are generated by supplying the generator with
objects of type LineSegment via the add(Object) method.
For each line segment added, an edge in the graph is created. The builder
records the end coordinates of each line added, and maintains a map of
coordinates to nodes, creating nodes when neccessary.
Edges created by the generator are of type BasicDirectedEdge and contain an
object of type LineSegment.
Nodes created by the generator are of type BasicDirectedXYNode and contain
an object of type Coordinate.
Justin Deoliveira, Refractions Research Inc, email@example.com