class RGL::DijkstraVisitor


* finish_vertex
* edge_not_relaxed
* edge_relaxed
* examine_edge
* examine_vertex
Dijkstra shortest path algorithm has the following event points:

def reset


Returns visitor into initial state. 
def reset
  super
  @distance_map = Hash.new(INFINITY)
  @parents_map  = {}
end

def set_source(source)


Initializes visitor with a new source. 
def set_source(source)
  reset
  color_map[source]    = :GRAY
  distance_map[source] = 0
end