Package org.geotools.graph.traverse.standard

Class DepthFirstTopologicalIterator

  • All Implemented Interfaces:
    GraphIterator
    public class DepthFirstTopologicalIterator
extends BreadthFirstTopologicalIterator
    Iterates over the nodes of a graph in Depth First Topological Sort pattern. The following is an illustration of the iteration.


    Initially all nodes of degree less than two are active (ready to be visited). As nodes are visited, a node can become active when all but one of its related nodes have been visited ( degree = counter + 1). When a node becomes active it is placed into the active node queue (queue of nodes to be visited). The Depth First Topological iterator places nodes into the queue in Last In First Out order (a Stack).

    To determine when a node is to become active the iterator uses the counter associated with each node. If these counters are modified by an entity other then the iterator, the iteration may be affected in undefined ways.
    Author:
    Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net

    • Constructor Detail

      • DepthFirstTopologicalIterator

        public DepthFirstTopologicalIterator()

    • Method Detail

      • buildQueue

        protected Queue<Graphable> buildQueue​(Graph graph)
        Builds the active node queue.
        Overrides:
        buildQueue in class BreadthFirstTopologicalIterator
        Parameters:
        graph - The Graph whose components are being iterated over.
        Returns:
        A last in first out queue (a stack)