Class ConnectivityInspector

  • All Implemented Interfaces:
    java.util.EventListener, GraphListener, VertexSetListener

    public class ConnectivityInspector
    extends java.lang.Object
    implements GraphListener
    Allows obtaining various connectivity aspects of a graph. The inspected graph is specified at construction time and cannot be modified. Currently, the inspector supports connected components for an undirected graph and weakly connected components for a directed graph. To find strongly connected components, use StrongConnectivityInspector instead.

    The inspector methods work in a lazy fashion: no computation is performed unless immediately necessary. Computation are done once and results and cached within this class for future need.

    The inspector is also a GraphListener. If added as a listener to the inspected graph, the inspector will amend internal cached results instead of recomputing them. It is efficient when a few modifications are applied to a large graph. If many modifications are expected it will not be efficient due to added overhead on graph update operations. If inspector is added as listener to a graph other than the one it inspects, results are undefined.

    Since:
    Aug 6, 2003
    Author:
    Barak Naveh, John V. Sichi
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.util.Set connectedSetOf​(java.lang.Object vertex)
      Returns a set of all vertices that are in the maximally connected component together with the specified vertex.
      java.util.List connectedSets()
      Returns a list of Sets, where each set contains all vertices that are in the same maximally connected component.
      void edgeAdded​(GraphEdgeChangeEvent e)
      Notifies that an edge has been added to the graph.
      void edgeRemoved​(GraphEdgeChangeEvent e)
      Notifies that an edge has been removed from the graph.
      boolean isGraphConnected()
      Test if the inspected graph is connected.
      boolean pathExists​(java.lang.Object sourceVertex, java.lang.Object targetVertex)
      Tests if there is a path from the specified source vertex to the specified target vertices.
      void vertexAdded​(GraphVertexChangeEvent e)
      Notifies that a vertex has been added to the graph.
      void vertexRemoved​(GraphVertexChangeEvent e)
      Notifies that a vertex has been removed from the graph.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ConnectivityInspector

        public ConnectivityInspector​(UndirectedGraph g)
        Creates a connectivity inspector for the specified undirected graph.
        Parameters:
        g - the graph for which a connectivity inspector to be created.
      • ConnectivityInspector

        public ConnectivityInspector​(DirectedGraph g)
        Creates a connectivity inspector for the specified directed graph.
        Parameters:
        g - the graph for which a connectivity inspector to be created.
    • Method Detail

      • isGraphConnected

        public boolean isGraphConnected()
        Test if the inspected graph is connected. An empty graph is not considered connected.
        Returns:
        true if and only if inspected graph is connected.
      • connectedSetOf

        public java.util.Set connectedSetOf​(java.lang.Object vertex)
        Returns a set of all vertices that are in the maximally connected component together with the specified vertex. For more on maximally connected component, see http://www.nist.gov/dads/HTML/maximallyConnectedComponent.html.
        Parameters:
        vertex - the vertex for which the connected set to be returned.
        Returns:
        a set of all vertices that are in the maximally connected component together with the specified vertex.
      • connectedSets

        public java.util.List connectedSets()
        Returns a list of Sets, where each set contains all vertices that are in the same maximally connected component. All graph vertices occur in exactly one set. For more on maximally connected component, see http://www.nist.gov/dads/HTML/maximallyConnectedComponent.html.
        Returns:
        Returns a list of Sets, where each set contains all vertices that are in the same maximally connected component.
      • pathExists

        public boolean pathExists​(java.lang.Object sourceVertex,
                                  java.lang.Object targetVertex)
        Tests if there is a path from the specified source vertex to the specified target vertices. For a directed graph, direction is ignored for this interpretation of path.

        Note: Future versions of this method might not ignore edge directions for directed graphs.

        Parameters:
        sourceVertex - one end of the path.
        targetVertex - another end of the path.
        Returns:
        true if and only if there is a path from the source vertex to the target vertex.