Package org.jgrapht.alg.connectivity
Class ConnectivityInspector<V,E>
 java.lang.Object

 org.jgrapht.alg.connectivity.ConnectivityInspector<V,E>

 Type Parameters:
V
 the graph vertex typeE
 the graph edge type
 All Implemented Interfaces:
EventListener
,GraphListener<V,E>
,VertexSetListener<V>
public class ConnectivityInspector<V,E> extends Object implements GraphListener<V,E>
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, useKosarajuStrongConnectivityInspector
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. Author:
 Barak Naveh, John V. Sichi


Constructor Summary
Constructors Constructor Description ConnectivityInspector(Graph<V,E> g)
Creates a connectivity inspector for the specified graph.

Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Set<V>
connectedSetOf(V vertex)
Returns a set of all vertices that are in the maximally connected component together with the specified vertex.List<Set<V>>
connectedSets()
Returns a list ofSet
s, where each set contains all vertices that are in the same maximally connected component.void
edgeAdded(GraphEdgeChangeEvent<V,E> e)
Notifies that an edge has been added to the graph.void
edgeRemoved(GraphEdgeChangeEvent<V,E> e)
Notifies that an edge has been removed from the graph.boolean
isConnected()
Test if the inspected graph is connected.boolean
pathExists(V sourceVertex, V targetVertex)
Tests whether two vertices lay respectively in the same connected component (undirected graph), or in the same weakly connected component (directed graph).void
vertexAdded(GraphVertexChangeEvent<V> e)
Notifies that a vertex has been added to the graph.void
vertexRemoved(GraphVertexChangeEvent<V> 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

Methods inherited from interface org.jgrapht.event.GraphListener
edgeWeightUpdated




Method Detail

isConnected
public boolean isConnected()
Test if the inspected graph is connected. A graph is connected when there is a path between every pair of vertices. In a connected graph, there are no unreachable vertices. When the inspected graph is a directed graph, this method returns true if and only if the inspected graph is weakly connected. An empty graph is not considered connected. Returns:
true
if and only if inspected graph is connected.

connectedSetOf
public Set<V> connectedSetOf(V 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 List<Set<V>> connectedSets()
Returns a list ofSet
s, 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
Set
s, where each set contains all vertices that are in the same maximally connected component.

edgeAdded
public void edgeAdded(GraphEdgeChangeEvent<V,E> e)
Description copied from interface:GraphListener
Notifies that an edge has been added to the graph. Specified by:
edgeAdded
in interfaceGraphListener<V,E>
 Parameters:
e
 the edge event. See Also:
GraphListener.edgeAdded(GraphEdgeChangeEvent)

edgeRemoved
public void edgeRemoved(GraphEdgeChangeEvent<V,E> e)
Description copied from interface:GraphListener
Notifies that an edge has been removed from the graph. Specified by:
edgeRemoved
in interfaceGraphListener<V,E>
 Parameters:
e
 the edge event. See Also:
GraphListener.edgeRemoved(GraphEdgeChangeEvent)

pathExists
public boolean pathExists(V sourceVertex, V targetVertex)
Tests whether two vertices lay respectively in the same connected component (undirected graph), or in the same weakly connected component (directed graph). Parameters:
sourceVertex
 one end of the path.targetVertex
 another end of the path. Returns:
true
if and only if the source and target vertex are in the same connected component (undirected graph), or in the same weakly connected component (directed graph).

vertexAdded
public void vertexAdded(GraphVertexChangeEvent<V> e)
Description copied from interface:VertexSetListener
Notifies that a vertex has been added to the graph. Specified by:
vertexAdded
in interfaceVertexSetListener<V>
 Parameters:
e
 the vertex event. See Also:
VertexSetListener.vertexAdded(GraphVertexChangeEvent)

vertexRemoved
public void vertexRemoved(GraphVertexChangeEvent<V> e)
Description copied from interface:VertexSetListener
Notifies that a vertex has been removed from the graph. Specified by:
vertexRemoved
in interfaceVertexSetListener<V>
 Parameters:
e
 the vertex event. See Also:
VertexSetListener.vertexRemoved(GraphVertexChangeEvent)

