org.jgrapht.traverse

Class CrossComponentIterator<V,E,D>

java.lang.Object

org.jgrapht.traverse.AbstractGraphIterator<V,E>

org.jgrapht.traverse.CrossComponentIterator<V,E,D>

Type Parameters:

V - vertex type

E - edge type

D - type of data associated to seen vertices

All Implemented Interfaces:

Iterator<V>, GraphIterator<V,E>

Direct Known Subclasses:

BreadthFirstIterator, ClosestFirstIterator, DepthFirstIterator

public abstract class CrossComponentIterator<V,E,D>
extends AbstractGraphIterator<V,E>

Provides a cross-connected-component traversal functionality for iterator subclasses.

Author:

Barak Naveh

Field Summary

Fields inherited from class org.jgrapht.traverse.AbstractGraphIterator

crossComponentTraversal, graph, nListeners, reusableEdgeEvent, reusableVertexEvent, reuseEvents

Constructor Summary

Constructors

Constructor and Description
CrossComponentIterator(Graph<V,E> g) Creates a new iterator for the specified graph.
CrossComponentIterator(Graph<V,E> g, Iterable<V> startVertices) Creates a new iterator for the specified graph.
CrossComponentIterator(Graph<V,E> g, V startVertex) Creates a new iterator for the specified graph.

Method Summary

Modifier and Type	Method and Description
protected abstract void	encounterVertex(V vertex, E edge) Update data structures the first time we see a vertex.
protected abstract void	encounterVertexAgain(V vertex, E edge) Called whenever we re-encounter a vertex.
protected void	finishVertex(V vertex) Called when a vertex has been finished (meaning is dependent on traversal represented by subclass).
protected Iterator<V>	getEntireGraphVertexIterator() Lazily instantiates entireGraphVertexIterator.
protected D	getSeenData(V vertex) Access the data stored for a seen vertex.
boolean	hasNext()
protected abstract boolean	isConnectedComponentExhausted() Returns true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.
protected boolean	isSeenVertex(V vertex) Determines whether a vertex has been seen yet by this traversal.
V	next()
protected abstract V	provideNextVertex() Returns the vertex to be returned in the following call to the iterator next method.
protected D	putSeenData(V vertex, D data) Stores iterator-dependent data for a vertex that has been seen.

Methods inherited from class org.jgrapht.traverse.AbstractGraphIterator

addTraversalListener, createEdgeTraversalEvent, createVertexTraversalEvent, fireConnectedComponentFinished, fireConnectedComponentStarted, fireEdgeTraversed, fireVertexFinished, fireVertexTraversed, getGraph, isCrossComponentTraversal, isReuseEvents, remove, removeTraversalListener, setCrossComponentTraversal, setReuseEvents

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

CrossComponentIterator

public CrossComponentIterator(Graph<V,E> g)

Creates a new iterator for the specified graph.

Parameters:

g - the graph to be iterated

CrossComponentIterator

public CrossComponentIterator(Graph<V,E> g,
                              V startVertex)

Creates a new iterator for the specified graph. Iteration will start at the specified start vertex. If the specified start vertex is null, Iteration will start at an arbitrary graph vertex.

Parameters:

g - the graph to be iterated.

startVertex - the vertex iteration to be started.

Throws:

IllegalArgumentException - if g==null or does not contain startVertex

CrossComponentIterator

public CrossComponentIterator(Graph<V,E> g,
                              Iterable<V> startVertices)

Creates a new iterator for the specified graph. Iteration will start at the specified start vertices. If the specified start vertices is null, Iteration will start at an arbitrary graph vertex.

Parameters:

g - the graph to be iterated.

startVertices - the vertices iteration to be started.

Throws:

IllegalArgumentException - if g==null or does not contain startVertex

Method Detail

hasNext

public boolean hasNext()

next

public V next()

getEntireGraphVertexIterator

protected Iterator<V> getEntireGraphVertexIterator()

Lazily instantiates entireGraphVertexIterator.

Returns:

iterator which provides start vertices for cross-component iteration

isConnectedComponentExhausted

protected abstract boolean isConnectedComponentExhausted()

Returns true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.

Returns:

true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.

encounterVertex

protected abstract void encounterVertex(V vertex,
                                        E edge)

Update data structures the first time we see a vertex.

Parameters:

vertex - the vertex encountered

edge - the edge via which the vertex was encountered, or null if the vertex is a starting point

provideNextVertex

protected abstract V provideNextVertex()

Returns the vertex to be returned in the following call to the iterator next method.

Returns:

the next vertex to be returned by this iterator.

getSeenData

protected D getSeenData(V vertex)

Access the data stored for a seen vertex.

Parameters:

vertex - a vertex which has already been seen.

Returns:

data associated with the seen vertex or null if no data was associated with the vertex. A null return can also indicate that the vertex was explicitly associated with null.

isSeenVertex

protected boolean isSeenVertex(V vertex)

Determines whether a vertex has been seen yet by this traversal.

Parameters:

vertex - vertex in question

Returns:

true if vertex has already been seen

encounterVertexAgain

protected abstract void encounterVertexAgain(V vertex,
                                             E edge)

Called whenever we re-encounter a vertex. The default implementation does nothing.

Parameters:

vertex - the vertex re-encountered

edge - the edge via which the vertex was re-encountered

putSeenData

protected D putSeenData(V vertex,
                        D data)

Stores iterator-dependent data for a vertex that has been seen.

Parameters:

vertex - a vertex which has been seen.

data - data to be associated with the seen vertex.

Returns:

previous value associated with specified vertex or null if no data was associated with the vertex. A null return can also indicate that the vertex was explicitly associated with null.

finishVertex

protected void finishVertex(V vertex)

Called when a vertex has been finished (meaning is dependent on traversal represented by subclass).

Parameters:

vertex - vertex which has been finished