java.lang.Object
- org._3pq.jgrapht.traverse.AbstractGraphIterator
- - org._3pq.jgrapht.traverse.CrossComponentIterator
  - - org._3pq.jgrapht.traverse.BreadthFirstIterator

All Implemented Interfaces:

java.util.Iterator, GraphIterator
```
public class BreadthFirstIterator
extends CrossComponentIterator
```
A breadth-first iterator for a directed and an undirected graph. For this iterator to work correctly the graph must not be modified during iteration. Currently there are no means to ensure that, nor to fail-fast. The results of such modifications are undefined.

Since:

Jul 19, 2003

Author:

Barak Naveh

Constructor Summary

Constructors
Constructor	Description
`BreadthFirstIterator(Graph g)`	Creates a new breadth-first iterator for the specified graph.
`BreadthFirstIterator(Graph g, java.lang.Object startVertex)`	Creates a new breadth-first iterator for the specified graph.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`encounterVertex(java.lang.Object vertex, Edge edge)`	Update data structures the first time we see a vertex.
`protected void`	`encounterVertexAgain(java.lang.Object vertex, Edge edge)`	Called whenever we re-encounter a vertex.
`protected boolean`	`isConnectedComponentExhausted()`	Returns `true` if there are no more uniterated vertices in the currently iterated connected component; `false` otherwise.
`protected java.lang.Object`	`provideNextVertex()`	Returns the vertex to be returned in the following call to the iterator `next` method.

Methods inherited from class org._3pq.jgrapht.traverse.CrossComponentIterator
getSeenData, hasNext, isSeenVertex, next, putSeenData

Methods inherited from class org._3pq.jgrapht.traverse.AbstractGraphIterator
addTraversalListener, fireConnectedComponentFinished, fireConnectedComponentStarted, fireEdgeTraversed, fireVertexTraversed, 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
  - BreadthFirstIterator
```
public BreadthFirstIterator(Graph g)
```
    Creates a new breadth-first iterator for the specified graph.
    
    Parameters:
    
    g - the graph to be iterated.
  - BreadthFirstIterator
```
public BreadthFirstIterator(Graph g,
                            java.lang.Object startVertex)
```
    Creates a new breadth-first iterator for the specified graph. Iteration will start at the specified start vertex and will be limited to the connected component that includes that vertex. If the specified start vertex is null, iteration will start at an arbitrary vertex and will not be limited, that is, will be able to traverse all the graph.
    
    Parameters:
    
    g - the graph to be iterated.
    
    startVertex - the vertex iteration to be started.
- Method Detail
  - isConnectedComponentExhausted
```
protected boolean isConnectedComponentExhausted()
```
    Description copied from class: CrossComponentIterator
    
    Returns true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.
    
    Specified by:
    
    isConnectedComponentExhausted in class CrossComponentIterator
    
    Returns:
    
    true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.
    
    See Also:
    
    CrossComponentIterator.isConnectedComponentExhausted()
  - encounterVertex
```
protected void encounterVertex(java.lang.Object vertex,
                               Edge edge)
```
    Description copied from class: CrossComponentIterator
    
    Update data structures the first time we see a vertex.
    
    Specified by:
    
    encounterVertex in class CrossComponentIterator
    
    Parameters:
    
    vertex - the vertex encountered
    
    edge - the edge via which the vertex was encountered, or null if the vertex is a starting point
    
    See Also:
    
    CrossComponentIterator.encounterVertex(java.lang.Object, org._3pq.jgrapht.Edge)
  - encounterVertexAgain
```
protected void encounterVertexAgain(java.lang.Object vertex,
                                    Edge edge)
```
    Description copied from class: CrossComponentIterator
    
    Called whenever we re-encounter a vertex. The default implementation does nothing.
    
    Specified by:
    
    encounterVertexAgain in class CrossComponentIterator
    
    Parameters:
    
    vertex - the vertex re-encountered
    
    edge - the edge via which the vertex was re-encountered
    
    See Also:
    
    CrossComponentIterator.encounterVertexAgain(java.lang.Object, org._3pq.jgrapht.Edge)
  - provideNextVertex
```
protected java.lang.Object provideNextVertex()
```
    Description copied from class: CrossComponentIterator
    
    Returns the vertex to be returned in the following call to the iterator next method.
    
    Specified by:
    
    provideNextVertex in class CrossComponentIterator
    
    Returns:
    
    the next vertex to be returned by this iterator.
    
    See Also:
    
    CrossComponentIterator.provideNextVertex()

Class BreadthFirstIterator

Constructor Summary

Method Summary

Methods inherited from class org._3pq.jgrapht.traverse.CrossComponentIterator

Methods inherited from class org._3pq.jgrapht.traverse.AbstractGraphIterator

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Iterator

Constructor Detail

BreadthFirstIterator

BreadthFirstIterator

Method Detail

isConnectedComponentExhausted

encounterVertex

encounterVertexAgain

provideNextVertex