private static final class EndpointPairIterator.Undirected<N> extends EndpointPairIterator<N>
EndpointPairs, we keep track of the nodes that we have visited. When processing endpoint
pairs, we skip if the "other node" is in the visited set, as shown below:
Nodes = {N1, N2, N3, N4}
N2 __
/ \ | |
N1----N3 N4__|
Visited Nodes = {}
EndpointPair [N1, N2] - return
EndpointPair [N1, N3] - return
Visited Nodes = {N1}
EndpointPair [N2, N1] - skip
EndpointPair [N2, N3] - return
Visited Nodes = {N1, N2}
EndpointPair [N3, N1] - skip
EndpointPair [N3, N2] - skip
Visited Nodes = {N1, N2, N3}
EndpointPair [N4, N4] - return
Visited Nodes = {N1, N2, N3, N4}
| Modifier and Type | Field and Description |
|---|---|
private java.util.Set<N> |
visitedNodes |
node, successorIterator| Modifier | Constructor and Description |
|---|---|
private |
Undirected(Graph<N> graph) |
| Modifier and Type | Method and Description |
|---|---|
protected EndpointPair<N> |
computeNext()
Returns the next element.
|
advance, ofendOfData, hasNext, next, peekremoveprivate java.util.Set<N> visitedNodes
protected EndpointPair<N> computeNext()
AbstractIteratorAbstractIterator.endOfData() when there are no elements left in the iteration. Failure to
do so could result in an infinite loop.
The initial invocation of AbstractIterator.hasNext() or AbstractIterator.next() calls
this method, as does the first invocation of hasNext or next following each successful call to next. Once the
implementation either invokes endOfData or throws an exception,
computeNext is guaranteed to never be called again.
If this method throws an exception, it will propagate outward to the
hasNext or next invocation that invoked this method. Any
further attempts to use the iterator will result in an IllegalStateException.
The implementation of this method may not invoke the hasNext,
next, or AbstractIterator.peek() methods on this instance; if it does, an
IllegalStateException will result.
computeNext in class AbstractIterator<EndpointPair<N>>endOfData was called
during execution, the return value will be ignored.