Package com.google.common.graph
Class EndpointPairIterator.Undirected<N>
java.lang.Object
com.google.common.collect.UnmodifiableIterator<EndpointPair<N>>
com.google.common.collect.AbstractIterator<EndpointPair<N>>
com.google.common.graph.EndpointPairIterator<N>
com.google.common.graph.EndpointPairIterator.Undirected<N>
- All Implemented Interfaces:
Iterator<EndpointPair<N>>
- Enclosing class:
EndpointPairIterator<N>
If the graph is undirected, each unordered [node, otherNode] pair (except self-loops) will be
visited twice if there is an edge connecting them. To avoid returning duplicate
EndpointPair
s, 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}
-
Field Summary
FieldsFields inherited from class com.google.common.graph.EndpointPairIterator
node, successorIterator
-
Constructor Summary
Constructors -
Method Summary
Methods inherited from class com.google.common.graph.EndpointPairIterator
advance, of
Methods inherited from class com.google.common.collect.AbstractIterator
endOfData, hasNext, next, peek
Methods inherited from class com.google.common.collect.UnmodifiableIterator
remove
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
-
Field Details
-
visitedNodes
-
-
Constructor Details
-
Undirected
-
-
Method Details
-
computeNext
Description copied from class:AbstractIterator
Returns the next element. Note: the implementation must callAbstractIterator.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()
orAbstractIterator.next()
calls this method, as does the first invocation ofhasNext
ornext
following each successful call tonext
. Once the implementation either invokesendOfData
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
ornext
invocation that invoked this method. Any further attempts to use the iterator will result in anIllegalStateException
.The implementation of this method may not invoke the
hasNext
,next
, orAbstractIterator.peek()
methods on this instance; if it does, anIllegalStateException
will result.- Specified by:
computeNext
in classAbstractIterator<EndpointPair<N>>
- Returns:
- the next element if there was one. If
endOfData
was called during execution, the return value will be ignored.
-