public override Node Next()
{
if (!HasNext())
{
throw new NoSuchElementException();
}
Node currentNode = Queue.extractMin();
CostType currentCost = MySeen[currentNode];
// Already done with this node?
if (MyDistances.ContainsKey(currentNode))
{
return(null);
}
if (outerInstance.LimitReached())
{
return(null);
}
++outerInstance.NumberOfNodesTraversed;
MyDistances[currentNode] = currentCost;
// TODO: remove from seen or not? probably not... because of path
// detection
// Check if we have found a better path
CheckForPath(currentNode, currentCost, OtherSeen);
// Found a path? (abort traversing from this node)
if (OtherDistances.ContainsKey(currentNode))
{
OneShortestPathHasBeenFound = true;
}
else
{
// Otherwise, follow all edges from this node
foreach (RelationshipType costRelationType in outerInstance.CostRelationTypes)
{
ResourceIterable <Relationship> relationships = Iterables.asResourceIterable(currentNode.GetRelationships(costRelationType, Direction));
using (ResourceIterator <Relationship> iterator = relationships.GetEnumerator())
{
while (iterator.MoveNext())
{
Relationship relationship = iterator.Current;
if (outerInstance.LimitReached())
{
break;
}
++outerInstance.NumberOfTraversedRelationShips;
// Target node
Node target = relationship.GetOtherNode(currentNode);
if (OtherDistances.ContainsKey(target))
{
continue;
}
// Find out if an eventual path would go in the opposite
// direction of the edge
bool backwardsEdge = relationship.EndNode.Equals(currentNode) ^ Backwards;
CostType newCost = outerInstance.CostAccumulator.addCosts(currentCost, outerInstance.CostEvaluator.getCost(relationship, backwardsEdge ? Direction.INCOMING : Direction.OUTGOING));
// Already done with target node?
if (MyDistances.ContainsKey(target))
{
// Have we found a better cost for a node which is
// already
// calculated?
if (outerInstance.CostComparator.Compare(MyDistances[target], newCost) > 0)
{
throw new Exception("Cycle with negative costs found.");
}
// Equally good path found?
else if (outerInstance.CalculateAllShortestPaths && outerInstance.CostComparator.Compare(MyDistances[target], newCost) == 0)
{
// Put it in predecessors
IList <Relationship> myPredecessors = Predecessors[currentNode];
// Dont do it if this relation is already in
// predecessors (other direction)
if (myPredecessors == null || !myPredecessors.Contains(relationship))
{
IList <Relationship> predList = Predecessors[target];
if (predList == null)
{
// This only happens if we get back to
// the
// start node, which is just bogus
}
else
{
predList.Add(relationship);
}
}
}
continue;
}
// Have we found a better cost for this node?
if (!MySeen.ContainsKey(target) || outerInstance.CostComparator.Compare(MySeen[target], newCost) > 0)
{
// Put it in the queue
if (!MySeen.ContainsKey(target))
{
Queue.insertValue(target, newCost);
}
// or update the entry. (It is important to keep
// these
// cases apart to limit the size of the queue)
else
{
Queue.decreaseValue(target, newCost);
}
// Update it
MySeen[target] = newCost;
// Put it in predecessors
IList <Relationship> predList = new LinkedList <Relationship>();
predList.Add(relationship);
Predecessors[target] = predList;
}
// Have we found an equal cost for (additional path to)
// this
// node?
else if (outerInstance.CalculateAllShortestPaths && outerInstance.CostComparator.Compare(MySeen[target], newCost) == 0)
{
// Put it in predecessors
IList <Relationship> predList = Predecessors[target];
predList.Add(relationship);
}
}
}
}
}
// Check how far we need to continue when searching for all shortest
// paths
if (outerInstance.CalculateAllShortestPaths && OneShortestPathHasBeenFound)
{
// If we cannot continue or continuation would only find more
// expensive paths: conclude that all shortest paths have been
// found.
AllShortestPathsHasBeenFound = Queue.Empty || outerInstance.CostComparator.Compare(MySeen[Queue.peek()], currentCost) > 0;
}
return(currentNode);
}
internal virtual IList <object> GetObjectsAsList(ResourceIterator <IDictionary <string, object> > r, string key)
{
return(r.Select(s => s.get(key)).ToList());
}
internal virtual void AssertKeyIs(ResourceIterator <IDictionary <string, object> > r, string key, params object[] items)
{
AssertKeyIsArray(r, key, items);
}
private ISet <string> GetFileNames(ResourceIterator <File> files)
{
//JAVA TO C# CONVERTER TODO TASK: Most Java stream collectors are not converted by Java to C# Converter:
return(Files.Select(File.getAbsolutePath).Where(this.segmentsFilePredicate).collect(Collectors.toSet()));
}
//JAVA TO C# CONVERTER WARNING: 'final' parameters are ignored unless the option to convert to C# 7.2 'in' parameters is selected:
//ORIGINAL LINE: public static <T> org.neo4j.graphdb.ResourceIterable<T> asResourceIterable(final org.neo4j.graphdb.ResourceIterator<T> it)
public static ResourceIterable <T> AsResourceIterable <T>(ResourceIterator <T> it)
{
return(() => it);
}
private void AssertKeyIs(ResourceIterator <IDictionary <string, object> > r, string key, params string[] items)
{
AssertKeyIsArray(r, key, items);
}
public MappingResourceIteratorAnonymousInnerClass(ResourceIterableWrapper <T, U> outerInstance, ResourceIterator <U> iterator) : base(iterator)
{
this.outerInstance = outerInstance;
}
public MappingResourceIteratorAnonymousInnerClass(NodeExpansion outerInstance, ResourceIterator <Relationship> doExpand, Node node) : base(doExpand)
{
this.outerInstance = outerInstance;
this._node = node;
}
public MappingResourceIterator(ResourceIterator <S> sourceResourceIterator)
{
this._sourceIterator = sourceResourceIterator;
}
internal virtual void AssertEmpty(ResourceIterator <R> iterator)
{
//JAVA TO C# CONVERTER TODO TASK: Java iterators are only converted within the context of 'while' and 'for' loops:
assertFalse("no more", iterator.hasNext());
}
/// <summary>
/// Instantiates a new limiting iterator which iterates over {@code source}
/// and if {@code limit} items have been returned the next <seealso cref="hasNext()"/>
/// will return {@code false}.
/// </summary>
/// <param name="source"> the source of items. </param>
/// <param name="limit"> the limit, i.e. the max number of items to return. </param>
public LimitingResourceIterator(ResourceIterator <T> source, int limit)
{
this._source = source;
this._limit = limit;
}
public PrefetchingResourceIteratorAnonymousInnerClass(ResourcePathIterableWrapperAnonymousInnerClass2 outerInstance, ResourceIterator <Path> pathIterator)
{
this.outerInstance = outerInstance;
this._pathIterator = pathIterator;
}
private void GetSnapshotFilesMetadata(ResourceIterator <File> snapshot, ICollection <StoreFileMetadata> targetFiles)
{
snapshot.Select(_toStoreFileMetatadata).ForEach(targetFiles.add);
}
internal ExceptionConversion(ResourceIterator <T> inner)
{
this.Inner = inner;
}
