Mattias,
Ok well, after a little bit of greymatter work, I finally got it.
I didn't realized that links provides reachability of the nodes, not
"filtering" of the nodes.
Since all nodes are linked to a root node, i can reach all nodes by
traversing from rootnode only on CONTAINS links.
I have then to "filter" nodes depending on interesting attributes...
The following code does what I want.
final int sOffset = 3;
Traverser friendsTraverser = world.traverse(
Traverser.Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
new ReturnableEvaluator() {
public boolean isReturnableNode(TraversalPosition pos) {
boolean atLeastAnIncomingKnowsBoundedLink = false;
boolean atLeastAnOutgoingKnowsBoundedLink = false;
Iterator allOutRels =
pos.currentNode().getRelationships(Direction.OUTGOING).iterator();
while (allOutRels.hasNext()) {
Relationship object = (Relationship)
allOutRels.next();
if(((Integer)object.getProperty("beginDateOffset")) >= sOffset){
atLeastAnOutgoingKnowsBoundedLink |=
true;
}
}
Iterator allInRels =
pos.currentNode().getRelationships(Direction.INCOMING).iterator();
while (allInRels.hasNext()) {
Relationship object = (Relationship)
allInRels.next();
if(((Integer)object.getProperty("beginDateOffset")) >= sOffset){
atLeastAnIncomingKnowsBoundedLink |=
true;
}
}
return atLeastAnIncomingKnowsBoundedLink ||
atLeastAnOutgoingKnowsBoundedLink;
}
},
MyRelationshipTypes.CONTAINS,
Direction.OUTGOING);
Since I can reach all nodes with CONTAINS link type, I doesn't need to
'traverse' the other type like I've naively done before.
I tried various values for the links properties, and the result is OK !
On top of that, I would add a subsidiary question : is my solution not
performance killer ? Iterating through all incoming and outgoing links from
a node is not overkill ?
Thank you in advance,
Best regards,
sni.
2009/7/31 <[email protected]>
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> 1. Re: Searching 'links', based on their attributes ?
> (Mattias Persson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 31 Jul 2009 10:50:24 +0200
> From: Mattias Persson <[email protected]>
> Subject: Re: [Neo] Searching 'links', based on their attributes ?
> To: Neo user discussions <[email protected]>
> Message-ID:
> <[email protected]>
> Content-Type: text/plain; charset=UTF-8
>
> Hi Sebastian,
>
> I'm not sure I really grasp your problem, but one solution that seems
> appropriate would be to connect all those object graphs to one "super
> root node" of your choice. So that you create this super root node,
> maybe connect it to the neo reference node and let all your object
> graphs have some relationship to that super root node. That way
> they'll all be connected in a way and you could have that node as a
> starting node when you traverse.
>
> Alternatively you could connect all your object graphs to the neo
> reference node directly and use that as a starting point for your
> traversals.
>
> Would that help you?
>
> 2009/7/31 sebastien nichele <[email protected]>:
> > Hi,
> >
> > I'm currently evaluating neo4j and I'am really satisfied/impressed by it.
> >
> > However, I'm asking myself several questions.
> >
> > In my "node space" I have several dissocied objects graphs.
> > Links between nodes bears two attributes "startDate" and "endDate".
> >
> > ?At one time, i want to display all nodes in my graph that have links
> > ?that match some combinations of startDate and endDate (ie. 'give me all
> > nodes linked by links that
> > ?have dates between 1st january and 3 march'), whatever the link nature
> is.
> >
> > ?I started using traversing for that, using exemples I found on
> > documentation.
> > ?My problem is that I don't have any "super root node" in my "node space"
> to
> > start traversing (since traversing needs a 'root' node), but several
> graphs
> > with several root nodes.
> >
> > ?In realize that in fact, I don't really want to "traverse" a graph, but
> > simply pick links based on their attributes, and then, return nodes on
> links
> > sides.
> >
> > ?I digged upon the documentation, but didn't find a way to do that simply
> > and efficiently.
> >
> > ?I have the feeling that I am missing something...
> >
> > ?Can anyone shed some light on my matter ? ;)
> >
> > ?Thanks in advance for your answers,
> >
> > ?Best regards,
> >
> > ?sni.
> > _______________________________________________
> > Neo mailing list
> > [email protected]
> > https://lists.neo4j.org/mailman/listinfo/user
> >
>
>
>
> --
> Mattias Persson, [[email protected]]
> Neo Technology, www.neotechnology.com
>
>
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