In case you are interested, I implemented cycle detection by using
Tarjan algorithm, not the traversal.
The code is visible in the Italian Wikipedia, I hope it's intelligible
although the language.
http://it.wikipedia.org/wiki/Algoritmo_di_Tarjan_per_le_componenti_fortemente_connesse#Implementazione_in_Java
Hi
Jacopo Farina
Il giorno ven, 25/03/2011 alle 13.51 +0100, Mattias Persson ha scritto:
> I think you could implement this using RELATIONSHIP_GLOBAL uniqueness, like
> (from the top of my head):
>
> Traversal.description().uniqueness( Uniqueness.RELATIONSHIP_GLOBAL )
> .evaluator(new Evaluator() {
> public Evaluation(Path path) {
> return path.length() > 0 && endNodeOccursPreviouslyInPath(
> path ) ?
> Evaluation.INCLUDE_AND_CONTINUE :
> Evaluation.EXCLUDE_AND_CONTINUE;
> }
>
> private boolean endNodeOccursPreviouslyInPath(Path path) {
> Node endNode = path.endNode();
> int counter = 0;
> for ( Node node : path.nodes() ) {
> if ( counter++ < path.length() && node.equals( endNode ) )
> return true;
> }
> return false;
> }
> } ).traverse(...);
>
> This should (if it even compiles :) ) return paths containing cycles.
> Something like this you're looking for?
>
> 2011/3/25 Wouter De Borger <w.debor...@gmail.com>
>
> > Hi all,
> >
> > I would like to detect all cycles in a traversal.
> >
> > I know the traversal framework has cycle avoidance built-in, but there
> > doesn't seem to be an API for cycle detection!
> >
> > Has anyone already implemented a cycle detector for traversals?
> >
> > Thanks in advance,
> > Wouter
> > _______________________________________________
> > Neo4j mailing list
> > User@lists.neo4j.org
> > https://lists.neo4j.org/mailman/listinfo/user
> >
>
>
>
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