Examples of org.neo4j.graphdb.traversal.Evaluator

org.neo4j.graphdb.traversal.Evaluator
An Evaluator controls what's to be returned from a traversal and also how pruning is done. It looks at a {@link Path} and decides whether or not itshould be included in the traversal result. It also decides whether the traverser should continue down that path or if it should be pruned so that the traverser won't continue down that path. {@link Evaluator} and the corresponding {@link TraversalDescription#evaluator(Evaluator)}will replace {@link TraversalDescription#prune(PruneEvaluator)} and{@link TraversalDescription#filter(Predicate)} because of the flexibility andperformance improvements it can provide. @author Mattias Persson @see Evaluation @see Evaluators @see TraversalDescription#evaluator(Evaluator)

            {
                indexedRelationshipIterator = indexedRelationship.iterator();
            }


            indexedRelationshipDestinationIterator = Traversal.description().depthFirst()
                .evaluator( new Evaluator()
                {
                    @Override
                    public Evaluation evaluate( Path path )
                    {
                        if ( path.length() == 0 )

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      description = description.evaluator(evaluator);
    }
    
    // add predicates as evaluators
    for (final Predicate<Node> predicate : predicates) {
      description = description.evaluator(new Evaluator() {


        @Override
        public Evaluation evaluate(Path path) {
          Node endNode = path.endNode();
          if (predicate.evaluate(securityContext, endNode)) {

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    TraversalDescription description = StructrApp.getInstance(securityContext).getGraphDatabaseService().traversalDescription()
      .breadthFirst()
      .uniqueness(Uniqueness.NODE_RECENT)
      .evaluator(Evaluators.excludeStartPosition())
      .evaluator(new Evaluator() {


        @Override
        public Evaluation evaluate(Path path) {


          // prune path at depth maxDepth

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    return new TraversalDescriptionImpl()
        .breadthFirst()
        .relationships(
            DynamicRelationshipType.withName("HAS_FOLLOWING_INSTANCE"),
            Direction.INCOMING)
        .evaluator(new Evaluator() {
              @Override
              public Evaluation evaluate(Path path) {
                
                if (path.length() == 0) {
                  return Evaluation.EXCLUDE_AND_CONTINUE;

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        this.time = time;
    }


    public Iterable<WeightedPath> findAllPaths( Node start, final Node end )
    {
        Evaluator evaluator = new Evaluator()
        {
            public Evaluation evaluate( Path path )
            {
                if ( path.length() == 8 ) return Evaluation.EXCLUDE_AND_PRUNE;
                return ( path.endNode().equals( end ) ? Evaluation.INCLUDE_AND_PRUNE

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    Node geomNode = pipeFlow.getRecord().getGeomNode();
    Node node = geomNode.getSingleRelationship(OSMRelation.GEOM, Direction.INCOMING).getStartNode();


    TraversalDescription td = Traversal
      .description()
      .evaluator(new Evaluator() {
                @Override
                public Evaluation evaluate(Path path) {
                    if (path.length() > 0
                            && !path.relationships().iterator().next().isType(OSMRelation.NEXT)
                            && path.lastRelationship().isType(OSMRelation.NODE)) {

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    }
    
    @Test
    public void testMaxDepthAndCustomPruneEvaluatorCombined()
    {
        Evaluator lessThanThreeRels = new Evaluator()
        {
            public Evaluation evaluate( Path path )
            {
                return IteratorUtil.count( path.endNode().getRelationships( Direction.OUTGOING ).iterator() ) < 3 ?
                        Evaluation.INCLUDE_AND_PRUNE : Evaluation.INCLUDE_AND_CONTINUE;

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                new WrappedPruneEvaluator( pruning ) );
    }
    
    public TraversalDescription filter( Predicate<Path> filter )
    {
        Evaluator evaluator = null;
        if ( filter == Traversal.returnAll() )
        {
            evaluator = Evaluators.all();
        }
        else if ( filter == Traversal.returnAllButStartNode() )

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    }


    @Test
    public void testNarrowingFilters()
    {
        Evaluator mustBeConnectedToK = new MustBeConnectedToNodeFilter( getNodeWithName( "k" ) );
        Evaluator mustNotHaveMoreThanTwoOutRels = new Evaluator()
        {
            public Evaluation evaluate( Path path )
            {
                return Evaluation.ofIncludes( IteratorUtil.count( path.endNode().getRelationships( Direction.OUTGOING ) ) <= 2 );
            }

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