Examples with PathExpander org.neo4j.graphdb.PathExpander used on opensource projects

Example 6 with PathExpander

use of org.neo4j.graphdb.PathExpander in project neo4j by neo4j.

the class DatabaseActions method getNodeRelationships.

@SuppressWarnings("unchecked")
public ListRepresentation getNodeRelationships(long nodeId, RelationshipDirection direction, Collection<String> types) throws NodeNotFoundException {
    Node node = node(nodeId);
    PathExpander expander;
    if (types.isEmpty()) {
        expander = PathExpanders.forDirection(direction.internal);
    } else {
        PathExpanderBuilder builder = PathExpanderBuilder.empty();
        for (String type : types) {
            builder = builder.add(RelationshipType.withName(type), direction.internal);
        }
        expander = builder.build();
    }
    return RelationshipRepresentation.list(expander.expand(Paths.singleNodePath(node), BranchState.NO_STATE));
}

Example 7 with PathExpander

use of org.neo4j.graphdb.PathExpander in project neo4j by neo4j.

the class RelationshipExpanderBuilderTest method shouldInterpretSomeSpecifiedRelationships.

@Test
public void shouldInterpretSomeSpecifiedRelationships() throws Exception {
    // GIVEN
    Node node = createSomeData();
    PathExpander expander = RelationshipExpanderBuilder.describeRelationships(map("relationships", map("type", MyRelTypes.TEST.name(), "direction", RelationshipDirection.out.name())));
    // WHEN
    Set<Relationship> expanded;
    try (Transaction tx = db.beginTx()) {
        expanded = asSet(expander.expand(singleNodePath(node), NO_STATE));
        tx.success();
    }
    try (Transaction tx = db.beginTx()) {
        // THEN
        assertEquals(asSet(node.getRelationships(MyRelTypes.TEST)), expanded);
        tx.success();
    }
}

Example 8 with PathExpander

use of org.neo4j.graphdb.PathExpander in project neo4j by neo4j.

the class TestOrderByTypeExpander method evenDifferentDirectionsKeepsOrder.

@Test
void evenDifferentDirectionsKeepsOrder() {
    PathExpander expander = new OrderedByTypeExpander().add(next, INCOMING).add(firstComment).add(comment).add(next, OUTGOING);
    try (Transaction transaction = beginTx()) {
        Iterator<Node> itr = transaction.traversalDescription().depthFirst().expand(expander).traverse(transaction.getNodeById(node("A2").getId())).nodes().iterator();
        assertOrder(transaction, itr, "A2", "A1", "C1", "C2", "C3", "C4", "C5", "C6", "A3", "C7", "C8", "C9");
    }
}

Example 9 with PathExpander

use of org.neo4j.graphdb.PathExpander in project neo4j by neo4j.

the class TestOrderByTypeExpander method makeSureNodesAreTraversedInCorrectOrder.

@Test
void makeSureNodesAreTraversedInCorrectOrder() {
    try (Transaction transaction = beginTx()) {
        PathExpander expander = new OrderedByTypeExpander().add(firstComment).add(comment).add(next);
        Iterator<Node> itr = transaction.traversalDescription().depthFirst().expand(expander).traverse(transaction.getNodeById(node("A1").getId())).nodes().iterator();
        assertOrder(transaction, itr, "A1", "C1", "C2", "C3", "A2", "C4", "C5", "C6", "A3", "C7", "C8", "C9");
        expander = new OrderedByTypeExpander().add(next).add(firstComment).add(comment);
        itr = transaction.traversalDescription().depthFirst().expand(expander).traverse(transaction.getNodeById(node("A1").getId())).nodes().iterator();
        assertOrder(transaction, itr, "A1", "A2", "A3", "C7", "C8", "C9", "C4", "C5", "C6", "C1", "C2", "C3");
    }
}

Example 10 with PathExpander

use of org.neo4j.graphdb.PathExpander in project neo4j by neo4j.

the class TestAStar method canUseBranchState.

@SuppressWarnings({ "rawtypes", "unchecked" })
@ParameterizedTest
@MethodSource("params")
void canUseBranchState(Function<EvaluationContext, PathFinder<WeightedPath>> finderFactory) {
    /**
     * <pre>
     *   012345    A - B:  2
     *  +------>y  A - B:  2
     * 0|A         B - C:  3
     * 1|          A - C:  10
     * 2| B
     * 3|
     * 4|
     * 5|
     * 6|
     * 7|C
     *  V
     *  x
     *
     * </pre>
     */
    try (Transaction transaction = graphDb.beginTx()) {
        Node nodeA = graph.makeNode(transaction, "A", "x", 0d, "y", 0d);
        Node nodeB = graph.makeNode(transaction, "B", "x", 2d, "y", 1d);
        Node nodeC = graph.makeNode(transaction, "C", "x", 7d, "y", 0d);
        graph.makeEdge(transaction, "A", "B", "length", 2d);
        graph.makeEdge(transaction, "A", "B", "length", 2d);
        graph.makeEdge(transaction, "B", "C", "length", 3d);
        graph.makeEdge(transaction, "A", "C", "length", 10d);
        final Map<Node, Double> seenBranchStates = new HashMap<>();
        PathExpander<Double> expander = new PathExpander<Double>() {

            @Override
            public Iterable<Relationship> expand(Path path, BranchState<Double> state) {
                double newState = state.getState();
                if (path.length() > 0) {
                    newState += (Double) path.lastRelationship().getProperty("length");
                    state.setState(newState);
                }
                seenBranchStates.put(path.endNode(), newState);
                return path.endNode().getRelationships(OUTGOING);
            }

            @Override
            public PathExpander<Double> reverse() {
                throw new UnsupportedOperationException();
            }
        };
        double initialStateValue = 0D;
        var context = new BasicEvaluationContext(transaction, graphDb);
        PathFinder<WeightedPath> traversalFinder = new TraversalAStar<>(context, expander, new InitialBranchState.State(initialStateValue, initialStateValue), doubleCostEvaluator("length"), ESTIMATE_EVALUATOR);
        WeightedPath path = traversalFinder.findSinglePath(nodeA, nodeC);
        assertEquals((Double) 5.0D, (Double) path.weight());
        assertPathDef(path, "A", "B", "C");
        assertEquals(MapUtil.<Node, Double>genericMap(nodeA, 0D, nodeB, 2D), seenBranchStates);
        transaction.commit();
    }
}