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

Example 1 with PathExpander

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

the class RelationshipExpanderBuilderTest method shouldInterpretNoSpecifiedRelationshipsAsAll.

@Test
public void shouldInterpretNoSpecifiedRelationshipsAsAll() throws Exception {
    // GIVEN
    Node node = createSomeData();
    PathExpander expander = RelationshipExpanderBuilder.describeRelationships(map());
    // 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()), expanded);
        tx.success();
    }
}

Example 2 with PathExpander

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

the class DijkstraBidirectional method traverser.

private Traverser traverser(Node start, final Node end, PathInterest interest) {
    final MutableDouble shortestSoFar = new MutableDouble(Double.MAX_VALUE);
    final MutableDouble startSideShortest = new MutableDouble(0);
    final MutableDouble endSideShortest = new MutableDouble(0);
    PathExpander dijkstraExpander = new DijkstraBidirectionalPathExpander(expander, shortestSoFar, true, startSideShortest, endSideShortest, epsilon);
    GraphDatabaseService db = start.getGraphDatabase();
    TraversalDescription side = db.traversalDescription().expand(dijkstraExpander, stateFactory).order(new DijkstraSelectorFactory(interest, costEvaluator)).evaluator(new DijkstraBidirectionalEvaluator(costEvaluator)).uniqueness(Uniqueness.NODE_PATH);
    TraversalDescription startSide = side;
    TraversalDescription endSide = side.reverse();
    BidirectionalTraversalDescription traversal = db.bidirectionalTraversalDescription().startSide(startSide).endSide(endSide).collisionEvaluator(Evaluators.all()).collisionPolicy(new BranchCollisionPolicy() {

        @Override
        public BranchCollisionDetector create(Evaluator evaluator, Predicate<Path> pathPredicate) {
            return new DijkstraBranchCollisionDetector(evaluator, costEvaluator, shortestSoFar, epsilon, pathPredicate);
        }
    });
    lastTraverser = traversal.traverse(start, end);
    return lastTraverser;
}

Example 3 with PathExpander

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

the class TestAStar method canUseBranchState.

@SuppressWarnings({ "rawtypes", "unchecked" })
@Test
public void canUseBranchState() throws Exception {
    // This test doesn't use the predefined finder, which only means an unnecessary instantiation
    // if such an object. And this test will be run twice (once for each finder type in data()).
    /**
         * <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>
         */
    Node nodeA = graph.makeNode("A", "x", 0d, "y", 0d);
    Node nodeB = graph.makeNode("B", "x", 2d, "y", 1d);
    Node nodeC = graph.makeNode("C", "x", 7d, "y", 0d);
    graph.makeEdge("A", "B", "length", 2d);
    graph.makeEdge("A", "B", "length", 2d);
    graph.makeEdge("B", "C", "length", 3d);
    graph.makeEdge("A", "C", "length", 10d);
    final Map<Node, Double> seenBranchStates = new HashMap<Node, Double>();
    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;
    PathFinder<WeightedPath> traversalFinder = new TraversalAStar(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);
}

Example 4 with PathExpander

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

the class PathShellApp method exec.

@Override
protected Continuation exec(AppCommandParser parser, Session session, Output out) throws Exception {
    String fromString = parser.options().get("from");
    String toString = parser.argument(0, "Must supply a 'to' node as first argument");
    String algo = parser.options().get("a");
    String maxDepthString = parser.options().get("m");
    boolean quietPrint = parser.options().containsKey("q");
    boolean caseInsensitiveFilters = parser.options().containsKey("i");
    boolean looseFilters = parser.options().containsKey("l");
    int maxDepth = maxDepthString != null ? Integer.parseInt(maxDepthString) : Integer.MAX_VALUE;
    fromString = fromString != null ? fromString : String.valueOf(this.getCurrent(session).getId());
    Map<String, Object> filter = parseFilter(parser.options().get("f"), out);
    PathExpander expander = toExpander(getServer().getDb(), Direction.BOTH, filter, caseInsensitiveFilters, looseFilters);
    PathFinder<Path> finder = expander != null ? getPathFinder(algo, expander, maxDepth, out) : null;
    if (finder != null) {
        Node fromNode = getNodeById(Long.parseLong(fromString));
        Node toNode = getNodeById(Long.parseLong(toString));
        boolean single = parser.options().containsKey("s");
        Iterable<Path> paths = single ? Arrays.asList(finder.findSinglePath(fromNode, toNode)) : finder.findAllPaths(fromNode, toNode);
        for (Path path : paths) {
            printPath(path, quietPrint, session, out);
        }
    }
    return Continuation.INPUT_COMPLETE;
}

Example 5 with PathExpander

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

the class AncestorTestCase method test.

@Test
@Graph({ "root contains child1", "child1 contains child11", "child1 contains child12", "root contains child2", "child12 contains child121", "child1 contains child13" })
public void test() {
    PathExpander expander = PathExpanders.forTypeAndDirection(Rels.contains, Direction.INCOMING);
    List<Node> nodeSet = new ArrayList<Node>();
    Map<String, Node> graph = data.get();
    nodeSet.add(graph.get("child1"));
    nodeSet.add(graph.get("root"));
    try (Transaction transaction = gdb.beginTx()) {
        Node ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("root"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("child11"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("child1"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child121"));
        nodeSet.add(graph.get("child12"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("child12"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child11"));
        nodeSet.add(graph.get("child13"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("child1"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child2"));
        nodeSet.add(graph.get("child121"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("root"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child11"));
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("child13"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("child1"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child11"));
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("child13"));
        nodeSet.add(graph.get("child121"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("child1"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child11"));
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("child13"));
        nodeSet.add(graph.get("child121"));
        nodeSet.add(graph.get("child2"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("root"), ancestor);
        nodeSet.clear();
        nodeSet.add(graph.get("child11"));
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("child13"));
        nodeSet.add(graph.get("child121"));
        nodeSet.add(graph.get("child12"));
        nodeSet.add(graph.get("root"));
        ancestor = AncestorsUtil.lowestCommonAncestor(nodeSet, expander);
        assertEquals(graph.get("root"), ancestor);
    }
}