@Test
public void canGetMultiplePathsInTriangleGraph() throws Exception {
Node nodeA = graph.makeNode("A");
Node nodeB = graph.makeNode("B");
Node nodeC = graph.makeNode("C");
Set<Relationship> expectedFirsts = new HashSet<Relationship>();
expectedFirsts.add(graph.makeEdge("A", "B", "length", 1d));
expectedFirsts.add(graph.makeEdge("A", "B", "length", 1d));
Relationship expectedSecond = graph.makeEdge("B", "C", "length", 2d);
graph.makeEdge("A", "C", "length", 5d);
Dijkstra algo =
new Dijkstra(
PathExpanders.allTypesAndDirections(), CommonEvaluators.doubleCostEvaluator("length"));
Iterator<WeightedPath> paths = algo.findAllPaths(nodeA, nodeC).iterator();
for (int i = 0; i < 2; i++) {
assertTrue("expected more paths", paths.hasNext());
Path path = paths.next();
assertPath(path, nodeA, nodeB, nodeC);
Iterator<Relationship> relationships = path.relationships().iterator();
assertTrue("found shorter path than expected", relationships.hasNext());
assertTrue(
"path contained unexpected relationship", expectedFirsts.remove(relationships.next()));
assertTrue("found shorter path than expected", relationships.hasNext());
assertEquals(expectedSecond, relationships.next());
assertFalse("found longer path than expected", relationships.hasNext());
}
assertFalse("expected at most two paths", paths.hasNext());
}
@Test
public void canGetPathsInTriangleGraph() throws Exception {
Node nodeA = graph.makeNode("A");
Node nodeB = graph.makeNode("B");
Node nodeC = graph.makeNode("C");
graph.makeEdge("A", "B", "length", 2d);
graph.makeEdge("B", "C", "length", 3d);
graph.makeEdge("A", "C", "length", 10d);
Dijkstra algo =
new Dijkstra(
PathExpanders.allTypesAndDirections(), CommonEvaluators.doubleCostEvaluator("length"));
Iterator<WeightedPath> paths = algo.findAllPaths(nodeA, nodeC).iterator();
assertTrue("expected at least one path", paths.hasNext());
assertPath(paths.next(), nodeA, nodeB, nodeC);
assertFalse("expected at most one path", paths.hasNext());
assertPath(algo.findSinglePath(nodeA, nodeC), nodeA, nodeB, nodeC);
}
@Test
public void canGetMultiplePathsInASmallRoadNetwork() throws Exception {
Node nodeA = graph.makeNode("A");
Node nodeB = graph.makeNode("B");
Node nodeC = graph.makeNode("C");
Node nodeD = graph.makeNode("D");
Node nodeE = graph.makeNode("E");
Node nodeF = graph.makeNode("F");
graph.makeEdge("A", "B", "length", 2d);
graph.makeEdge("A", "C", "length", 2.5d);
graph.makeEdge("C", "D", "length", 7.3d);
graph.makeEdge("B", "D", "length", 2.5d);
graph.makeEdge("D", "E", "length", 3d);
graph.makeEdge("C", "E", "length", 5d);
graph.makeEdge("E", "F", "length", 5d);
graph.makeEdge("C", "F", "length", 12d);
graph.makeEdge("A", "F", "length", 25d);
Dijkstra algo =
new Dijkstra(
PathExpanders.allTypesAndDirections(), CommonEvaluators.doubleCostEvaluator("length"));
// Try the search in both directions.
for (Node[] nodes : new Node[][] {{nodeA, nodeF}, {nodeF, nodeA}}) {
int found = 0;
Iterator<WeightedPath> paths = algo.findAllPaths(nodes[0], nodes[1]).iterator();
for (int i = 0; i < 2; i++) {
assertTrue("expected more paths", paths.hasNext());
Path path = paths.next();
if (path.length() != found && path.length() == 3) {
assertContains(path.nodes(), nodeA, nodeC, nodeE, nodeF);
} else if (path.length() != found && path.length() == 4) {
assertContains(path.nodes(), nodeA, nodeB, nodeD, nodeE, nodeF);
} else {
fail("unexpected path length: " + path.length());
}
found = path.length();
}
assertFalse("expected at most two paths", paths.hasNext());
}
}
private static Iterator<Node> findPath(Node s, Node e) {
Iterator<Node> it;
try (Transaction tx = graphDb.beginTx()) {
PathFinder<Path> finder =
GraphAlgoFactory.shortestPath(
PathExpanders.forTypeAndDirection(RelTypes.STD, Direction.OUTGOING), 15);
Iterable<Path> paths = finder.findAllPaths(s, e);
Path path = paths.iterator().next();
it = path.nodes().iterator();
if (it.hasNext()) {
System.out.println(it.next().getProperty("name"));
}
if (it.hasNext()) {
System.out.println(it.next().getProperty("name"));
}
if (it.hasNext()) {
System.out.println(it.next().getProperty("name"));
}
tx.success();
}
return it;
}
protected PathFinder<Path> instantiatePathFinder(int maxDepth) {
return allPaths(PathExpanders.allTypesAndDirections(), maxDepth);
}