Order by path length in Java - titan

Question

I've got something like following graph:
g = new TinkerGraph()
v1 = g.addVertex([name: 'one'])
v2 = g.addVertex([name: 'two'])
v3 = g.addVertex([name: 'three'])
v4 = g.addVertex([name: 'four'])
v5 = g.addVertex([name: 'five'])
v1.addEdge('contains', v2)
v2.addEdge('contains', v3)
v3.addEdge('contains', v4)
v4.addEdge('contains', v5)
Now I want to remove v1 and all its "children"
v1.out('contains').loop(1){it.loops < 10}{true}.order{-it.a.path.toList().unique{a, b -> a <=> b}.size <=> it.b.path.toList().unique{a, b -> a <=> b}.size}.remove()
v1.remove()
(it must me removed from leaves)
Could you help me with rewriting this Groovy query to Java? We have a problem with the order{...} part. Not sure how to get the path from Pair<Vertex, Vertex>.

Answer 1

Not sure if order is important if you just need to remove a parent node and all of it's children. I wrote a junit test that I think solves your problem.
import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Graph;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.blueprints.impls.tg.TinkerGraph;
import org.junit.Assert;
import org.junit.Test;
import java.util.Iterator;
public class SOTest {
private static final String EDGE_LABEL = "contains";
#Test
public void testSomething(){
Graph g = new TinkerGraph();
Vertex v1 = createVertex(g, "name", "one");
Vertex v2 = createVertex(g, "name", "two");
Vertex v3 = createVertex(g, "name", "three");
Vertex v4 = createVertex(g, "name", "four");
Vertex v5 = createVertex(g, "name", "five");
v1.addEdge(EDGE_LABEL, v2);
v2.addEdge(EDGE_LABEL, v3);
v3.addEdge(EDGE_LABEL, v4);
v4.addEdge(EDGE_LABEL, v5);
removeParentAndChildren(v1);
Assert.assertEquals(g.getVertices().iterator().hasNext(), false);
}
private static void removeParentAndChildren(Vertex vertex) {
final Iterator<Vertex> vertexIterator = vertex.getVertices(Direction.OUT, EDGE_LABEL).iterator();
if(vertexIterator.hasNext()) {
vertex.getVertices(Direction.OUT, EDGE_LABEL).forEach(SOTest::removeParentAndChildren);
}
vertex.remove();
}
private Vertex createVertex(final Graph g, final String key, final String value) {
Vertex v = g.addVertex(null);
v.setProperty(key, value);
return v;
}
}

Answer 2

we end up using this:
new HawkularPipeline<>(v1)
.as("start")
.out(contains)
.loop("start", (x) -> true, (x) -> true)
.toList()
.forEach {
c -> c.remove();
}