Node Traversal to Java String Set?

Question

So I am having trouble how I would convert a nodeTraversal into Hashset.

GraphTraversal<vertex, vertex>nodeTraversal = this.central.V().has(nodeid).in("node").values(nodeId);

So far I have: GraphTraverl<vertex, vertex>nodeTraversal that returns the values of ids. I want to then convert that to a set by doing .toSet(), but get a cannot convert set<Object> to set<String>. I try to add a .join(',') like the tinkerpop docs but not luck.

Anyone know why?

Answer 1

I assume this is just an issue with getting the generics right. You've created nodeTraversal with <Vertex, Vertex> but that's technically not what you're returning. the outgoing object from nodeTraversal (i.e. the second Vertex generic definition) is not a Vertex but the data type of whatever the property given to values() is. Let's assume it was a String. Your code would look like:

GraphTraversal<Vertex, String> nodeTraversal = g.V().has("x").in("node").values("y");
Set<String> ids = nodeTraversal.toSet();