JanusGraph vertex.edges() returns a RelationConstructor rather an Iterator

Question

I'm trying basic JanusGraph operations on JVM.

When I attempt to simply create an edge between two vertices and calling vertex1.edges() I'm getting a result of org.janusgraph.graphdb.transaction.RelationConstructor rather Iterator<Edge>, which is against api.

I could regenerate the same result on Gremlin console once as shown below. But I'm getting proper org.janusgraph.graphdb.query.ResultSetIterator in my subsequent attempts.

gremlin> person = graph.addVertex(label, 'person')
==>v[163844144]
gremlin> graph.tx().commit()
==>null
gremlin> person2 = graph.addVertex(label, 'anotherperson')
==>v[245764240]
gremlin> person.addEdge("knows", person2);
==>e[2pjoxy-2pjqy8-29ed-42bkwg][163844144-knows->245764240]
gremlin> graph.tx().commit()
==>null
gremlin> person.class
==>class org.janusgraph.graphdb.vertices.StandardVertex
gremlin> mye = person.edges(Direction.BOTH, "knows")
==>e[2pjoxy-2pjqy8-29ed-42bkwg][163844144-knows->245764240]
gremlin> mye.class
==>class org.janusgraph.graphdb.transaction.RelationConstructor$1$1

Could someone please explain why and/or suggest a workaround? Thank you!

Answer 1

You are getting back class org.janusgraph.graphdb.transaction.RelationConstructor$1$1. Take notice of the $1$1 which is indicating that you are dealing with an anonymous class within RelationConstructor. In particular, you are getting back this Iterator from the method readRelation(). To be sure, you could have called mye instanceof Iterator in your session to verify.

In this example below, I've added null to the end of the mye assignment to prevent the Gremlin Console auto-iteration behavior.

gremlin> mye = person.edges(Direction.BOTH, "knows"); null
==>null
gremlin> mye instanceof Iterator
==>true
gremlin> myedge = (mye.hasNext()) ? mye.next() : null
==>e[2pjoxy-2pjqy8-29ed-42bkwg][163844144-knows->245764240]
gremlin> myedge.class
==>class org.janusgraph.graphdb.relations.CacheEdge