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gremlinjanusgraphgremlin-java

Gremlin query to traverse JanusGraph with step count until leaf vertex

I have a JanusGraph with vertices containing property key "ID" and edges labelled as "ML_EDGE", containing property key "STRENGTH".

I have to start from a vertex and traverse the graph based on the edges which has highest the "STRENGTH".

The following query works fine.

g.V().has('ID','id').repeat(outE("ML_EDGE").has("STRENGTH",gt(0)).limit(1).inV()).times(3);

But I have to stop traversal when a leaf vertex in encountered. So I made some changes.

g.V().has('ID','id').repeat(outE("ML_EDGE").has("STRENGTH",gt(0)).limit(1).inV()).until(or(loops().is(eq(2)),outE().count().is(eq(0))))

This query returns empty result.

Also, with the first query, I tried replacing times() with until() and got the query, g.V().has('ID','id').repeat(outE("ML_EDGE").has("STRENGTH",gt(0)).limit(1).inV()).until(loops().is(eq(1)));

It doesn't work either.

I am a newbie to JanusGraph and I am stuck. Any help to fix this would be life-saving.

Solution 
  • g.V().has('ID', 'id').repeat(optional(outE('ML_EDGE').has('STRENGTH', gt(0)).limit(1).inV())).times(10)

    Use of optional() in repeat() solved the issue.

    Hope this would solve the problem.