Convert GraphResultSet JSON using Graphson

Question

I'm trying to convert the GraphResultSet object to JSON format similar to datastax studio returns. I'm trying to use Graphson. Is there any sample codes convert the result object to JSON?

i tried the following from the tikerpop blueprints but its not working

List<GraphNode> gf=((GraphResultSet) resultSet).all();
Vertex v = (Vertex) gf.get(0).asVertex();
                JSONObject json = null;
                try {
                    json = GraphSONUtility.jsonFromElement((Element) v,getElementPropertyKeys((Element) v, false), GraphSONMode.COMPACT);
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

I'm getting a GraphResultSet object from dse, It has vertex and edges. I wanted to output in JSON format.

How it not working? Does it gives exception, or it doesn't return anything? — Alex Ott, Jan 16 '18 at 09:53
It is throwing exception java.lang.ClassCastException: com.datastax.driver.dse.graph.DefaultVertex cannot be cast to com.tinkerpop.blueprints.Element — Sads, Jan 16 '18 at 13:33
Note that Blueprints is a TinkerPop 2.x project and not relevant to TinkerPop 3.x or DSE Graph. — stephen mallette, Jan 16 '18 at 15:24
I'm trying to get a proper JSON object out of GraphResultSet , is there a way to do that — Sads, Jan 16 '18 at 17:21
What you get right now looks more like toString... I need to look further into code — Alex Ott, Jan 16 '18 at 17:31
GraphResultSet resultSet = store.querywithParam(store.getConnectionTx(), 3, vertexTraversal); The result set contains Vertex and Edge Objects. I need JSON output of the resultSet Object. Is there an API to do it? — Sads, Jan 16 '18 at 18:44
I want a output similar to what we get RAW JSON in datastax studio — Sads, Jan 16 '18 at 18:48

score 2 · Answer 1 · answered Jan 19 '18 at 21:28

There is no direct way for now to convert a DSE driver graph object into JSON. However if using the DSE driver 1.5.0 you can configure the driver to use GraphSON1 if you are looking for simple JSON responses. Then simply output the String representation of GraphNode:

DseCluster dseCluster = DseCluster.builder().addContactPoint("127.0.0.1")
  .withGraphOptions(
    new GraphOptions()
      .setGraphName("demo")
      // GraphSON version is set here:
      .setGraphSubProtocol(GraphProtocol.GRAPHSON_1_0)
  )
  .build();

DseSession dseSession = dseCluster.connect();

// create query
GraphStatement graphStatement = [.....];

GraphResultSet resultSet = dseSession.executeGraph(graphStatement);
for (GraphNode gn : resultSet) {
    String json = gn.toString();
}

Thanks, I wrote a custom function, but this one helps & it works !! — Sads, Jan 21 '18 at 01:50

score 1 · Accepted Answer · answered Jan 16 '18 at 14:08

1

You can't directly cast between com.datastax.driver.dse.graph.DefaultVertex & com.tinkerpop.blueprints.Element.

There is GraphSONUtils class (src) in DSE Java driver that should be able to handle these conversions. But because it's in the "internal" package, I expect that changes may happen any time.

answered Jan 16 '18 at 14:08

Alex Ott

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I'm trying to get the JSON output of the resultset and the DSE driver conversions is not a proper JSON format. GraphSON utils convert it but it's not similar to the studio output – Sads Jan 16 '18 at 14:46
Can you add into post what you expect to get, and what you get - otherwise it's hard to say what's wrong... – Alex Ott Jan 16 '18 at 16:16
Added more details – Sads Jan 16 '18 at 17:19

Convert GraphResultSet JSON using Graphson

2 Answers2