如何以tinkerpop / gremlin格式而不是DSE图格式返回Vertex？ [英] How to return a Vertex in the tinkerpop/gremlin format instead of the DSE graph format?

问题描述

我正在尝试返回它刚刚用Gremlin创建的Vertex（以tinkerpop格式）：

I am trying to return a Vertex (in tinkerpop format) that it was just created with Gremlin:

DseCluster dseCluster = DseCluster.builder()
        .addContactPoint(DbC.dseHost)
        .build();
DseSession dseSession = dseCluster.connect();
GraphTraversal traversal = graph.addV(VertexLabels.User)
        .property("username", "testuser")
GraphStatement graphStatement = DseGraph.statementFromTraversal(
    traversal
);
GraphResultSet grs = dseSession.executeGraph(graphStatement.setGraphName(DbC.graphName));
Vertex v = grs.one().as(Vertex.class);

我得到了这个例外......

and I am getting this exception...

java.lang.ClassCastException：com.datastax.driver.dse.graph.DefaultVertex无法强制转换为org.apache.tinkerpop.gremlin.structure.Vertex

如何更改代码以便以gremlin.structure.Vertex格式而不是DSE Graph Vertex格式返回？

How could the code be changed so that it returns in gremlin.structure.Vertex format instead of the DSE Graph Vertex format?

我正在使用：

<dependency>
    <groupId>com.datastax.cassandra</groupId>
    <artifactId>dse-driver</artifactId>
    <version>1.1.1-beta1</version>
</dependency>
<dependency>
    <groupId>com.datastax.cassandra</groupId>
    <artifactId>java-dse-graph</artifactId>
    <version>1.0.0-beta1</version>
</dependency>

我希望可以这样做，否则从TitanDB迁移会很痛苦..

I hope this can be done otherwise migration from TitanDB will be painful..

推荐答案

根据我与Datastax团队通过 jira 和电子邮件：

According to the lengthy discussion I had with Datastax Team through jira and emails:

确实可以使用Fluent API并获得纯Gremlin / tinkerpop对象。这可以如此处所示（ java -dse graph 1.x文档）直接在GraphTraversalSource上使用next（），toList（）而不使用将返回DSE对象的executeGraph（）。

It is indeed possible to have Fluent API and get back pure Gremlin/tinkerpop objects. This is possible as illustrated here (java-dse graph 1.x documentation) using next(), toList() directly on GraphTraversalSource and not using executeGraph() which will return the DSE Objects.

所以上面的代码更改为：

So the above code changes to:

Vertex user = graph.addV("User")
                 .property("username", "testuser").next();

其中 graph 是 GraphTraversalSource< Vertex，Vertex> object和 Vertex 是一个 org.apache.tinkerpop.gremlin.structure.Vertex object。

where graph is a GraphTraversalSource<Vertex,Vertex> object and Vertex is a org.apache.tinkerpop.gremlin.structure.Vertex object.

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