Updating the entire value of vertex property with List cardinality in Titan graph database

JavaExample.java

package pluradj.titan.tinkerpop3.example;

import static org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__.*;

import com.thinkaurelius.titan.core.Cardinality;
import com.thinkaurelius.titan.core.PropertyKey;
import com.thinkaurelius.titan.core.TitanFactory;
import com.thinkaurelius.titan.core.TitanGraph;
import com.thinkaurelius.titan.core.schema.TitanManagement;

import java.util.Arrays;
import java.util.ArrayList;
import java.util.List;

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.T;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// https://github.com/pluradj/titan-tp3-java-example
public class JavaExample {
    private static final Logger LOGGER =
            LoggerFactory.getLogger(JavaExample.class);

    private static final String POST_KEYWORD = "post_keyword";

    public static void updateProperties(final Vertex nextVertex) {
        final GraphTraversalSource g = nextVertex.graph().traversal();

        final List<String> keywords = Arrays.asList("three", "four", "five");
        if (keywords.size() > 0) {
            nextVertex.graph().traversal().V(nextVertex).properties(POST_KEYWORD).drop().iterate();
            LOGGER.info("dropped = "+ g.V(nextVertex).properties(POST_KEYWORD).count().next() + " " + g.V(nextVertex).values(POST_KEYWORD).toList());

            for (String keyword : keywords) {
                nextVertex.property(POST_KEYWORD, keyword);
            }
            LOGGER.info("added = "+ g.V(nextVertex).properties(POST_KEYWORD).count().next() + " " + g.V(nextVertex).values(POST_KEYWORD).toList());
        }
        nextVertex.graph().tx().commit();
    }

    public static void main(String[] args) {
        String dataDir = "./data";
        TitanGraph graph = TitanFactory.open("berkeleyje:" + dataDir);
        GraphTraversalSource g = graph.traversal();

        TitanManagement mgmt = graph.openManagement();
        PropertyKey name = mgmt.makePropertyKey(POST_KEYWORD).dataType(String.class).cardinality(Cardinality.LIST).make();
        mgmt.commit();

        final Vertex v = graph.addVertex(POST_KEYWORD, "one", POST_KEYWORD, "two");
        graph.tx().commit();
        LOGGER.info("start = "+ g.V(v).properties(POST_KEYWORD).count().next() + " " + g.V(v).values(POST_KEYWORD).toList());

        updateProperties(v);

        LOGGER.info("done = "+ g.V(v).properties(POST_KEYWORD).count().next() + " " + g.V(v).values(POST_KEYWORD).toList());

        System.exit(0);
    }
}

http://stackoverflow.com/questions/36540170/updating-the-entire-value-of-vertex-property-with-list-cardinality-in-titan-grap