在janusgraph图模型中每个非默认vertex label都是对应一个vertex吗？

[Windyhe]

以下代码节选自StandardJanusGraphTx.java (janusgraph-core-0.5.1.jar)，从代码最后几行来看，当新增一个vertex时，如果该vertex使用的不是默认label，那么就会新建一个边，使该vertex指向 label vertex，是这样吗？

如果是这样，当用gremlin查询某个vertex的出边和入边时，却并没有将该边（vertex->label vertex）显示出来，所以这是在gremlin里面做了过滤处理吗？尽管如此，其存储后端（比如HBASE）还是有将 label vertex 存为一条rowkey的吧？

    public JanusGraphVertex addVertex(Long vertexId, VertexLabel label) {
        this.verifyWriteAccess();
        if (label == null) {
            label = BaseVertexLabel.DEFAULT_VERTEXLABEL;
        }

        if (vertexId != null && !this.graph.getConfiguration().allowVertexIdSetting()) {
            log.info("Provided vertex id [{}] is ignored because vertex id setting is not enabled", vertexId);
            vertexId = null;
        }

        Preconditions.checkArgument(vertexId != null || !this.graph.getConfiguration().allowVertexIdSetting(), "Must provide vertex id");
        Preconditions.checkArgument(vertexId == null || VertexIDType.NormalVertex.is(vertexId), "Not a valid vertex id: %s", new Object[]{vertexId});
        Preconditions.checkArgument(vertexId == null || ((InternalVertexLabel)label).hasDefaultConfiguration(), "Cannot only use default vertex labels: %s", new Object[]{label});
        Preconditions.checkArgument(vertexId == null || !this.config.hasVerifyExternalVertexExistence() || !this.containsVertex(vertexId), "Vertex with given id already exists: %s", new Object[]{vertexId});
        StandardVertex vertex = new StandardVertex(this, IDManager.getTemporaryVertexID(VertexIDType.NormalVertex, this.temporaryIds.nextID()), (byte)1);
        if (vertexId != null) {
            vertex.setId(vertexId);
        } else if (this.config.hasAssignIDsImmediately() || ((VertexLabel)label).isPartitioned()) {
            this.graph.assignID(vertex, (VertexLabel)label);
        }

        this.addProperty(vertex, BaseKey.VertexExists, Boolean.TRUE);
        if (label != BaseVertexLabel.DEFAULT_VERTEXLABEL) {
            Preconditions.checkArgument(label instanceof VertexLabelVertex);
            this.addEdge(vertex, (JanusGraphVertex)label, BaseLabel.VertexLabelEdge);
        }

        this.vertexCache.add(vertex, vertex.longId());
        return vertex;
    }