private void writeVertices(JsonWriter writer, Set<Vertex> vertices) throws IOException {
    writer.name("vertices");
    writer.beginArray();
    for (Vertex vertex: vertices) {
      writer.beginObject();
      writer.name("id").value(vertex.id);
      writer.name("vertexType").value(vertex.type.name());
      writer.name("vertexId").value(vertex.label);
      writer.endObject();
    }
    writer.endArray();
  }
Write out an JSON array of vertices.
ql/src/java/org/apache/hadoop/hive/ql/hooks/LineageLogger.java