code: public static final long toVertexId(long id) {
          Preconditions.checkArgument(id > 0, "Vertex id must be positive: %s", id);
          Preconditions.checkArgument(IDManager.VertexIDType.NormalVertex.removePadding(Long.MAX_VALUE) >= id, "Vertex id is too large: %s", id);
          return IDManager.VertexIDType.NormalVertex.addPadding(id);
      }
docs: Converts a user provided long id into a Titan vertex id. The id must be positive and can be at most 61 bits long.
  This method is useful when providing ids during vertex creation via {@link com.tinkerpop.gremlin.structure.Graph#addVertex(Object)}.
  
  @param id long id
  @return a corresponding Titan vertex id