code: public static JsonLocation expectObjectStart(JsonParser parser)
          throws IOException, JsonReadException
      {
          if (parser.getCurrentToken() != JsonToken.START_OBJECT) {
              throw new JsonReadException("expecting the start of an object (\"{\")", parser.getTokenLocation());
          }
          JsonLocation loc = parser.getTokenLocation();
          nextToken(parser);
          return loc;
      }
docs: Delimiter checking helpers.