code: public Response directInvoke(String request, int timeout, Map<String,String> meta_data)
              throws AdapterException, ConnectionException {
          init();
          if (logger == null)
              logger = LoggerUtil.getStandardLogger();
          Object connection = null;
          try {
              connection = openConnection();
              return doInvoke(connection, new Request(request), timeout, meta_data);
          } finally {
              if (connection != null)
                  closeConnection(connection);
          }
      }
docs: This method is used for directly invoke the adapter activity
  from code, rather than as part of process execution flow.