code: public void schedule(CmsValidationController action) {
  
          if (m_idle) {
              m_idle = false;
              action.internalStartValidation();
          } else {
              m_actions.add(action);
          }
      }
docs: This schedules a new validation to be run after all currently scheduled or running validations have finished.<p>
  
  If there are no validations running, the validation will be started immediately.<p>
  
  @param action the validation to be scheduled