code: protected String getUrl() {
          String shortUrl = null;
          if (branchReferral_ != null) {
              ServerRequestCreateUrl req = new ServerRequestCreateUrl(context_, alias_, type_, duration_, tags_,
                      channel_, feature_, stage_, campaign_,
                      BranchUtil.formatLinkParam(params_), null, false, defaultToLongUrl_);
              shortUrl = branchReferral_.generateShortLinkInternal(req);
          }
          return shortUrl;
      }
docs: /------------------------- Link Build methods---------------------------///