code: public final TagRepository getTagRepository() {
  
          if (tagRepository == null && rootTag != null) {
              synchronized (this) {
                  if (tagRepository == null) {
                      tagRepository = new TagRepository(ACCESS_OBJECT, this,
                              tagByWffId, rootTag);
                  }
              }
          }
  
          return tagRepository;
      }
docs: Gets the TagRepository to do different tag operations. This tag
  repository is specific to this BrowserPage instance.
  
  @return the TagRepository object to do different tag operations. Or null
  if any one of the BrowserPage#toString or
  BrowserPage#toOutputStream methods is not called.
  @since 2.1.8
  @author WFF