code: public static String getVersionString(CmsHistoryResourceBean bean) {
  
          if (bean.getVersion().getVersionNumber() != null) {
              return bean.getVersion().getVersionNumber().toString();
          } else if (bean.getVersion().isOffline()) {
              return "0";
          } else {
              return "-1";
          }
      }
docs: Builds a version string which can be used by CmsResourceComparison from a history resource bean.<p>
  
  This is not really a user-readable string, it is meant for internal usage.
  
  @param bean the history resource bean
  @return the version string