docs: public static void setCachingHeaders(
              int maxAge,
              boolean publicScope,
              long lastModified,
              PortletResourceOutputHandler portletResourceOutputHandler) {
          if (maxAge != 0) {
              portletResourceOutputHandler.setDateHeader("Last-Modified", lastModified);
  
              if (publicScope) {
                  portletResourceOutputHandler.setHeader("CacheControl", "public");
              } else {
                  portletResourceOutputHandler.setHeader("CacheControl", "private");
              }
  
              if (maxAge < 0) {
                  // If caching "forever" set expires and max-age to 1 year
                  maxAge = YEAR_OF_SECONDS;
              }
  
              portletResourceOutputHandler.setDateHeader(
                      "Expires", System.currentTimeMillis() + TimeUnit.SECONDS.toMillis(maxAge));
              portletResourceOutputHandler.addHeader("CacheControl", "max-age=" + maxAge);
          }
      }