code: @Override
      public final CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) {
          final CacheKeyBuilder<String, String> cacheKeyBuilder = CacheKey.builder(getName());
  
          final PreferencesScope stylesheetPreferencesScope =
                  this.getStylesheetPreferencesScope(request);
  
          this.stylesheetUserPreferencesService.populateStylesheetParameters(
                  request, stylesheetPreferencesScope, cacheKeyBuilder);
  
          this.stylesheetUserPreferencesService.populateOutputProperties(
                  request, stylesheetPreferencesScope, cacheKeyBuilder);
  
          return cacheKeyBuilder.build();
      }
docs: /* (non-Javadoc)
  @see org.apereo.portal.rendering.xslt.TransformerConfigurationSource#getTransformerConfigurationKey(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)