docs: public void doFilter(ActionRequest request, ActionResponse response, FilterChain chain) throws IOException,
              PortletException {
  
          // Lazily initialize the delegate if necessary.
          initDelegate(true);
  
          if (this.actionDelegate == null) {
              throw new IllegalStateException("The delegate PortletFilter does not implement ActionFilter but " + this.getFilterName() + " is configured with the ACTION_PHASE lifecycle.");
          }
  
          // Let the delegate perform the actual doFilter operation.
          invokeDelegate(this.actionDelegate, request, response, chain);
      }