code: private void preEncode(FacesContext context) {
          setDataModel(null); // re-evaluate even with server-side state saving
          if (!keepSaved(context)) {
              ////noinspection CollectionWithoutInitialCapacity
              //saved = new HashMap<String, SavedState>();
              getStateHelper().remove(PropertyKeys.saved);
          }
      }
docs: (ie. encodeBegin()) or during a tree visit (ie. visitTree()).