config-prettyfaces/src/main/java/com/ocpsoft/pretty/faces/util/FacesStateUtils.java
public static boolean isPostback(final FacesContext context)
   {
      RenderKitFactory factory = (RenderKitFactory) FactoryFinder.getFactory(FactoryFinder.RENDER_KIT_FACTORY);
      RenderKit renderKit = factory.getRenderKit(context, RenderKitFactory.HTML_BASIC_RENDER_KIT);
      return renderKit.getResponseStateManager().isPostback(context);
   }
public static boolean isPostback(final FacesContext context)
   {
      RenderKitFactory factory = (RenderKitFactory) FactoryFinder.getFactory(FactoryFinder.RENDER_KIT_FACTORY);
      RenderKit renderKit = factory.getRenderKit(context, RenderKitFactory.HTML_BASIC_RENDER_KIT);
      return renderKit.getResponseStateManager().isPostback(context);
   }
Determine if the current request/FacesContext is in PostBack state