protected function save()
 {
     if ($this->is_apc_available()) {
         if ($this->form->get_value('enable_apc')) {
             DataStoreFactory::set_apc_enabled(true);
         } else {
             DataStoreFactory::set_apc_enabled(false);
         }
     }
     if ($this->form->get_value('enable_css_cache')) {
         $this->css_cache_config->enable();
     } else {
         $this->css_cache_config->disable();
     }
     if (!$this->form->field_is_disabled('level_css_cache')) {
         $this->css_cache_config->set_optimization_level($this->form->get_value('level_css_cache')->get_raw_value());
     }
     CSSCacheConfig::save();
     AppContext::get_cache_service()->clear_css_cache();
 }