public function __construct(Cascade $cascade)
 {
     $this->cascade = $cascade;
     $this->clearResults();
     $this->cache = u\Cache::getInstance($cascade->getService());
     $this->cache->clearCache();
 }
 public function __construct(Cascade $source_cascade, Cascade $target_cascade)
 {
     try {
         $this->source_cascade = $source_cascade;
         $this->target_cascade = $target_cascade;
         $this->source_service = $source_cascade->getService();
         $this->target_service = $target_cascade->getService();
         $this->source_url = $this->source_service->getUrl();
         $this->target_url = $this->target_service->getUrl();
         $this->source_site_set = false;
         $this->target_site_set = false;
         $this->cache = array();
         // instance->site->path->id
     } catch (\Exception $e) {
         echo S_PRE . $e . E_PRE;
     }
 }