public function parse()
 {
     if ($this->getProtocol() === 'RSS') {
         // channel
         $parser = new Parser($this->xml->channel, $this, 'channel');
         $channel = $parser->getData();
         $channel->protocol = strtolower($this->getProtocol());
         $this->setData($channel);
         // items
         $this->items = new XMLObjectsCollection($this->xml->channel);
         foreach ($this->items as $i => $item) {
             $parser = new Parser($item, $this, 'item');
             $item = $parser->getData();
             $item->protocol = strtolower($this->getProtocol());
             $item->id = $this->id . '_' . Helper::encodeStringToId($item->title->content);
             $this->items->addData($i, $item);
         }
     } elseif ($this->getProtocol() === 'ATOM') {
         // entry
         $parser = new Parser($this->xml, $this, 'feed');
         $channel = $parser->getData();
         $channel->protocol = strtolower($this->getProtocol());
         $this->setData($channel);
         // entry
         $this->items = new XMLObjectsCollection($this->xml);
         foreach ($this->items as $i => $item) {
             $parser = new Parser($item, $this, 'feed');
             $item = $parser->getData();
             $item->protocol = strtolower($this->getProtocol());
             $item->id = $this->id . '_' . Helper::encodeStringToId($item->title->content);
             $this->items->addData($i, $item);
         }
     }
 }