public function __construct($id = null, $sourceId = null)
 {
     if ($id && $id instanceof ContentReader) {
         $this->reader = $id;
         $id = $this->reader->getId();
     }
     $this->sourceIdentifier = $sourceId;
     $this->id = $id;
 }
 public function isReadable()
 {
     if (!parent::isReadable()) {
         return;
     }
     return strlen($this->getURL());
 }
 public function isReadable()
 {
     if (!parent::isReadable()) {
         return;
     }
     $info = $this->getInfo();
     return strlen($info) > 0;
 }