Pimcore\Model\Document\Hardlink::setSourceId PHP Method

    public function setSourceId($sourceId)
    {
        $this->sourceId = (int) $sourceId;
        return $this;
    }

 protected function setValuesToDocument(Document\Hardlink $link)
 {
     // data
     $data = \Zend_Json::decode($this->getParam("data"));
     $sourceId = null;
     if ($sourceDocument = Document::getByPath($data["sourcePath"])) {
         $sourceId = $sourceDocument->getId();
     }
     $link->setSourceId($sourceId);
     $link->setValues($data);
     $this->addPropertiesToDocument($link);
 }