Pimcore\Model\Asset::getId PHP Method

    public function getId()
    {
        return (int) $this->id;
    }

 /**
  * @param  Model\Asset $target
  * @param  Model\Asset $source
  * @return Model\Asset copied asset
  */
 public function copyRecursive($target, $source)
 {
     // avoid recursion
     if (!$this->_copyRecursiveIds) {
         $this->_copyRecursiveIds = [];
     }
     if (in_array($source->getId(), $this->_copyRecursiveIds)) {
         return;
     }
     $source->getProperties();
     $new = clone $source;
     $new->id = null;
     if ($new instanceof Asset\Folder) {
         $new->setChilds(null);
     }
     $new->setFilename(Element\Service::getSaveCopyName("asset", $new->getFilename(), $target));
     $new->setParentId($target->getId());
     $new->setUserOwner($this->_user->getId());
     $new->setUserModification($this->_user->getId());
     $new->setDao(null);
     $new->setLocked(false);
     $new->setCreationDate(time());
     $new->setStream($source->getStream());
     $new->save();
     // add to store
     $this->_copyRecursiveIds[] = $new->getId();
     foreach ($source->getChilds() as $child) {
         $this->copyRecursive($new, $child);
     }
     if ($target instanceof Asset\Folder) {
         $this->updateChilds($target, $new);
     }
     return $new;
 }