public function getSiblings()
{
if ($this->siblings === null) {
$list = new Asset\Listing();
// string conversion because parentId could be 0
$list->addConditionParam("parentId = ?", (string) $this->getParentId());
$list->addConditionParam("id != ?", $this->getId());
$list->setOrderKey("filename");
$list->setOrder("asc");
$this->siblings = $list->load();
}
return $this->siblings;
}