/**
* @param string $key
* @return null
*/
public function setKey($key)
{
if (!isset($this->loadedFields['key'])) {
$this->loadProperties();
}
$oldValue = null;
if (array_key_exists('key', $this->loadedValues)) {
$oldValue = $this->loadedValues['key'];
}
if ($oldValue === $key) {
$this->key = $key;
return;
}
return parent::setKey($key);
}
