/**
* Get a handle for this object
*
* This function returns an unique identifier for the object. This id can be used as a hash key for storing objects
* or for identifying an object
*
* @return string A string that is unique
*/
public function getHandle()
{
if (isset($this->_identity_key)) {
$handle = $this->getProperty($this->_identity_key);
} else {
$handle = parent::getHandle();
}
return $handle;
}
