/**
* Returns an identifier object.
*
* Accepts various types of parameters and returns a valid identifier. Parameters can either be an
* object that implements ObjectInterface, or a ObjectIdentifier object, or valid identifier
* string. Function recursively resolves identifier aliases and returns the aliased identifier.
*
* If the identifier does not have a type set and it's not an alias the type will default to 'lib'.
* Eg, event.publisher is the same as lib:event.publisher.
*
* If no identifier is passed the object identifier of this object will be returned.
*
* @param mixed $identifier An ObjectIdentifier, identifier string or object implementing ObjectInterface
* @return ObjectIdentifier
* @throws ObjectExceptionInvalidIdentifier If the identifier is not valid
*/
public function getIdentifier($identifier = null)
{
//Get the identifier
if (isset($identifier)) {
if (!$identifier instanceof ObjectIdentifierInterface) {
if ($identifier instanceof ObjectInterface) {
$identifier = $identifier->getIdentifier();
} else {
$identifier = new ObjectIdentifier($identifier);
}
}
//Get the identifier object
if (!($result = $this->__registry->find($identifier))) {
$result = $this->__registry->set($identifier);
}
} else {
$result = $this->__object_identifier;
}
return $result;
}
