/**
* Return the length of a given list or set.
*
* @param string $key
* @param string $type
* @return integer|\UnexpectedValueException
*/
public function length($key, $type = null)
{
if (is_null($type)) {
$type = $this->type($key);
}
switch ($type) {
case 'list':
return $this->database->llen($key);
case 'zset':
return $this->database->zcard($key);
default:
throw new UnexpectedValueException("List type '{$type}' not supported.");
}
}