/**
* Constructor.
*
* @param array $params Parameters:
* - collection: (string) The collection name.
* - mongo_db: [REQUIRED] (Horde_Mongo_Client) A MongoDB client object.
*/
public function __construct(array $params = array())
{
if (!isset($params['mongo_db'])) {
throw new InvalidArgumentException('Missing mongo_db parameter.');
}
parent::__construct(array_merge(array('collection' => 'horde_cache'), $params));
$this->_db = $this->_params['mongo_db']->selectCollection(null, $this->_params['collection']);
}