/**
* A reference accessor the static singleton instantiation of the adapter
* for the user agent, constructing the adapter with the user agent string
* if the adapter has not already been instantiated.
*
* @return User_Agent_Adapter_Interface
*/
public static function &adapter()
{
if (self::$_adapter === null) {
if (($ua = User_Agent::get()) !== false) {
require_once strtolower(Config::get('user_agent', 'adapter')) . '.class.php';
$adapter_class = Config::get('user_agent', 'adapter');
self::$_adapter = new $adapter_class($ua);
} else {
require_once 'user_agent_empty_adapter.class.php';
self::$_adapter = new User_Agent_Empty_Adapter();
}
}
return self::$_adapter;
}
