public static function condition($type = null)
	{
		$class = get_called_class();

		// a specific condition requested?
		if (property_exists($class, '_conditions'))
		{
			if ($type !== null)
			{
				return isset(static::$_conditions[$type]) ? static::$_conditions[$type] : array();
			}
			else
			{
				return static::$_conditions;
			}
		}
		else
		{
			return array();
		}
	}