Base::collectResources

private function collectResources($resourceKeyList)
{
	$resources = [];
	$errors = $this->getResourceNameErrors($resourceKeyList);
	if (!$errors)
	{
		foreach ($resourceKeyList as $key)
		{
			switch ($key)
			{
				case 'carddav':
					$resources[] = new CardDav();
					break;
				case 'caldav':
					$resources[] = new CalDav();
					break;
				default:
					$resources[] = new CardDav();
					$resources[] = new CalDav();
			}
		}
	}
	else
	{
		$this->errors += $errors;
	}

	return $resources;
}