public function getDevice($device_id)
{
if (empty($this->_devices[$device_id])) {
$device = new Application_Model_Device();
$device->find(array("app_id" => $this->getId(), "type_id" => $device_id));
if (!$device->getId()) {
$device->loadDefault($device_id);
$device->setAppId($this->getId());
}
$this->_devices[$device_id] = $device;
}
return $this->_devices[$device_id];
}