AllJoyn™ Notification Framework API Guide
Provide correct values when sending a notification
The Notification object that will be sent using the Notification service framework allows for multiple values to be entered. Specifically, the notification text can be provided in various languages and string lengths.
Well-formed text string
It is very important that this string be a complete and correct message that will be displayed on any Notification Consumer application. The notification will support multiple languages so that the correct language of the platform can be used; this avoids translating strings to be displayed. As such, it is important for the manufacturer of the software running on the Notification Producer side to send the correct translations for the languages that are supported.
Machine-to-machine use case
The notification text entries should never be used for any other purpose than providing a human-readable message. A notification message, by design, will be received and shown by any application to convey a meaning relevant to the sending device.
An application making use of the Notification service framework should never assume that a specific application designed to be the Notification Consumer side is the only instance in the proximal network. Again, every message will travel to all Notification Consumer applications to be displayed.
When to send an Emergency notification
A notification supports the following message types:
Use the Emergency message type only when something very important must be relayed to the consumer. For example, a notification about a social media-related update should have a message type of Information, while a notification about an appliance malfunction or a security system being triggered warrants the message type of Emergency.
Since a notification trigger uses UDP multicast, resulting in unreliable delivery, an Emergency notification should send multiple times, possibly until it can be verified that a user has received it and taken action.
NOTE: Use common sense when setting the message type. Consumers should not receive numerous messages other than those specified as an emergency notification. This is to avoid a person seeing a message like "The sky is blue" 8 times when it does not require an immediate action or response.
What is the purpose of rich notification media?
Besides the text payload, a notification can contain an icon and audio data. A television or other device with audio output capabilities can leverage the Notification service framework as a consumer. Audio content can contain a text-to-speech version of the notification message text, thereby allowing the end user to both view and hear the notification contents. Another use case involves a consumer that does not have visual display capabilities, such as a wireless speaker. In that case, a notification can be audibly conveyed to the user. An icon can be used to show some aspect of the notification, such as the producer it was sent from, or the content it contains. As an example, consider a coffee maker that sends a notification when it is done brewing. An icon can be used to represent the type of coffee that was selected, such as regular, strong, or decaf.
NOTE: The icon and audio data are not contained within the actual notification. Instead, an AllJoyn™ object path is used to obtain the icon or audio content that is sent as part of the notification. See the Notification API Guide listed at the top of this page for the platform you are targeting for details on using this capability.
How to use the TTL on a producer
The time to live (TTL) of a notification message defines the validity period of the message. A notification message can be received by a consumer that connects to the same network as the producer that sent the message during the defined TTL period. See the Notification Interface Definition for more information on this behavior and timelines of specific use cases.
As a general rule, the TTL for a notification should be set to correspond with the type of information included in the notification. For example, if the notification contains information that is no longer valid or useful after 5 minutes, the TTL should be set to 5 minutes.
NOTE: The TTL is not sent as part of the actual notification payload, and is instead used by the Notification service internally
How long to show the notification
The length of time to show a notification should be consistent with the following criteria:
- Behavior of the platform/application the notification is being displayed on
- Message type (Information, Warning, Emergency)
- Any preferences the user has set to view notifications.
For example, on an Android platform application, an Information notification can be shown with a short Toast (overlay message that is temporarily displayed), while a Warning notification can be shown with a long Toast. Additionally, the display of notifications can be integrated into the existing Android Notification system to provide for a consistent user experience. Refer to the NotificationServiceUISample application for example code.
How to handle a notification with response
A notification includes an optional field where the path of
a Control Panel can be specified (the response object path.)
This feature is used with notifications where a response,
such as a yes or no confirmation,is associated with the notification
and used to interact with the producer that sent the notification.
From a UI standpoint, the notification should include a button whose
onclick action will bring up a new view with the rendered Control Panel.
For example, the user can receive a notification from a smart coffee maker that has been on for an hour and not used. The notification can include text that gives the user the option to turn off the coffee maker, and response options of yes or no are presented to the user accompanying the notification text. Clicking on "yes" would invoke a method to render a view of the Control Panel at the response object path with the option of turning off the coffee machine; "no" would dismiss the notification.
Handling first time notification from a new appliance
By definition, a notification is sent to all Consumer applications connected to a network. Because the Consumer application is running on a TV or other device that a user is constantly viewing, it is important to filter the notifications on the appliance/device (consumer).
It is recommended that when the first notification is received by a consumer from an appliance/device, a UI is presented to the user prompting the user to configure the consumer application:
- How to receive notifications
- What priority of notifications should be shown
The UI should follow the example that is shown in the sample applications contained with the Notification service framework.