The Viewlet Framework is InfoGrid's architecture for meta-data-driven, REST-ful user interfaces. Given an abstract MeshObject with a MeshObjectIdentifier, the Viewlet Framework renders this MeshObject for consumption by a typical browser using concrete formats such as HTML.
Generally, the Viewlet Framework constructs a user interface component based on a request (e.g. HTTP request) from the user for a particular MeshObject (identified by its MeshObjectIdentifier, such as the URL typed into the browser), and contextual information. Contextual information includes:
- a specific request from the user, by means of an appended URL parameter, for a particular kind of user interface (e.g. "please use a Property Sheet")
- the requested MIME type
- the user's Locale settings
- user-specific preferences
and the like.
The MeshObject itself can also be examined. For example, one type of rendering might be used for a MeshObject blessed with a Customer EntityType, while another would be used for a MeshObject blessed with an Order EntityType.