The Web Graph Database


Viewlet Framework

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.

The basic Viewlet Framework equally applies to web and rich client applications, although the current InfoGrid code base does not contain rich client components any more.

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.

The actual match-making between MeshObject, contextual information, and selected Viewlet is performed by a ViewletFactory, which can be freely defined by the application developer.

The Viewlet Framework requires the use of InfoGrid Html Templates to assemble the final output.

See also:

Last modified 4 years ago Last modified on 01/19/10 06:28:03