A Document-based Framework for Internet Application Control
This paper motivates and details a document-based framework for manipulating the components that comprise distributed Internet applications. In the framework, XML documents are used to describe both server-side functionality and the mapping between a client's applications and the servers it accesses. Our system model contrasts with explicitly context-aware application designs, where location information must be explicitly manipulated by the application to affect change; instead, a middleware layer is interposed between client applications and services so that invocations between the two can be transparently remapped. This approach is useful for a subset of application domains, including our example domain of ``remote control'' of local resources (e.g., lights, stereo components, etc.). We illustrate how the framework allows for 1) remapping of a portion of an existing user interface to a new service, 2) viewing of arbitrary subsets and combinations of the available functionality, and 3) mixing dynamically-generated user interfaces with existing user interfaces.
The use of a document-based framework in addition to a conventional object-oriented programming language provides a number of key features. One of the most useful is that it exposes the mappings between programs/UIs and the objects to which they refer, thereby providing a standard location for manipulation of this indirection.