Meeting Summary - 4 Feb 2008
[Meeting Summary - 4 Feb 2008] The DDR API: Simple and Advanced.
The participants were given a summary of the results of the DDR API editors’ meeting that took place last week. The primary outcome was a simplified API that forgoes the support for Aspect, a mechanism that enables properties to distinguish how they are applied to different parts of the delivery context. The Simple API also masks the use of the Context Key, by only having query methods that take direct context evidence as input, and giving values for vocabulary terms as output. An early version of the Simple API in Java has been placed into the public domain. There was some disappointment that the Simple API would not incorporate many of the more complex features the group has been working on for the past year, and that there was a danger that the Simple API would not advance much beyond existing technologies. It was also noted that the more complex features could be captured in a new Working Group Note, to become the foundation of a successor Advanced API.
It was also noted that the Advanced API could eventually evolve to support access to any part of the delivery context, not just knowledge available beforehand in a repository. Furthermore, the applicability of such an API would extend to any modality of the Web, not just mobile devices. In time, the Advanced API would exceed the scope of the DDWG’s charter, so while it is valuable to the goals of the DDWG and the MWI, it should properly be transferred in time to a group within the W3C that has a greater mandate.
Some new proposals were discussed, mainly to suggest that the group focus on the Simple API while developing and capturing the remaining features for a future Advanced API. The absence of Aspect in the Simple API presents a problem with the Vendor, Model and Version terms in the latest draft of the Core Vocabulary. These terms can only be properly interpreted when given an Aspect (such as Hardware, Screen, Browser) in order to remove the ambiguities. Possible solutions include creating alternative terms in the vocabulary, so that the terms specify Aspects (e.g. BrowserVendor and PlatformVendor). Alternatively, terms that require Aspects could be removed from the vocabulary. Neither approach attracted much support, so an alternative was proposed: to consider a simple means of supporting Aspect in the Simple API.
Having discussed the pros and cons of the Simple and Advanced APIs, the use or absence of Aspects, and the desire to make progress within charter and in good time, the group came to the following majority conclusion: Split the API into Simple and Advanced. The Simple API provides a foundation for the development of adaptive content to be completed within the current charter. The Simple API is to be based on work resulting from the Editors Meeting with possible elaboration for example to introduce "Aspects". The Advanced API is moving towards a general interface for accessing delivery context information, not just a priori device knowledge and to complete it properly would be out of scope for DDWG. The group will continue work on the Advanced API with a view to capturing what has been learned, and developing the work to the point where it can be handed over to a group with broader scope.
Remaining issues regarding the vocabulary, some methods of the Simple API and conformance requirements were deferred to be discussed via the mailing list.
Attendees: Matt, Bryan, Rotan, Martin, Jo, Anders, Rafa, José, Abel, Rodrigo, Nacho