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.

Received on Thursday, 7 February 2008 12:20:40 UTC