[OpenLayers-Dev] Rule subclasses and 2.6

[Tim Schaub]

Hey-

I know this won't concern too many people, but I thought I'd ask for 
opinions anyway.

The new style work includes the addition of OpenLayers.Rule and 
subclasses.  The base Rule class corresponds well to the sld:Rule 
element in the SLD spec (min/max limits constraints, symbolizers, etc.).

The subclasses of Rule (Comparison, FeatureId, and Logical) correspond 
well to ogc:Filter elements in the Filter Encoding specification. 
Though our Rule subclasses can have a symbolizer, an ogc:Filter knows 
nothing of a symbolizer - in SLD, an ogc:Filter element is a child of an 
sld:Rule that has a symbolizer.

Filters are useful for more than just SLD.  If we ever want to support 
filters in WFS, it would be useful to use the code currently in the Rule 
subclasses (minus the symbolizer and min/max scale limits).  There is 
code in the SLD format for reading and writing ogc:Filter elements that 
could be pulled out in to a Filter format class.

Since 2.6 is upon us, there are two scenarios that make sense to me:

1) Do no mark Rule subclasses as part of the API.  Later, change them so 
they are Filter subclasses and require that they be added to a Rule 
(with a symbolizer) for things like styling.  They could also be used 
alone (without rules) for things like WFS.  This would also require 
changing the georss-flickr.html example (that uses Rule.Comparison) and 
the wiki page on styling.

2) Add Filter classes later and keep (the redundant) Rule subclasses 
around until 3.0.


Any ideas?

Tim