[udig-devel] Conflict of interest w/ SelectionModel

[Jody Garnett <jgarnett@xxxxxxxxxxxxxxx>]

Hi Jesse working on the SelectionView,

There is a bit of a disconnect between the existing model and what I was 
expecting.

I was expecting the the "data model" similar to that represented by 
Collection<java.util.Map.Entry<Layer,FeatureResults>> getFeatures().  
This is the model I would like to edit using the SelectionView and a 
Query builder.

Understandably this is not the model you want to work with when 
implementing selection tools, that model seems to be:
List<Selection> getSelections();

where:
interface Selection {
   public Filter getFilter(Layer layer);
}

The only implementation of which is FilterQuery( GeometryFilter ) - and 
is what the various selection tools create during the course of their 
opperation. This works quite nicly for undo redo support, but will 
interact poorly with the idea of Layers having a Selectable state, and 
so on.

The implementation of SelectionModelImpl.getFeatures is also suspect - 
for a given layer several Map.Entrys may exist, presumably these are 
implicitly bound together by client code with an OR?

I think what I will do is change Selection to be something like:
interface LayerSelection {
   Layer layer;
   Filter filter; // can use OR to produce a single fitler out of many
}

And to maintain something easy for Tool writers to call SelectionModel 
can have a select( Filter ) method, this will churn through the list of 
available Layers and only produce LayerSelections for those that are 
selectable.

Jody