DataStore.getView(Query) returns a SimpleFeatureSource. The javadocs are a bit vague on the purpose of this method. It doesn't seem to be used in GeoTools or GeoServer (aaime) although Jody says he makes some use of it in uDig to get read-only views.
Suggest that it be dropped or deprecated in 2.7 (the patch removes it) and replaced by a DataUtilities method.
This is an API change so there's a proposal for it at http://docs.codehaus.org/display/GEOTOOLS/Remove+DataStore+getView+method