The filter that will return all the features that need to be rendered throws: Exception - In case something goes wrong, IOException, IllegalTransformException etc...
Returns the query that selects all the features that need to be rendered for the layer.
the query that selects all the features that need to be rendered for the layer.
If not layer is not a CompositeRenderer then this is just a call to ILayer.isVisible().
Otherwise if one of the layers is visible then it should return true