String attribName = type.getDescriptor(0).getLocalName();
SimpleFeatureCollection fc = DataUtilities.collection(roadFeatures);
SimpleFeatureSource fs = DataUtilities.source(fc);
try {
expr = ff.multiply(ff.property(attribName), ff.property(attribName));
expr2 = ff.add(expr, ff.literal(3));
} catch (IllegalFilterException e) {
fail(e.getMessage());
}