if (rd==null) {
throw new IOException(typeName + " is not a supported type");
}
// do we have such attribute?
final PropertyName property = rd.translateProperty(attributeName);
AttributeDescriptor ad = (AttributeDescriptor) property.evaluate(rd.getFeatureType());
if(ad == null) {
return new CloseableIteratorAdapter<String>(new ArrayList<String>().iterator());
}