Review

class MapFieldSelector {
    /** Load field according to its associated value in fieldSelections
     * @param field a field name
     * @return the fieldSelections value that field maps to or NO_LOAD if none.
     */
    public FieldSelectorResult accept(String field) {
        FieldSelectorResult selection = (FieldSelectorResult) fieldSelections.get(field);
        return selection!=null ? selection : FieldSelectorResult.NO_LOAD;
    }

}