/**
  * Whether empty fields were omitted. That is, <code>omitEmptyFields</code> is set and there were
  * empty fields in the ordering.
  *
  * @return whether empty fields were omitted.
  */
 public boolean omittedEmptyFields() {
   if (!omitEmptyFields) return false;
   Set<Field> omittableFields = getOmittedEmptyFields();
   return omitEmptyFields && omittableFields.size() > 0;
 }
 /**
  * Get the set of fields from the filter's field ordering which were omitted due to being empty.
  *
  * @return the set of empty fields which were omitted from the ordering
  */
 public Set<Field> getOmittedEmptyFields() {
   Set<Field> empties = EnumSet.copyOf(columnOrdering.getFields());
   empties.retainAll(emptyFields);
   return empties;
 }