public boolean hasFieldDesc(final String fieldName) {
        assertArgumentNotEmpty("fieldName", fieldName);

        return fieldDescCache.containsKey(fieldName);
    }

    @Override
    public FieldDesc getFieldDesc(final String fieldName) {
        assertArgumentNotEmpty("fieldName", fieldName);

        final FieldDesc fieldDesc = fieldDescCache.get(fieldName);
        if (fieldDesc == null) {