@Override
            public String getIndexAdminDateFields() {
                return "expires,created,timestamp,last_modified";
            }

            @Override
            public String getIndexAdminIntegerFields() {
                return "";
            }

            @Override
            public String getIndexAdminLongFields() {
                return "content_length,favorite_count,click_count";
            }

        }
        return false;
    }

    String getIndexAdminIntegerFields();

    default Set<String> getIndexAdminIntegerFieldSet() {
        @SuppressWarnings("unchecked")
        Set<String> fieldSet = (Set<String>) propMap.get(INDEX_ADMIN_INTEGER_FIELD_SET);
        if (fieldSet == null) {
            fieldSet = split(getIndexAdminIntegerFields(), ",")

     * The value is, e.g.  <br>
     * comment: Integer-type fields for admin in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexAdminIntegerFields();

    /**
     * Get the value for the key 'index.admin.integer.fields' as {@link Integer}. <br>
     * The value is, e.g.  <br>
     * comment: Integer-type fields for admin in the index.