@Override
            public String getIndexAdminArrayFields() {
                return "lang,role,label,anchor,virtual_host";
            }

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

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

                .collect(Collectors.toList()));
    }

    String getIndexAdminDateFields();

    default Set<String> getIndexAdminDateFieldSet() {
        @SuppressWarnings("unchecked")
        Set<String> fieldSet = (Set<String>) propMap.get(INDEX_ADMIN_DATE_FIELD_SET);
        if (fieldSet == null) {
            fieldSet = split(getIndexAdminDateFields(), ",")

        assertEquals("alerts", fields[0]);
        assertEquals("roles", fields[1]);
    }

    @Test
    public void test_indexAdminDateFields() {
        String[] fields = fessConfig.getIndexAdminDateFields().split(",");
        assertEquals(3, fields.length);
        assertEquals("expires", fields[0]);
        assertEquals("start_time", fields[1]);
        assertEquals("end_time", fields[2]);
    }

     * comment: Date-type fields for admin in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexAdminDateFields();

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