</example>
  </function>

  <function>
    <description>
      Returns Date from a given value.
    </description>
    <name>parseDate</name>
    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>
    <function-signature>java.util.Date parseDate(java.lang.String)</function-signature>
    <example>
      ${fe:parseDate(doc.tstamp)}
    </example>
  </function>

  <function>

     *
     * @param value the date string to parse
     * @return parsed Date object, or null if parsing fails
     */
    public static Date parseDate(final String value) {
        return parseDate(value, Constants.DATE_OPTIONAL_TIME);
    }

    /**
     * Parses a date string using the specified format.
     *
     * @param value the date string to parse

    @Test
    public void test_parseDate() {
        Date date;

        date = FessFunctions.parseDate("");
        assertNull(date);

        date = FessFunctions.parseDate("2004-04-01T12:34:56.123Z");
        assertEquals("2004-04-01T12:34:56.123Z", FessFunctions.formatDate(date));

        date = FessFunctions.parseDate("2004-04-01T12:34:56Z");
        assertEquals("2004-04-01T12:34:56.000Z", FessFunctions.formatDate(date));

            final Date lastModified = FessFunctions.parseDate(lastModifiedObj.toString());
            if (lastModified != null) {
                return lastModified;
            }
        } else if (lastModifiedObj instanceof final String[] lastModifieds && lastModifieds.length > 0) {
            final Date lastModified = FessFunctions.parseDate(lastModifieds[0]);
            if (lastModified != null) {

        }
        if (clazz.isAssignableFrom(Date.class)) {
            if (value instanceof Date) {
                return (T) value;
            }
            return (T) FessFunctions.parseDate(value.toString());
        }
        if (clazz.isAssignableFrom(Long.class)) {
            if (value instanceof Long) {
                return (T) value;
            }

                    return !validateDateTimeString(source.get(s));
                }).collect(Collectors.toList()));
    }

    default boolean validateDateTimeString(final Object obj) {
        if (FessFunctions.parseDate(obj.toString()) != null) {
            return true;
        }
        return false;
    }

    String getIndexAdminIntegerFields();

    default Set<String> getIndexAdminIntegerFieldSet() {