Java Date ISO Parse parseISO8601Date(final String dateString)

Description

Parse the date contained in the supplied string and return a UTC Calendar object.

License

Open Source License

Parameter

Parameter	Description
dateString	the string containing the date to be parsed

Exception

Parameter	Description
ParseException	if there is a problem parsing the string

Return

the parsed date as a object. The return value is always in UTC time zone. Conversion occurs when necessary.

Declaration

public static Calendar parseISO8601Date(final String dateString) throws ParseException

Method Source Code

//package com.java2s;
/*/*from w  ww  .j  a  v a  2s .  c o  m*/
 * JBoss, Home of Professional Open Source.
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors. 
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

import java.text.ParseException;

import java.util.Calendar;

import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    /**
     * Parse the date contained in the supplied string and return a UTC Calendar object. The date must follow one of the
     * standard ISO 8601 formats, of the form <code><i>datepart</i>T<i>timepart</i></code>, where
     * <code><i>datepart</i></code> is one of the following forms:
     * <p>
     * <dl>
     * <dt>YYYYMMDD</dt>
     * <dd>The 4-digit year, the 2-digit month (00-12), and the 2-digit day of the month (00-31). The month and day are
     * optional, but the month is required if the day is given.</dd>
     * <dt>YYYY-MM-DD</dt>
     * <dd>The 4-digit year, the 2-digit month (00-12), and the 2-digit day of the month (00-31). The month and day are
     * optional, but the month is required if the day is given.</dd>
     * <dt>YYYY-Www-D</dt>
     * <dd>The 4-digit year followed by 'W', the 2-digit week number (00-53), and the day of the week (1-7). The day of
     * week number is optional.</dd>
     * <dt>YYYYWwwD</dt>
     * <dd>The 4-digit year followed by 'W', the 2-digit week number (00-53), and the day of the week (1-7). The day of
     * week number is optional.</dd>
     * <dt>YYYY-DDD</dt>
     * <dd>The 4-digit year followed by the 3-digit day of the year (000-365)</dd>
     * <dt>YYYYDDD</dt>
     * <dd>The 4-digit year followed by the 3-digit day of the year (000-365)</dd>
     * </dl>
     * </p>
     * <p>
     * The <code><i>timepart</i></code> consists of one of the following forms that contain the 2-digit hour (00-24),
     * the 2-digit minutes (00-59), the 2-digit seconds (00-59), and the 1-to-3 digit milliseconds. The minutes, seconds
     * and milliseconds are optional, but any component is required if it is followed by another component (e.g.,
     * minutes are required if the seconds are given).
     * <dl>
     * <dt>hh:mm:ss.SSS</dt>
     * <dt>hhmmssSSS</dt>
     * </dl>
     * </p>
     * <p>
     * followed by one of the following time zone definitions:
     * <dt>Z</dt>
     * <dd>The uppercase or lowercase 'Z' to denote UTC time</dd>
     * <dt>&#177;hh:mm</dt>
     * <dd>The 2-digit hour and the 2-digit minute offset from UTC</dd>
     * <dt>&#177;hhmm</dt>
     * <dd>The 2-digit hour and the 2-digit minute offset from UTC</dd>
     * <dt>&#177;hh</dt>
     * <dd>The 2-digit hour offset from UTC</dd>
     * <dt>hh:mm</dt>
     * <dd>The 2-digit hour and the 2-digit minute offset from UTC</dd>
     * <dt>hhmm</dt>
     * <dd>The 2-digit hour and the 2-digit minute offset from UTC</dd>
     * <dt>hh</dt>
     * <dd>The 2-digit hour offset from UTC</dd>
     * </dl>
     * </p>
     * 
     * @param dateString
     *            the string containing the date to be parsed
     * @return the parsed date as a {@link Calendar} object. The return value is always in UTC time zone. Conversion
     *         occurs when necessary.
     * @throws ParseException
     *             if there is a problem parsing the string
     */
    public static Calendar parseISO8601Date(final String dateString) throws ParseException {
        // Example: 2008-02-16T12:30:45.123-0600
        // Example: 2008-W06-6
        // Example: 2008-053
        //
        // Group Optional Field Description
        // ----- -------- --------- ------------------------------------------
        // 1 no 2008 4 digit year as a number
        // 2 yes 02-16 or W06-6 or 053
        // 3 yes W06-6
        // 4 yes 06 2 digit week number (00-59)
        // 5 yes 6 1 digit day of week as a number (1-7)
        // 6 yes 02-16
        // 7 yes 02 2 digit month as a number (00-19)
        // 8 yes -16
        // 9 yes 16 2 digit day of month as a number (00-39)
        // 10 yes 02 2 digit month as a number (00-19)
        // 11 yes 16 2 digit day of month as a number (00-39)
        // 12 yes 234 3 digit day of year as a number (000-399)
        // 13 yes T12:30:45.123-0600
        // 14 yes 12 2 digit hour as a number (00-29)
        // 15 yes 30 2 digit minute as a number (00-59)
        // 16 yes :45.123
        // 17 yes 45 2 digit second as a number (00-59)
        // 18 yes .123
        // 19 yes 123 1, 2 or 3 digit milliseconds as a number (000-999)
        // 20 yes -0600
        // 21 yes Z The letter 'Z' if in UTC
        // 22 yes -06 1 or 2 digit time zone hour offset as a signed number
        // 23 yes + the plus or minus in the time zone offset
        // 24 yes 00 1 or 2 digit time zone hour offset as an unsigned number (00-29)
        // 25 yes 00 1 or 2 digit time zone minute offset as a number (00-59)
        final String regex = "^(\\d{4})-?(([wW]([012345]\\d)-?([1234567])?)|(([01]\\d)(-([0123]\\d))?)|([01]\\d)([0123]\\d)|([0123]\\d\\d))?(T([012]\\d):?([012345]\\d)?(:?([012345]\\d)(.(\\d{1,3}))?)?)?((Z)|(([+-])(\\d{2})):?(\\d{2})?)?$";
        final Pattern pattern = Pattern.compile(regex);
        final Matcher matcher = pattern.matcher(dateString);
        if (!matcher.matches()) {
            throw new ParseException("error while parsing iso8601 date: " + dateString, 0);
        }
        String year = matcher.group(1);
        String week = matcher.group(4);
        String dayOfWeek = matcher.group(5);
        String month = matcher.group(7);
        if (month == null)
            month = matcher.group(10);
        String dayOfMonth = matcher.group(9);
        if (dayOfMonth == null)
            dayOfMonth = matcher.group(11);
        String dayOfYear = matcher.group(12);
        String hourOfDay = matcher.group(14);
        String minutesOfHour = matcher.group(15);
        String seconds = matcher.group(17);
        String milliseconds = matcher.group(19);
        String timeZoneSign = matcher.group(23);
        String timeZoneHour = matcher.group(24);
        String timeZoneMinutes = matcher.group(25);

        boolean localeTime = true;
        if (timeZoneHour != null) {
            localeTime = false;
        }
        if (matcher.group(21) != null) {
            localeTime = false;
            timeZoneHour = "00";
            timeZoneMinutes = "00";
        }

        // Create the calendar object and start setting the fields ...
        Calendar calendar;
        if (localeTime) {
            calendar = Calendar.getInstance();
        } else {
            calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
        }
        calendar.clear();

        // And start setting the fields. Note that Integer.parseInt should never fail, since we're checking for null and
        // the
        // regular expression should only have digits in these strings!
        if (year != null)
            calendar.set(Calendar.YEAR, Integer.parseInt(year));
        if (month != null) {
            calendar.set(Calendar.MONTH, Integer.parseInt(month) - 1); // month is zero-based!
            if (dayOfMonth != null)
                calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(dayOfMonth));
        } else if (week != null) {
            calendar.set(Calendar.WEEK_OF_YEAR, Integer.parseInt(week));
            if (dayOfWeek != null)
                calendar.set(Calendar.DAY_OF_WEEK, Integer.parseInt(dayOfWeek));
        } else if (dayOfYear != null) {
            calendar.set(Calendar.DAY_OF_YEAR, Integer.parseInt(dayOfYear));
        }
        if (hourOfDay != null)
            calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(hourOfDay));
        if (minutesOfHour != null)
            calendar.set(Calendar.MINUTE, Integer.parseInt(minutesOfHour));
        if (seconds != null)
            calendar.set(Calendar.SECOND, Integer.parseInt(seconds));
        if (milliseconds != null)
            calendar.set(Calendar.MILLISECOND, Integer.parseInt(milliseconds));
        if (timeZoneHour != null) {
            int zoneOffsetInMillis = Integer.parseInt(timeZoneHour) * 60 * 60 * 1000;
            if ("-".equals(timeZoneSign))
                zoneOffsetInMillis *= -1;
            if (timeZoneMinutes != null) {
                int minuteOffsetInMillis = Integer.parseInt(timeZoneMinutes) * 60 * 1000;
                if (zoneOffsetInMillis < 0) {
                    zoneOffsetInMillis -= minuteOffsetInMillis;
                } else {
                    zoneOffsetInMillis += minuteOffsetInMillis;
                }
            }
            calendar.set(Calendar.ZONE_OFFSET, zoneOffsetInMillis);
        }
        // convert to utc time
        Calendar result = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
        result.setTime(calendar.getTime());
        return result;
    }
}