Java TimeZone extractTimeZone(String strdate, Date thedate)

Description

extract Time Zone

License

Open Source License

Declaration

private static Date extractTimeZone(String strdate, Date thedate) 

Method Source Code

//package com.java2s;
// Lesser General Public License as published by the Free Software Foundation.

import java.util.Calendar;
import java.util.Date;

import java.util.TimeZone;

public class Main {
    private static Date extractTimeZone(String strdate, Date thedate) {
        // try to extract -06:00
        String tzSign = strdate.substring(strdate.length() - 6, strdate.length() - 5);
        String tzHour = strdate.substring(strdate.length() - 5, strdate.length() - 3);
        String tzMin = strdate.substring(strdate.length() - 2);
        if (tzSign.equals("-") || tzSign.equals("+")) {
            int h = Integer.parseInt(tzHour);
            int m = Integer.parseInt(tzMin);
            // NOTE: this is really plus, since perspective is from GMT
            if (tzSign.equals("+")) {
                h = -1 * h;//from ww w  . j  ava  2 s .  c  o m
                m = -1 * m;
            }
            Calendar cal = Calendar.getInstance();
            cal.setTime(thedate);
            cal.add(Calendar.HOUR_OF_DAY, h);
            cal.add(Calendar.MINUTE, m);
            // calculate according the used timezone
            cal.add(Calendar.MILLISECOND, localTimeDiff(cal.getTimeZone(), thedate));
            thedate = cal.getTime();
        }
        return thedate;
    }

    private static int localTimeDiff(TimeZone tz, Date date) {
        if (tz.inDaylightTime(date)) {
            int dstSavings = 0;
            if (tz.useDaylightTime()) {
                dstSavings = 3600000; // shortcut, JDK 1.4 allows cleaner impl
            }
            return tz.getRawOffset() + dstSavings;
        }
        return tz.getRawOffset();
    }
}

Related

1. getDateAtTimeZone(Date when, TimeZone from, TimeZone to)
2. getDateAttributes(long millisec, TimeZone tz, boolean showNumber)
3. getDateBoxValue(TimeZone zone, Date date)
4. getDateValue(TimeZone zone, Long dateBoxValue, Long timeBoxValue)