/* Dates.java
Purpose:
Description:
History:
2001/12/3, Henri Chen: Created.
Copyright (C) 2001 Potix Corporation. All Rights Reserved.
{{IS_RIGHT
This program is distributed under LGPL Version 2.1 in the hope that
it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.util;
import java.util.Date;
import java.util.Calendar;
import java.util.TimeZone;
import java.util.Locale;
/**
* Utilities for java.util.Date
*
* @author henrichen
* @author tomyeh
*/
public class Dates {
/**
* Truncates date to the nearest precision milliseconds. MS SQLServer2000
* with only the maximum accuracy of 1/300 seconds would not be able to
* store up to one millisecond accuracy. That is, User must round the
* millisecond to some less precisions; or the data in that db would be
* inconsistent with that in memory.
* It is useful to store a Date object in a database.
* Without rounding, if you want to get it back and compare with the
* one in the memory. See {@link #now} for details.
*
* @param precision the divider of the precision(e.g. 10 for precision
* of 10 milliseconds;i.e. all millisecond less than 10 would be truncated)
* @see #now
* @see #round(long, int)
*/
public static final Date round(Date date, int precision) {
date.setTime(round(date.getTime(), precision));
return date;
}
/**
* Rounds a date represented in long to the specified precision of
* milliseconds.
*
* @param time the date represented in long.
* @param precision the divider of the precision(e.g. 10 for precision
* of 10 milliseconds;i.e. all millisecond less than 10 would be truncated)
* @see #now
* @see #round(Date, int)
*/
public static final long round(long time, int precision) {
return time - (time % precision);
}
/** Tests whether a date is rounded.
* It is mainly used for debugging.
*/
public static final boolean isRounded(Date date, int precision) {
return (date.getTime() % precision) == 0;
}
/** Returns the current time but rounding to the specified precision
* of milliseconds. It is useful if you want to create the current time
* which will be stored in the database and want to compare it with
* something with what you store in the database. Otherwise, that you
* get back the one you store might be different, because the resolution
* of database timestamp is usually less than one millisecond,
* e.g., MS SQL: 0.003 second.
*
* <p>If you don't cache it in the memory (remember entity beans
* always cache by the container), you don't need to round. If you
* are not sure, round it.
*
* @see #round(Date, int)
*/
public static final Date now(int precision) {
return new Date(round(System.currentTimeMillis(), precision));
}
/** Returns the current time without rounding.
*/
public static final Date now() {
return new Date();
}
/** Returns today by setting time to 0:0:0.
*/
public static final Date today() {
return beginOfDate(new Date(), null);
}
/**
* Given a date, return the previous date of the given date (24 hrs before).
*/
final public static Date previousDate(Date when) {
long time = when.getTime() - 24*60*60*1000;
return new Date(time);
}
/**
* Return the beginning date of this month.
*/
final public static Date beginOfMonth() {
return beginOfMonth(new Date(), null);
}
/**
* Given a date, a proper TimeZone, return the beginning date of the
* month of the specified date and TimeZone.
* If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static Date beginOfMonth(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int year = cal.get(Calendar.YEAR);
final int month = cal.get(Calendar.MONTH);
cal.clear();
cal.set(year, month, 1);
return cal.getTime();
}
/**
* Return the ending date of this month.
*/
final public static Date endOfMonth() {
return endOfMonth(new Date(), null);
}
/**
* Given a date, a proper TimeZone, return the ending date of the
* month of the specified date and TimeZone.
* If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static Date endOfMonth(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int year = cal.get(Calendar.YEAR);
final int month = cal.get(Calendar.MONTH);
final int monthDays = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
cal.clear();
cal.set(year, month, monthDays + 1);
cal.setTimeInMillis(cal.getTimeInMillis() - 1);
return cal.getTime();
}
/**
* Whether the given date in the specified TimeZone is the last day of that
* month. If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static boolean isEndOfMonth(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int day = cal.get(Calendar.DAY_OF_MONTH);
final int maxDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
return day == maxDay;
}
/**
* Whether the given date in the specified TimeZone is the first day of that
* month. If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static boolean isBeginOfMonth(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int day = cal.get(Calendar.DAY_OF_MONTH);
return day == 1;
}
/**
* Given a date, a proper TimeZone, return the beginning date of
* the specified date and TimeZone. If TimeZone is null, meaning use Default
* TimeZone of the JVM.
*/
final public static Date beginOfDate(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
final int day = cal.get(Calendar.DAY_OF_MONTH);
final int year = cal.get(Calendar.YEAR);
final int month = cal.get(Calendar.MONTH);
cal.clear();
cal.set(year, month, day);
return cal.getTime();
}
/**
* Given a date, a proper TimeZone, return the last millisecond date of
* the specified date and TimeZone. If TimeZone is null, meaning use Default
* TimeZone of the JVM.
*/
final public static Date endOfDate(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
final int day = cal.get(Calendar.DAY_OF_MONTH);
final int year = cal.get(Calendar.YEAR);
final int month = cal.get(Calendar.MONTH);
cal.clear();
cal.set(year, month, day + 1);
cal.setTimeInMillis(cal.getTimeInMillis() - 1);
return cal.getTime();
}
/**
* Return the beginning date of this year.
*/
final public static Date beginOfYear() {
return beginOfYear(new Date(), null);
}
/**
* Given a date, a proper TimeZone, return the beginning date of the
* month of the specified date and TimeZone.
* If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static Date beginOfYear(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int year = cal.get(Calendar.YEAR);
cal.clear();
cal.set(year, Calendar.JANUARY, 1);
return cal.getTime();
}
/**
* Return the ending date of this year.
*/
final public static Date endOfYear() {
return endOfYear(new Date(), null);
}
/**
* Given a date, a proper TimeZone, return the ending date of the
* month of the specified date and TimeZone.
* If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static Date endOfYear(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int year = cal.get(Calendar.YEAR);
cal.clear();
cal.set(year + 1, Calendar.JANUARY, 1);
cal.setTimeInMillis(cal.getTimeInMillis() - 1);
return cal.getTime();
}
/**
* Return the ending date of this year.
*/
final public static short twoMonthShort() {
return twoMonthShort(new Date(), null);
}
/**
* Given a date, a proper TimeZone, return the two month int. e.g. 1, 3, 5, 7, 9, 11.
* If TimeZone is null, meaning use default TimeZone of the JVM.
*/
final public static short twoMonthShort(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
final int month = (cal.get(Calendar.MONTH) / 2) * 2 + 1;
return (short)month;
}
/**
* Get the year of a date.
* @param when The date.
* @param tz The time zone; if null, the current time zone is assumed.
* @see #localizedYearOfDate
*/
public static final int yearOfDate(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
return cal.get(Calendar.YEAR);
}
/**
* Get the year of a date in the specified locale.
*
* <p>Currently, only Locale.ZH_TW is supported, i.e.,
* "year - 1911" and it's may be less than 0. Otherwise, it is the same
* as {@link #yearOfDate}.
*
* @param when The date.
* @param locale the locale; if null, the current locale is assumed.
* @param tz The time zone; if null, the current time zone is assumed.
* @see #yearOfDate
*/
public static final int
localizedYearOfDate(Date when, Locale locale, TimeZone tz) {
if (locale == null)
locale = Locales.getCurrent();
final int year = yearOfDate(when, tz);
if (locale.equals(Locale.TAIWAN))
return year - 1911;
return year;
}
/**
* Get the month of a date. The first month of the year is JANUARY which is 0.
* @param when The date.
* @param tz The time zone; if null, the current time zone is assumed.
*/
public static final int monthOfDate(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
return cal.get(Calendar.MONTH);
}
/**
* Get the month of a date. The first month of the year is JANUARY which is 1.
* @param when The date.
* @param tz The time zone; if null, the current time zone is assumed.
*/
public static final int monthOfDatePlus1(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
return cal.get(Calendar.MONTH) + 1;
}
/**
* Get the day of month of a date. The first day of the month has value 1.
* @param when The date.
* @param tz The time zone; if null, the current time zone is assumed.
*/
public static final int dayMonthOfDate(Date when, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime()); //don't call cal.setTime(Date) which will reset the TimeZone.
return cal.get(Calendar.DAY_OF_MONTH);
}
/**
* Date Arithmetic function. Adds the specified (signed) amount of time to the given date,
* based on the calendar's rules.
* @param when The based date.
* @param tz The time zone; if null, the current time zone is assumed.
* @param field The time field.
* @param amount The amount of date or time to be added to the field.
*/
public static final Date add(Date when, TimeZone tz, int field, int amount) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(when.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
cal.add(field, amount);
return cal.getTime();
}
/**
* Date Arithmetic function (date2 - date1). subtract a date from another date, return the
* difference as the required fields. E.g. if specified Calendar.Date, the
* smaller range of fields is ignored and this method return the difference
* of days.
*
* @param date2 The date2.
* @param tz The time zone.
* @param field The time field; e.g., Calendar.DATE, Calendar.YEAR, it's default value is Calendar.DATE
* @param date1 The date1.
*/
public static final long
subtract(Date date2, TimeZone tz, int field, Date date1) {
if (tz == null)
tz = TimeZones.getCurrent();
boolean negative = false;
if (date1.after(date2)) {
negative = true;
final Date d = date1;
date1 = date2;
date2 = d;
}
final Calendar cal1 = Calendar.getInstance(tz);
cal1.setTimeInMillis(date1.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
final Calendar cal2 = Calendar.getInstance(tz);
cal2.setTimeInMillis(date2.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
int year1 = cal1.get(Calendar.YEAR);
int year2 = cal2.get(Calendar.YEAR);
switch(field) {
case Calendar.YEAR:
{
return negative ? (year1-year2) : (year2-year1);
}
case Calendar.MONTH:
{
int month1 = cal1.get(Calendar.MONTH);
int month2 = cal2.get(Calendar.MONTH);
int months = 12 * (year2 - year1) + month2 - month1;
return negative ? -months : months;
}
case Calendar.HOUR:
{
long time1 = date1.getTime();
long time2 = date2.getTime();
long min1 = (time1 < 0 ? (time1 - (1000 * 60 * 60 - 1)) : time1 ) / (1000 * 60 * 60);
long min2 = (time2 < 0 ? (time2 - (1000 * 60 * 60 - 1)) : time2 ) / (1000 * 60 * 60);
return negative ? (min1 - min2) : (min2 - min1);
}
case Calendar.MINUTE:
{
long time1 = date1.getTime();
long time2 = date2.getTime();
long min1 = (time1 < 0 ? (time1 - (1000 * 60 - 1)) : time1 ) / (1000 * 60);
long min2 = (time2 < 0 ? (time2 - (1000 * 60 - 1)) : time2 ) / (1000 * 60);
return negative ? (min1 - min2) : (min2 - min1);
}
case Calendar.SECOND:
{
long time1 = date1.getTime();
long time2 = date2.getTime();
long sec1 = (time1 < 0 ? (time1 - (1000 - 1)) : time1 ) / 1000;
long sec2 = (time2 < 0 ? (time2 - (1000 - 1)) : time2 ) / 1000;
return negative ? (sec1 - sec2) : (sec2 - sec1);
}
case Calendar.MILLISECOND:
{
return negative ?
(date1.getTime() - date2.getTime()):
(date2.getTime() - date1.getTime());
}
case Calendar.DATE:
default: /*default, like -1*/
{
int day1 = cal1.get(Calendar.DAY_OF_YEAR);
int day2 = cal2.get(Calendar.DAY_OF_YEAR);
int maxDay1 = year1 == year2 ?
0 : cal1.getActualMaximum(Calendar.DAY_OF_YEAR);
int days = maxDay1 - day1 + day2;
final Calendar cal = Calendar.getInstance(tz);
for(int year = year1+1; year < year2; year++) {
cal.set(Calendar.YEAR, year);
days += cal.getActualMaximum(Calendar.DAY_OF_YEAR);
}
return negative ? -days : days;
}
}
}
/**
* merge the date part and time part of two specified dates into a date.
* @param datePart The date part date.
* @param timePart The time part date.
* @param tz The time zone.
*/
public static final Date merge(Date datePart, Date timePart, TimeZone tz) {
if (tz == null)
tz = TimeZones.getCurrent();
final Calendar dateCal = Calendar.getInstance(tz);
dateCal.setTimeInMillis(datePart.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
final Calendar timeCal = Calendar.getInstance(tz);
timeCal.setTimeInMillis(timePart.getTime());//don't call cal.setTime(Date) which will reset the TimeZone.
final int hour = timeCal.get(Calendar.HOUR);
final int minute = timeCal.get(Calendar.MINUTE);
final int second = timeCal.get(Calendar.SECOND);
final int msillisecond = timeCal.get(Calendar.MILLISECOND);
dateCal.set(Calendar.HOUR, hour);
dateCal.set(Calendar.MINUTE, minute);
dateCal.set(Calendar.SECOND, second);
dateCal.set(Calendar.MILLISECOND, msillisecond);
return dateCal.getTime();
}
/**
* Returns the timezone offset.
* @param timezone The time zone.
* @param date
* @return long
*/
public static final long getTimezoneOffset(TimeZone timezone, Date date) {
return timezone.getRawOffset() + (timezone.inDaylightTime(date) ? timezone.getDSTSavings(): 0);
}
}