Utilities for java.util.Date
/* Dates.java
{{IS_NOTE
Purpose:
Description:
History:
2001/12/3, Henri Chen: Created.
}}IS_NOTE
Copyright (C) 2001 Potix Corporation. All Rights Reserved.
{{IS_RIGHT
This program is distributed under GPL Version 3.0 in the hope that
it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
/**
* 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 accurarcy. That is, User must round the millisecond to some
* less precisions; or the data in that db would be inconsistence 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 milisecond, 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 previouse 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 Defult 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 Defult
* 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. eg. 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>
* Currenty, 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) {
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();
}
}
/*
* TimeZones.java
*
* {{IS_NOTE Purpose:
*
* Description:
*
* History: Mon Jun 12 12:17:03 2006, Created by tomyeh }}IS_NOTE
*
* Copyright (C) 2006 Potix Corporation. All Rights Reserved.
*
* {{IS_RIGHT }}IS_RIGHT
*/
/**
* Utilities to access time-zone.
*
* @author tomyeh
*/
class TimeZones {
private static final InheritableThreadLocal _thdTZone = new InheritableThreadLocal();
/**
* Returns the current time zone; never null. This is the time zone that every
* other objects shall use, unless they have special consideration.
*
* <p>
* Default: If {@link #setThreadLocal} was called with non-null, the value is
* returned. Otherwise, TimeZone.getDefault() is returned,
*/
public static final TimeZone getCurrent() {
final TimeZone l = (TimeZone) _thdTZone.get();
return l != null ? l : TimeZone.getDefault();
}
/**
* Sets the time-zone for the current thread only.
*
* <p>
* Each thread could have an independent time zone, called the thread time
* zone.
*
* <p>
* When Invoking this method under a thread that serves requests, remember to
* clean up the setting upon completing each request.
*
* <pre><code>
* TimeZone old = TimeZones.setThreadLocal(newValue);
* try {
* ...
* } finally {
* TimeZones.setThreadLocal(old);
* }
* </code></pre>
*
* @param timezone
* the thread time zone; null to denote no thread time zone (and the
* system's timezone will be used instead)
* @return the previous thread time zone, or null if no previous time zone
*/
public static final TimeZone setThreadLocal(TimeZone timezone) {
final TimeZone old = (TimeZone) _thdTZone.get();
_thdTZone.set(timezone);
return old;
}
/**
* Returns the time zone defined by {@link #setThreadLocal}.
*
* @since 3.0.0
* @see #getCurrent
*/
public static final TimeZone getThreadLocal() {
return (TimeZone) _thdTZone.get();
}
/**
* Returns the time by specifying the offset in minutes.
*
* <p>
* For example, the following are equivalent.
*
* <pre><code>
* TimeZone.getTimeZone("GMT+8");
* TimeZones.getTimeZone(480);
* </code></pre>
*
* @param ofsmins
* the offset in minutes.
*/
public static final TimeZone getTimeZone(int ofsmins) {
final StringBuffer sb = new StringBuffer(8).append("GMT");
if (ofsmins >= 0) {
sb.append('+');
} else {
sb.append('-');
ofsmins = -ofsmins;
}
final int hr = ofsmins / 60, min = ofsmins % 60;
if (min == 0) {
sb.append(hr);
} else {
if (hr < 10)
sb.append('0');
sb.append(hr).append(':');
if (min < 10)
sb.append('0');
sb.append(min);
}
return TimeZone.getTimeZone(sb.toString());
}
}
Related examples in the same category
