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studio.raptor.sqlparser.fast.util.DateTimeUtils Maven / Gradle / Ivy

/*
 * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0, and the
 * EPL 1.0 (http://h2database.com/html/license.html). Initial Developer: H2
 * Group Iso8601: Initial Developer: Robert Rathsack (firstName dot lastName at
 * gmx dot de)
 */
package studio.raptor.sqlparser.fast.util;

import java.sql.Date;
import java.sql.Time;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
import studio.raptor.sqlparser.fast.api.ErrorCode;
import studio.raptor.sqlparser.fast.message.ParseException;
import studio.raptor.sqlparser.fast.value.Value;
import studio.raptor.sqlparser.fast.value.ValueNull;
import studio.raptor.sqlparser.fast.value.ValueTimestamp;
import studio.raptor.sqlparser.fast.value.ValueDate;
import studio.raptor.sqlparser.fast.value.ValueTime;

/**
 * This utility class contains time conversion functions.
 * 

* Date value: a bit field with bits for the year, month, and day. Absolute day: * the day number (0 means 1970-01-01). */ public class DateTimeUtils { /** * The number of milliseconds per day. */ public static final long MILLIS_PER_DAY = 24 * 60 * 60 * 1000L; private static final long NANOS_PER_DAY = MILLIS_PER_DAY * 1000000; private static final int SHIFT_YEAR = 9; private static final int SHIFT_MONTH = 5; private static final int[] NORMAL_DAYS_PER_MONTH = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; /** * Offsets of month within a year, starting with March, April,... */ private static final int[] DAYS_OFFSET = {0, 31, 61, 92, 122, 153, 184, 214, 245, 275, 306, 337, 366}; /** * The thread local. Can not override initialValue because this would result * in an inner class, which would not be garbage collected in a web * container, and prevent the class loader of H2 from being garbage * collected. Using a ThreadLocal on a system class like Calendar does not * have that problem, and while it is still a small memory leak, it is not a * class loader memory leak. */ private static final ThreadLocal CACHED_CALENDAR = new ThreadLocal(); /** * A cached instance of Calendar used when a timezone is specified. */ private static final ThreadLocal CACHED_CALENDAR_NON_DEFAULT_TIMEZONE = new ThreadLocal(); /** * Observed JVM behaviour is that if the timezone of the host computer is * changed while the JVM is running, the zone offset does not change but * keeps the initial value. So it is correct to measure this once and use * this value throughout the JVM's lifecycle. In any case, it is safer to * use a fixed value throughout the duration of the JVM's life, rather than * have this offset change, possibly midway through a long-running query. */ private static int zoneOffsetMillis = Calendar.getInstance() .get(Calendar.ZONE_OFFSET); private DateTimeUtils() { // utility class } /** * Reset the cached calendar for default timezone, for example after * changing the default timezone. */ public static void resetCalendar() { CACHED_CALENDAR.remove(); zoneOffsetMillis = Calendar.getInstance().get(Calendar.ZONE_OFFSET); } /** * Get a calendar for the default timezone. * * @return a calendar instance. A cached instance is returned where possible */ private static Calendar getCalendar() { Calendar c = CACHED_CALENDAR.get(); if (c == null) { c = Calendar.getInstance(); CACHED_CALENDAR.set(c); } c.clear(); return c; } /** * Get a calendar for the given timezone. * * @param tz timezone for the calendar, is never null * @return a calendar instance. A cached instance is returned where possible */ private static Calendar getCalendar(TimeZone tz) { Calendar c = CACHED_CALENDAR_NON_DEFAULT_TIMEZONE.get(); if (c == null || !c.getTimeZone().equals(tz)) { c = Calendar.getInstance(tz); CACHED_CALENDAR_NON_DEFAULT_TIMEZONE.set(c); } c.clear(); return c; } /** * Convert the date to the specified time zone. * * @param value the date (might be ValueNull) * @param calendar the calendar * @return the date using the correct time zone */ public static Date convertDate(Value value, Calendar calendar) { if (value == ValueNull.INSTANCE) { return null; } ValueDate d = (ValueDate) value.convertTo(Value.DATE); Calendar cal = (Calendar) calendar.clone(); cal.clear(); cal.setLenient(true); long dateValue = d.getDateValue(); setCalendarFields(cal, yearFromDateValue(dateValue), monthFromDateValue(dateValue), dayFromDateValue(dateValue), 0, 0, 0, 0); long ms = cal.getTimeInMillis(); return new Date(ms); } /** * Convert the time to the specified time zone. * * @param value the time (might be ValueNull) * @param calendar the calendar * @return the time using the correct time zone */ public static Time convertTime(Value value, Calendar calendar) { if (value == ValueNull.INSTANCE) { return null; } ValueTime t = (ValueTime) value.convertTo(Value.TIME); Calendar cal = (Calendar) calendar.clone(); cal.clear(); cal.setLenient(true); long nanos = t.getNanos(); long millis = nanos / 1000000; nanos -= millis * 1000000; long s = millis / 1000; millis -= s * 1000; long m = s / 60; s -= m * 60; long h = m / 60; m -= h * 60; setCalendarFields(cal, 1970, 1, 1, (int) h, (int) m, (int) s, (int) millis); long ms = cal.getTimeInMillis(); return new Time(ms); } /** * Convert the timestamp to the specified time zone. * * @param value the timestamp (might be ValueNull) * @param calendar the calendar * @return the timestamp using the correct time zone */ public static Timestamp convertTimestamp(Value value, Calendar calendar) { if (value == ValueNull.INSTANCE) { return null; } ValueTimestamp ts = (ValueTimestamp) value.convertTo(Value.TIMESTAMP); Calendar cal = (Calendar) calendar.clone(); cal.clear(); cal.setLenient(true); long dateValue = ts.getDateValue(); long nanos = ts.getTimeNanos(); long millis = nanos / 1000000; nanos -= millis * 1000000; long s = millis / 1000; millis -= s * 1000; long m = s / 60; s -= m * 60; long h = m / 60; m -= h * 60; setCalendarFields(cal, yearFromDateValue(dateValue), monthFromDateValue(dateValue), dayFromDateValue(dateValue), (int) h, (int) m, (int) s, (int) millis); long ms = cal.getTimeInMillis(); Timestamp x = new Timestamp(ms); x.setNanos((int) (nanos + millis * 1000000)); return x; } /** * Convert a java.util.Date using the specified calendar. * * @param x the date * @param calendar the calendar * @return the date */ public static ValueDate convertDate(Date x, Calendar calendar) { if (calendar == null) { throw ParseException.getInvalidValueException("calendar", null); } Calendar cal = (Calendar) calendar.clone(); cal.setTimeInMillis(x.getTime()); long dateValue = dateValueFromCalendar(cal); return ValueDate.fromDateValue(dateValue); } /** * Convert the time using the specified calendar. * * @param x the time * @param calendar the calendar * @return the time */ public static ValueTime convertTime(Time x, Calendar calendar) { if (calendar == null) { throw ParseException.getInvalidValueException("calendar", null); } Calendar cal = (Calendar) calendar.clone(); cal.setTimeInMillis(x.getTime()); long nanos = nanosFromCalendar(cal); return ValueTime.fromNanos(nanos); } /** * Convert a date to the specified time zone. * * @param x the date to convert * @param target the calendar with the target timezone * @return the milliseconds in UTC */ public static long convertToLocal(java.util.Date x, Calendar target) { if (target == null) { throw ParseException.getInvalidValueException("calendar", null); } target = (Calendar) target.clone(); Calendar local = Calendar.getInstance(); synchronized (local) { local.setTime(x); convertTime(local, target); } return target.getTime().getTime(); } private static void convertTime(Calendar from, Calendar to) { to.set(Calendar.ERA, from.get(Calendar.ERA)); to.set(Calendar.YEAR, from.get(Calendar.YEAR)); to.set(Calendar.MONTH, from.get(Calendar.MONTH)); to.set(Calendar.DAY_OF_MONTH, from.get(Calendar.DAY_OF_MONTH)); to.set(Calendar.HOUR_OF_DAY, from.get(Calendar.HOUR_OF_DAY)); to.set(Calendar.MINUTE, from.get(Calendar.MINUTE)); to.set(Calendar.SECOND, from.get(Calendar.SECOND)); to.set(Calendar.MILLISECOND, from.get(Calendar.MILLISECOND)); } /** * Convert the timestamp using the specified calendar. * * @param x the time * @param calendar the calendar * @return the timestamp */ public static ValueTimestamp convertTimestamp(Timestamp x, Calendar calendar) { if (calendar == null) { throw ParseException.getInvalidValueException("calendar", null); } Calendar cal = (Calendar) calendar.clone(); cal.setTimeInMillis(x.getTime()); long dateValue = dateValueFromCalendar(cal); long nanos = nanosFromCalendar(cal); nanos += x.getNanos() % 1000000; return ValueTimestamp.fromDateValueAndNanos(dateValue, nanos); } /** * Parse a date string. The format is: [+|-]year-month-day * * @param s the string to parse * @param start the parse index start * @param end the parse index end * @return the date value * @throws IllegalArgumentException if there is a problem */ public static long parseDateValue(String s, int start, int end) { if (s.charAt(start) == '+') { // +year start++; } // start at position 1 to support "-year" int s1 = s.indexOf('-', start + 1); int s2 = s.indexOf('-', s1 + 1); if (s1 <= 0 || s2 <= s1) { throw new IllegalArgumentException(s); } int year = Integer.parseInt(s.substring(start, s1)); int month = Integer.parseInt(s.substring(s1 + 1, s2)); int day = Integer.parseInt(s.substring(s2 + 1, end)); if (!isValidDate(year, month, day)) { throw new IllegalArgumentException(year + "-" + month + "-" + day); } return dateValue(year, month, day); } /** * Parse a time string. The format is: [-]hour:minute:second[.nanos] or * alternatively [-]hour.minute.second[.nanos]. * * @param s the string to parse * @param start the parse index start * @param end the parse index end * @param timeOfDay whether the result need to be within 0 (inclusive) and 1 day (exclusive) * @return the time in nanoseconds * @throws IllegalArgumentException if there is a problem */ public static long parseTimeNanos(String s, int start, int end, boolean timeOfDay) { int hour = 0, minute = 0, second = 0; long nanos = 0; int s1 = s.indexOf(':', start); int s2 = s.indexOf(':', s1 + 1); int s3 = s.indexOf('.', s2 + 1); if (s1 <= 0 || s2 <= s1) { // if first try fails try to use IBM DB2 time format // [-]hour.minute.second[.nanos] s1 = s.indexOf('.', start); s2 = s.indexOf('.', s1 + 1); s3 = s.indexOf('.', s2 + 1); if (s1 <= 0 || s2 <= s1) { throw new IllegalArgumentException(s); } } boolean negative; hour = Integer.parseInt(s.substring(start, s1)); if (hour < 0) { if (timeOfDay) { throw new IllegalArgumentException(s); } negative = true; hour = -hour; } else { negative = false; } minute = Integer.parseInt(s.substring(s1 + 1, s2)); if (s3 < 0) { second = Integer.parseInt(s.substring(s2 + 1, end)); } else { second = Integer.parseInt(s.substring(s2 + 1, s3)); String n = (s.substring(s3 + 1, end) + "000000000").substring(0, 9); nanos = Integer.parseInt(n); } if (hour >= 2000000 || minute < 0 || minute >= 60 || second < 0 || second >= 60) { throw new IllegalArgumentException(s); } if (timeOfDay && hour >= 24) { throw new IllegalArgumentException(s); } nanos += ((((hour * 60L) + minute) * 60) + second) * 1000000000; return negative ? -nanos : nanos; } /** * Calculate the milliseconds since 1970-01-01 (UTC) for the given date and * time (in the specified timezone). * * @param tz the timezone of the parameters, or null for the default timezone * @param year the absolute year (positive or negative) * @param month the month (1-12) * @param day the day (1-31) * @param hour the hour (0-23) * @param minute the minutes (0-59) * @param second the number of seconds (0-59) * @param millis the number of milliseconds * @return the number of milliseconds (UTC) */ public static long getMillis(TimeZone tz, int year, int month, int day, int hour, int minute, int second, int millis) { try { return getTimeTry(false, tz, year, month, day, hour, minute, second, millis); } catch (IllegalArgumentException e) { // special case: if the time simply doesn't exist because of // daylight saving time changes, use the lenient version String message = e.toString(); if (message.indexOf("HOUR_OF_DAY") > 0) { if (hour < 0 || hour > 23) { throw e; } return getTimeTry(true, tz, year, month, day, hour, minute, second, millis); } else if (message.indexOf("DAY_OF_MONTH") > 0) { int maxDay; if (month == 2) { maxDay = new GregorianCalendar().isLeapYear(year) ? 29 : 28; } else { maxDay = 30 + ((month + (month > 7 ? 1 : 0)) & 1); } if (day < 1 || day > maxDay) { throw e; } // DAY_OF_MONTH is thrown for years > 2037 // using the timezone Brasilia and others, // for example for 2042-10-12 00:00:00. hour += 6; return getTimeTry(true, tz, year, month, day, hour, minute, second, millis); } else { return getTimeTry(true, tz, year, month, day, hour, minute, second, millis); } } } private static long getTimeTry(boolean lenient, TimeZone tz, int year, int month, int day, int hour, int minute, int second, int millis) { Calendar c; if (tz == null) { c = getCalendar(); } else { c = getCalendar(tz); } c.setLenient(lenient); setCalendarFields(c, year, month, day, hour, minute, second, millis); return c.getTime().getTime(); } private static void setCalendarFields(Calendar cal, int year, int month, int day, int hour, int minute, int second, int millis) { if (year <= 0) { cal.set(Calendar.ERA, GregorianCalendar.BC); cal.set(Calendar.YEAR, 1 - year); } else { cal.set(Calendar.ERA, GregorianCalendar.AD); cal.set(Calendar.YEAR, year); } // january is 0 cal.set(Calendar.MONTH, month - 1); cal.set(Calendar.DAY_OF_MONTH, day); cal.set(Calendar.HOUR_OF_DAY, hour); cal.set(Calendar.MINUTE, minute); cal.set(Calendar.SECOND, second); cal.set(Calendar.MILLISECOND, millis); } /** * Get the specified field of a date, however with years normalized to * positive or negative, and month starting with 1. * * @param d the date * @param field the field type * @return the value */ public static int getDatePart(java.util.Date d, int field) { Calendar c = getCalendar(); c.setTime(d); if (field == Calendar.YEAR) { return getYear(c); } int value = c.get(field); if (field == Calendar.MONTH) { return value + 1; } return value; } /** * Get the year (positive or negative) from a calendar. * * @param calendar the calendar * @return the year */ private static int getYear(Calendar calendar) { int year = calendar.get(Calendar.YEAR); if (calendar.get(Calendar.ERA) == GregorianCalendar.BC) { year = 1 - year; } return year; } /** * Get the number of milliseconds since 1970-01-01 in the local timezone, * but without daylight saving time into account. * * @param d the date * @return the milliseconds */ public static long getTimeLocalWithoutDst(java.util.Date d) { return d.getTime() + zoneOffsetMillis; } /** * Convert the number of milliseconds since 1970-01-01 in the local timezone * to UTC, but without daylight saving time into account. * * @param millis the number of milliseconds in the local timezone * @return the number of milliseconds in UTC */ public static long getTimeUTCWithoutDst(long millis) { return millis - zoneOffsetMillis; } /** * Return the day of week according to the ISO 8601 specification. Week * starts at Monday. See also http://en.wikipedia.org/wiki/ISO_8601 * * @param date the date object which day of week should be calculated * @return the day of the week, Monday as 1 to Sunday as 7 * @author Robert Rathsack */ public static int getIsoDayOfWeek(java.util.Date date) { Calendar cal = Calendar.getInstance(); cal.setTimeInMillis(date.getTime()); int val = cal.get(Calendar.DAY_OF_WEEK) - 1; return val == 0 ? 7 : val; } /** * Returns the week of the year according to the ISO 8601 specification. The * spec defines the first week of the year as the week which contains at * least 4 days of the new year. The week starts at Monday. Therefore * December 29th - 31th could belong to the next year and January 1st - 3th * could belong to the previous year. If January 1st is on Thursday (or * earlier) it belongs to the first week, otherwise to the last week of the * previous year. Hence January 4th always belongs to the first week while * the December 28th always belongs to the last week. * * @param date the date object which week of year should be calculated * @return the week of the year * @author Robert Rathsack */ public static int getIsoWeek(java.util.Date date) { Calendar c = Calendar.getInstance(); c.setTimeInMillis(date.getTime()); c.setFirstDayOfWeek(Calendar.MONDAY); c.setMinimalDaysInFirstWeek(4); return c.get(Calendar.WEEK_OF_YEAR); } /** * Returns the year according to the ISO week definition. * * @param date the date object which year should be calculated * @return the year * @author Robert Rathsack */ public static int getIsoYear(java.util.Date date) { Calendar cal = Calendar.getInstance(); cal.setTimeInMillis(date.getTime()); cal.setFirstDayOfWeek(Calendar.MONDAY); cal.setMinimalDaysInFirstWeek(4); int year = getYear(cal); int month = cal.get(Calendar.MONTH); int week = cal.get(Calendar.WEEK_OF_YEAR); if (month == 0 && week > 51) { year--; } else if (month == 11 && week == 1) { year++; } return year; } /** * Formats a date using a format string. * * @param date the date to format * @param format the format string * @param locale the locale * @param timeZone the timezone * @return the formatted date */ public static String formatDateTime(java.util.Date date, String format, String locale, String timeZone) { SimpleDateFormat dateFormat = getDateFormat(format, locale, timeZone); synchronized (dateFormat) { return dateFormat.format(date); } } /** * Parses a date using a format string. * * @param date the date to parse * @param format the parsing format * @param locale the locale * @param timeZone the timeZone * @return the parsed date */ public static java.util.Date parseDateTime(String date, String format, String locale, String timeZone) { SimpleDateFormat dateFormat = getDateFormat(format, locale, timeZone); try { synchronized (dateFormat) { return dateFormat.parse(date); } } catch (Exception e) { // ParseException throw ParseException.get(ErrorCode.PARSE_ERROR_1, e, date); } } private static SimpleDateFormat getDateFormat(String format, String locale, String timeZone) { try { // currently, a new instance is create for each call // however, could cache the last few instances SimpleDateFormat df; if (locale == null) { df = new SimpleDateFormat(format); } else { Locale l = new Locale(locale); df = new SimpleDateFormat(format, l); } if (timeZone != null) { df.setTimeZone(TimeZone.getTimeZone(timeZone)); } return df; } catch (Exception e) { throw ParseException.get(ErrorCode.PARSE_ERROR_1, e, format + "/" + locale + "/" + timeZone); } } /** * Verify if the specified date is valid. * * @param year the year * @param month the month (January is 1) * @param day the day (1 is the first of the month) * @return true if it is valid */ public static boolean isValidDate(int year, int month, int day) { if (month < 1 || month > 12 || day < 1) { return false; } if (year > 1582) { // Gregorian calendar if (month != 2) { return day <= NORMAL_DAYS_PER_MONTH[month]; } // February if ((year & 3) != 0) { return day <= 28; } return day <= ((year % 100 != 0) || (year % 400 == 0) ? 29 : 28); } else if (year == 1582 && month == 10) { // special case: days 1582-10-05 .. 1582-10-14 don't exist return day <= 31 && (day < 5 || day > 14); } if (month != 2 && day <= NORMAL_DAYS_PER_MONTH[month]) { return true; } return day <= ((year & 3) != 0 ? 28 : 29); } /** * Convert an encoded date value to a java.util.Date, using the default * timezone. * * @param dateValue the date value * @return the date */ public static Date convertDateValueToDate(long dateValue) { long millis = getMillis(null, yearFromDateValue(dateValue), monthFromDateValue(dateValue), dayFromDateValue(dateValue), 0, 0, 0, 0); return new Date(millis); } /** * Convert an encoded date value to millis, using the supplied timezone. * * @param tz the timezone * @param dateValue the date value * @return the date */ public static long convertDateValueToMillis(TimeZone tz, long dateValue) { return getMillis(tz, yearFromDateValue(dateValue), monthFromDateValue(dateValue), dayFromDateValue(dateValue), 0, 0, 0, 0); } /** * Convert an encoded date value / time value to a timestamp, using the * default timezone. * * @param dateValue the date value * @param timeNanos the nanoseconds since midnight * @return the timestamp */ public static Timestamp convertDateValueToTimestamp(long dateValue, long timeNanos) { long millis = timeNanos / 1000000; timeNanos -= millis * 1000000; long s = millis / 1000; millis -= s * 1000; long m = s / 60; s -= m * 60; long h = m / 60; m -= h * 60; long ms = getMillis(null, yearFromDateValue(dateValue), monthFromDateValue(dateValue), dayFromDateValue(dateValue), (int) h, (int) m, (int) s, 0); Timestamp ts = new Timestamp(ms); ts.setNanos((int) (timeNanos + millis * 1000000)); return ts; } /** * Convert a time value to a time, using the default timezone. * * @param nanosSinceMidnight the nanoseconds since midnight * @return the time */ public static Time convertNanoToTime(long nanosSinceMidnight) { long millis = nanosSinceMidnight / 1000000; long s = millis / 1000; millis -= s * 1000; long m = s / 60; s -= m * 60; long h = m / 60; m -= h * 60; long ms = getMillis(null, 1970, 1, 1, (int) (h % 24), (int) m, (int) s, (int) millis); return new Time(ms); } /** * Get the year from a date value. * * @param x the date value * @return the year */ public static int yearFromDateValue(long x) { return (int) (x >>> SHIFT_YEAR); } /** * Get the month from a date value. * * @param x the date value * @return the month (1..12) */ public static int monthFromDateValue(long x) { return (int) (x >>> SHIFT_MONTH) & 15; } /** * Get the day of month from a date value. * * @param x the date value * @return the day (1..31) */ public static int dayFromDateValue(long x) { return (int) (x & 31); } /** * Get the date value from a given date. * * @param year the year * @param month the month (1..12) * @param day the day (1..31) * @return the date value */ public static long dateValue(long year, int month, int day) { return (year << SHIFT_YEAR) | (month << SHIFT_MONTH) | day; } /** * Convert a UTC datetime in millis to an encoded date in the default * timezone. * * @param ms the milliseconds * @return the date value */ public static long dateValueFromDate(long ms) { Calendar cal = getCalendar(); cal.setTimeInMillis(ms); return dateValueFromCalendar(cal); } /** * Calculate the encoded date value from a given calendar. * * @param cal the calendar * @return the date value */ private static long dateValueFromCalendar(Calendar cal) { int year, month, day; year = getYear(cal); month = cal.get(Calendar.MONTH) + 1; day = cal.get(Calendar.DAY_OF_MONTH); return ((long) year << SHIFT_YEAR) | (month << SHIFT_MONTH) | day; } /** * Convert a time in milliseconds in UTC to the nanoseconds since midnight * (in the default timezone). * * @param ms the milliseconds * @return the nanoseconds */ public static long nanosFromDate(long ms) { Calendar cal = getCalendar(); cal.setTimeInMillis(ms); return nanosFromCalendar(cal); } /** * Convert a java.util.Calendar to nanoseconds since midnight. * * @param cal the calendar * @return the nanoseconds */ private static long nanosFromCalendar(Calendar cal) { int h = cal.get(Calendar.HOUR_OF_DAY); int m = cal.get(Calendar.MINUTE); int s = cal.get(Calendar.SECOND); int millis = cal.get(Calendar.MILLISECOND); return ((((((h * 60L) + m) * 60) + s) * 1000) + millis) * 1000000; } /** * Calculate the normalized timestamp. * * @param absoluteDay the absolute day * @param nanos the nanoseconds (may be negative or larger than one day) * @return the timestamp */ public static ValueTimestamp normalizeTimestamp(long absoluteDay, long nanos) { if (nanos > NANOS_PER_DAY || nanos < 0) { long d; if (nanos > NANOS_PER_DAY) { d = nanos / NANOS_PER_DAY; } else { d = (nanos - NANOS_PER_DAY + 1) / NANOS_PER_DAY; } nanos -= d * NANOS_PER_DAY; absoluteDay += d; } return ValueTimestamp.fromDateValueAndNanos( dateValueFromAbsoluteDay(absoluteDay), nanos); } /** * Calculate the absolute day from an encoded date value. * * @param dateValue the date value * @return the absolute day */ public static long absoluteDayFromDateValue(long dateValue) { long y = yearFromDateValue(dateValue); int m = monthFromDateValue(dateValue); int d = dayFromDateValue(dateValue); if (m <= 2) { y--; m += 12; } long a = ((y * 2922L) >> 3) + DAYS_OFFSET[m - 3] + d - 719484; if (y <= 1582 && ((y < 1582) || (m * 100 + d < 1005))) { // Julian calendar (cutover at 1582-10-04 / 1582-10-15) a += 13; } else if (y < 1901 || y > 2099) { // Gregorian calendar (slow mode) a += (y / 400) - (y / 100) + 15; } return a; } /** * Calculate the encoded date value from an absolute day. * * @param absoluteDay the absolute day * @return the date value */ public static long dateValueFromAbsoluteDay(long absoluteDay) { long d = absoluteDay + 719468; long y100 = 0, offset; if (d > 578040) { // Gregorian calendar long y400 = d / 146097; d -= y400 * 146097; y100 = d / 36524; d -= y100 * 36524; offset = y400 * 400 + y100 * 100; } else { // Julian calendar d += 292200000002L; offset = -800000000; } long y4 = d / 1461; d -= y4 * 1461; long y = d / 365; d -= y * 365; if (d == 0 && (y == 4 || y100 == 4)) { y--; d += 365; } y += offset + y4 * 4; // month of a day int m = ((int) d * 2 + 1) * 5 / 306; d -= DAYS_OFFSET[m] - 1; if (m >= 10) { y++; m -= 12; } return dateValue(y, m + 3, (int) d); } /** * Adds the number of months to the date. If the resulting month's number of * days is less than the original's day-of-month, the resulting * day-of-months gets adjusted accordingly:
* 30.04.2007 - 2 months = 28.02.2007 * * @param refDate the original date * @param nrOfMonthsToAdd the number of months to add * @return the new timestamp */ public static Timestamp addMonths(Timestamp refDate, int nrOfMonthsToAdd) { Calendar calendar = Calendar.getInstance(); calendar.setTime(refDate); calendar.add(Calendar.MONTH, nrOfMonthsToAdd); Timestamp resultDate = new Timestamp(calendar.getTimeInMillis()); resultDate.setNanos(refDate.getNanos()); return resultDate; } }





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