oms3.util.Times Maven / Gradle / Ivy
/*
* $Id:$
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source
* distribution.
*/
package oms3.util;
import java.util.Calendar;
/**
*
* @author Olaf David
*/
public class Times {
/** Solar year (Dec 21st - Dec20th). */
public static final int SOLAR_YEAR = 1;
/** Water year (Oct 1st - Sept 31st) */
public static final int WATER_YEAR = 2;
/** Calendar year (Jan 1st - Dec 31st) */
public static final int CALENDAR_YEAR = 3;
private static final long SERIAL_BASE_1900 = -2209050000000l;
/**
* All minutes have this many milliseconds except the last minute of the day on a day defined with
* a leap second.
*/
public static final long MILLISECS_PER_MINUTE = 60 * 1000;
/**
* Number of milliseconds per hour, except when a leap second is inserted.
*/
public static final long MILLISECS_PER_HOUR = 60 * MILLISECS_PER_MINUTE;
/**
* Number of leap seconds per day expect on
*
1. days when a leap second has been inserted, e.g. 1999 JAN 1.
*
2. Daylight-savings "spring forward" or "fall back" days.
*/
protected static final long MILLISECS_PER_DAY = 24 * MILLISECS_PER_HOUR;
/**
* Value to add to the day number returned by this calendar to find the Julian Day number.
* This is the Julian Day number for 1/1/1970.
* Note: Since the unix Day number is the same from local midnight to local midnight adding
* JULIAN_DAY_OFFSET to that value results in the chronologist, historians, or calenderists
* Julian Day number.
*/
public static final long EPOCH_UNIX_ERA_DAY = 2440588L;
/**
* @param cal
* @return Day number where day 0 is 1/1/1970, as per the Unix/Java date/time epoch.
*/
public static long getUnixDay(Calendar cal) {
long offset = cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET);
long day = (long) Math.floor((double) (cal.getTime().getTime() + offset) / ((double) MILLISECS_PER_DAY));
return day;
}
/**
* @return LOCAL Chronologists Julian day number each day starting from midnight LOCAL TIME.
*/
public static long getJulianDay(Calendar cal) {
return getUnixDay(cal) + EPOCH_UNIX_ERA_DAY;
}
/**
* find the number of days from this date to the given end date.
* later end dates result in positive values.
* Note this is not the same as subtracting day numbers. Just after midnight subtracted from just before
* midnight is 0 days for this method while subtracting day numbers would yields 1 day.
* @param end - any Calendar representing the moment of time at the end of the interval for calculation.
*/
public static long diffDayPeriods(Calendar start, Calendar end) {
long endL = end.getTimeInMillis() + end.getTimeZone().getOffset(end.getTimeInMillis());
long startL = start.getTimeInMillis() + start.getTimeZone().getOffset(start.getTimeInMillis());
return (endL - startL) / MILLISECS_PER_DAY;
}
/** Check if a year is a leap year.
*
* @param year the calendar year to check
* @return true is the given year is a leap year.
*/
public static boolean isLeapYear(int year) {
return year >= 1582 ? ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0))) : // Gregorian
(year % 4 == 0); // Julian
}
/** Get the Day of the year in WATER, SOLAR, or CALENDAR year.
*/
public static int getDayOfYear(Calendar cal, int type) {
int jday = cal.get(Calendar.DAY_OF_YEAR);
int mo = cal.get(java.util.Calendar.MONTH) + 1;
if (type == CALENDAR_YEAR) {
return jday;
} else if (type == SOLAR_YEAR) {
int day = cal.get(Calendar.DAY_OF_MONTH);
return (mo == 12 && day > 21) ? (day - 21) : (jday + 10);
} else if (type == WATER_YEAR) {
return (mo > 9) ? (jday - (isLeapYear(cal.get(Calendar.YEAR)) ? 274 : 273)) : (jday + 92);
}
throw new IllegalArgumentException("getDayOfYear() type argument unknown");
}
/**
* Convert a calendar to a serial date value. a serial date is the number
* of days since Jan 01 1900 plus a fractional.
* @param cal the calendar object
* @return the serial date
*/
public static double toSerialDate(Calendar cal) {
long calTime = cal.getTimeInMillis();
return (((double) (calTime - SERIAL_BASE_1900) / 86400000l) + 1.0);
}
/** Set a calendar object to a serial date value.
*
* @param cal the calendar to set the value
* @param serialDate the serial date to apply
*/
public static void setSerialDate(Calendar cal, double serialDate) {
cal.setTimeInMillis(SERIAL_BASE_1900 + (long) ((serialDate - 1.0) * 86400000l));
}
/** This used to be 'deltim' in MMS.
*/
public static double deltaHours(int calUnit, int increments) {
if (calUnit == Calendar.DATE) {
return 24 * increments;
} else if (calUnit == Calendar.HOUR) {
return increments;
} else if (calUnit == Calendar.MINUTE) {
return increments / 60;
} else if (calUnit == Calendar.SECOND) {
return increments / 3600;
}
return -1;
}
}