Java date and time operations

Package COM. netcode. date; import Java. text. dateformat; import Java. text. parseexception; import Java. text. simpledateformat; import Java. util. calendar; import Java. util. date; import Java. util. gregoriancalendar; import Java. util. timezone;/*** convert date and string types */public class dateutil {/*** base ISO 8601 Date Format yyyymmdd I. E ., 20021225 for the 25th day of December in the year 2002 */public static final string iso_date_format = "yyyymmdd";/*** expanded ISO 8601 Date Format yyyy-mm-dd I. E ., 2002-12-25 for the 25th day of December in the year 2002 */public static final string iso_expanded_date_format = "yyyy-mm-dd";/*** yyyy-mm-dd hh: mm: SS */public static string datetime_pattern = "yyyy-mm-dd hh: mm: SS";/*** default lenient setting for getdate. */Private Static Boolean lenient_date = false;/*** temporarily do not use * @ Param JD * @ return */protected static final float normalizedjulian (float JD) {float F = math. round (JD + 0.5f)-0.5f; return F;}/*** convert a floating point value to a date format <br> * do not use * returns the date from a Julian. the Julian date will be converted to noon GMT, * such that it matches the nearest half-INTEGER (I. E ., A Julian Date of 1.4 gets * changed to 1.5, and 0.9 gets changed to 0.5 .) ** @ Param JD the Julian Date * @ return the Gregorian date */public static final date todate (float JD) {/* to convert a Julian day number to a Gregorian date, assume that it is for 0 hours and Greenwich time (so * that it ends in 0.5 ). do the following calculations, again dropping the fractional part of all * multiplicatons and divisions. note: This method will not give dates accurately on the * Gregorian prow.tic calendar, I. E ., the calendar you get by extending the Gregorian * Calendar backwards to years earlier than 1582. using the Gregorian leap year * rules. in particle, the method fails if y <400. */float z = (normalizedjulian (JD) + 0.5f; float W = (INT) (Z-1867216.25f)/36524.25f); float x = (INT) (W/4f); float a = z + 1 + w-X; float B = a + 1524; float c = (INT) (B-122.1)/365.25 ); float d = (INT) (365.25f * C); float E = (INT) (B-d)/30.6001); float F = (INT) (30.6001f * E ); int day = (INT) (B-d-f); int month = (INT) (e-1); If (month> 12) {month = month-12 ;} int year = (INT) (C-4715); // (if month is January or February) or C-4716 (otherwise) if (month> 2) {year --;} calendar c = calendar. getinstance (); C. set (calendar. year, year); C. set (calendar. month, month-1); // damn 0 offsets C. set (calendar. date, day); Return C. gettime ();}/*** returns the days between two dates. positive values indicate that * The second date is after the first, and negative values indicate, well, * the opposite. relying on specific times is problematic. ** @ Param early the "First Date" * @ Param late the "second date" * @ return the days between the two dates */public static final int daysbetween (date early, date late) {calendar C1 = calendar. getinstance (); Calendar C2 = calendar. getinstance (); c1.settime (early); c2.settime (late); Return daysbetween (C1, C2);}/*** returns the days between two dates. positive values indicate that * The second date is after the first, and negative values indicate, well, * the opposite. ** @ Param early * @ Param late * @ return the days between two dates. */public static final int daysbetween (calendar early, calendar late) {return (INT) (tojulian (late)-tojulian (early ));} /*** return a Julian Date based on the input parameter. this is * based from calculations found at * <a href = "http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html"> Julian day calculations * (Gregorian calendar) </a>, provided by Bill jeffrys. * @ Param c a calendar instance * @ return the Julian day number */public static final float tojulian (calendar c) {int y = C. get (calendar. year); int M = C. get (calendar. month); int d = C. get (calendar. date); int A = y/100; int B = A/4; int c = 2-A + B; float E = (INT) (365.25f * (Y + 4716); float F = (INT) (30.6001f * (m + 1); float JD = C + D + E + F-1524.5f; return JD;}/*** not required for the moment * return a Julian Date based on the input parameter. this is * based from calculations found at * <a href = "http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html"> Julian day calculations * (Gregorian calendar) </a>, provided by Bill jeffrys. * @ Param date * @ return the Julian day number */public static final float tojulian (date) {calendar c = calendar. getinstance (); C. settime (date); Return tojulian (c);}/*** date added * @ Param isostring date string * @ Param FMT Format * @ Param field year/month/day calendar ar. year/calendar. month/calendar. date * @ Param amount increase quantity * @ return * @ throws parseexception */public static final string dateincrease (string isostring, string FMT, int field, int amount) {try {calendar Cal = gregoriancalendar. getinstance (timezone. gettimezone ("GMT"); Cal. settime (stringtodate (isostring, FMT, true); Cal. add (field, amount); Return datetostring (Cal. gettime (), FMT);} catch (exception ex) {return NULL ;}/ *** time field rolling function. * rolls (up/down) a single unit of time on the given time field. ** @ Param isostring * @ Param field the time field. * @ Param Up indicates if rolling up or rolling down the field value. * @ Param expanded use formating Char's * @ exception parseexception if an unknown field value is given. */public static final string roll (string isostring, string FMT, int field, Boolean up) throws parseexception {calendar Cal = gregoriancalendar. getinstance (timezone. gettimezone ("GMT"); Cal. settime (stringtodate (isostring, FMT); Cal. roll (field, up); Return datetostring (Cal. gettime (), FMT);}/*** time field rolling function. * rolls (up/down) a single unit of time on the given time field. ** @ Param isostring * @ Param field the time field. * @ Param Up indicates if rolling up or rolling down the field value. * @ exception parseexception if an unknown field value is given. */public static final string roll (string isostring, int field, Boolean up) throws parseexception {return roll (isostring, datetime_pattern, field, up );} /*** convert string to date Java. util. date * @ Param datetext string * @ Param Format date format * @ Param lenient date out-of-bounds mark * @ return */public static date stringtodate (string datetext, string format, Boolean lenient) {If (datetext = NULL) {return NULL;} dateformat df = NULL; try {If (format = NULL) {df = new simpledateformat ();} else {df = new simpledateformat (format);} // setlenient avoids allowing dates like 9/32/2001 // which wowould otherwise parse to 10/2/2001 DF. setlenient (false); Return DF. parse (datetext);} catch (parseexception e) {return NULL ;}/ *** string to date Java. util. date * @ Param datetext string * @ Param Format date format * @ return */public static date stringtodate (string datestring, string format) {return stringtodate (datestring, format, lenient_date );} /*** convert string to date Java. util. date * @ Param datetext string */public static date stringtodate (string datestring) {return stringtodate (datestring, iso_expanded_date_format, lenient_date );} /** return a time string based on the time variable * @ return a time string * @ Param pattern time string style * @ Param date time variable */public static string datetostring (date, string Pattern) {If (date = NULL) {return NULL;} Try {simpledateformat sfdate = new simpledateformat (pattern); sfdate. setlenient (false); Return sfdate. format (date) ;}catch (exception e) {return NULL ;}} /*** return the time string yyyy-mm-dd * @ Param date * @ return */public static string datetostring (date) {return datetostring (date, iso_expanded_date_format);}/** returns the current time * @ return returns the current time */public static date getcurrentdatetime () {Java. util. calendar calnow = Java. util. calendar. getinstance (); Java. util. date dtnow = calnow. gettime (); Return dtnow;}/*** returns the current date string * @ Param pattern date string style * @ return */public static string getcurrentdatestring (string pattern) {return datetostring (getcurrentdatetime (), pattern);}/*** returns the current date string yyyy-mm-dd * @ return */public static string getcurrentdatestring () {return datetostring (getcurrentdatetime (), iso_expanded_date_format);}/*** returns the current date + time string yyyy-mm-dd hh: mm: SS * @ Param date * @ return */public static string datetostringwithtime (date) {return datetostring (date, datetime_pattern );} /*** date increase-add * @ Param date * @ Param days * @ return Java. util. date */public static date dateincreasebyday (date, int days) {calendar Cal = gregoriancalendar. getinstance (timezone. gettimezone ("GMT"); Cal. settime (date); Cal. add (calendar. date, days); Return Cal. gettime ();}/*** date increase-monthly increase * @ Param date * @ Param days * @ return Java. util. date */public static date dateincreasebymonth (date, int MNT) {calendar Cal = gregoriancalendar. getinstance (timezone. gettimezone ("GMT"); Cal. settime (date); Cal. add (calendar. month, MNT); Return Cal. gettime ();}/*** date increase-add by year * @ Param date * @ Param MNT * @ return Java. util. date */public static date dateincreasebyyear (date, int MNT) {calendar Cal = gregoriancalendar. getinstance (timezone. gettimezone ("GMT"); Cal. settime (date); Cal. add (calendar. year, MNT); Return Cal. gettime ();} /*** add date * @ Param date string yyyy-mm-dd * @ Param days * @ return date string yyyy-mm-dd */public static string dateincreasebyday (string date, int days) {return dateincreasebyday (date, iso_date_format, days );} /*** add date * @ Param date string * @ Param FMT date format * @ Param days * @ return */public static string dateincreasebyday (string date, string FMT, int days) {return dateincrease (date, FMT, calendar. date, days );} /*** convert the date string format ** @ Param SRC date string * @ Param srcfmt source date format * @ Param desfmt target date format * @ return */public static string stringtostring (string SRC, string srcfmt, string desfmt) {return datetostring (stringtodate (SRC, srcfmt), desfmt );}}