From: http://www.jguru.com/forums/view.jsp?EID=489372 - * - * @return the number of days between d1 and d2, 0 if they are the - * same day. + * @deprecated Use {@link Calendars#getDaysBetween}. */ public static int getDaysBetween (Calendar d1, Calendar d2) { - if (d1.after(d2)) { // swap dates so that d1 is start and d2 is end - Calendar swap = d1; - d1 = d2; - d2 = swap; - } - - int days = d2.get(Calendar.DAY_OF_YEAR) - d1.get(Calendar.DAY_OF_YEAR); - int y2 = d2.get(Calendar.YEAR); - if (d1.get(Calendar.YEAR) != y2) { - d1 = (Calendar)d1.clone(); - do { - days += d1.getActualMaximum(Calendar.DAY_OF_YEAR); - d1.add(Calendar.YEAR, 1); - } while (d1.get(Calendar.YEAR) != y2); - } - return days; + return Calendars.getDaysBetween(d1, d2); } /** - * Returns the number of whole months between the dates represented by the - * two calendar objects, truncating any remainder. The order of the two - * dates in time does not matter, the absolute number of months between - * them will be returned. + * @deprecated Use {@link Calendars#getMonthsBetween}. */ public static int getMonthsBetween (Calendar start, Calendar end) { - if (end.before(start)) { - Calendar swap = start; - start = end; - end = swap; - } - - // we're going to manipulate end, so let's clone it - end = (Calendar)end.clone(); - - int months = -1; - do { - end.add(Calendar.MONTH, -1); - months++; - } while (!start.after(end)); - - return months; + return Calendars.getMonthsBetween(start, end); } } diff --git a/src/java/com/samskivert/util/Calendars.java b/src/java/com/samskivert/util/Calendars.java new file mode 100644 index 00000000..f44087de --- /dev/null +++ b/src/java/com/samskivert/util/Calendars.java @@ -0,0 +1,285 @@ +// +// $Id$ +// +// samskivert library - useful routines for java programs +// Copyright (C) 2001-2008 Michael Bayne +// +// This library is free software; you can redistribute it and/or modify it +// under the terms of the GNU Lesser General Public License as published +// by the Free Software Foundation; either version 2.1 of the License, or +// (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public +// License along with this library; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +package com.samskivert.util; + +import java.sql.Timestamp; +import java.util.Calendar; +import java.util.Date; +import java.util.Locale; +import java.util.TimeZone; + +/** + * A fluent approach to dealing with {@link Calendar} and some calendar related utilities. + * Instead of: + *
+ * Calendar cal = Calendar.getInstance(); + * cal.set(Calendar.HOUR_OF_DAY, 0); + * cal.set(Calendar.MINUTE, 0); + * cal.set(Calendar.SECOND, 0); + * cal.set(Calendar.MILLISECOND, 0); + * cal.add(Calendar.DATE, 1); + * long nextMidnight = cal.getTimeInMillis(); + *+ * you can simply write: + *
+ * long nextMidnight = Calendars.now().zeroTime().addDay(1).toTime(); + *+ */ +public class Calendars +{ + /** Provides fluent methods for operating on a {@link Calendar}. */ + public static class Builder + { + /** Sets the {@link Calendar#YEAR} field to the specified value. */ + public Builder setYear (int year) { + return set(Calendar.YEAR, year); + } + + /** Adds the specified value to the {@link Calendar#YEAR} field. Use negative values to + * subtract. */ + public Builder addYears (int years) { + return add(Calendar.YEAR, years); + } + + /** Sets the {@link Calendar#MONTH} field to the specified value. Use {@link + * Calendar#JANUARY} and friends or rue your foolishness. */ + public Builder setMonth (int month) { + return set(Calendar.MONTH, month); + } + + /** Adds the specified value to the {@link Calendar#MONTH} field. Use negative values to + * subtract. */ + public Builder addMonths (int months) { + return add(Calendar.MONTH, months); + } + + /** Sets the {@link Calendar#DATE} field to the specified value. The first day of the month + * has value 1. */ + public Builder setDay (int day) { + return set(Calendar.DATE, day); + } + + /** Adds the specified value to the {@link Calendar#DATE} field. Use negative values to + * subtract. */ + public Builder addDays (int days) { + return add(Calendar.DATE, days); + } + + /** Sets the {@link Calendar#HOUR_OF_DAY} field to the specified value. This uses a 24-hour + * clock. Midnight is 0. */ + public Builder setHour (int hour) { + return set(Calendar.HOUR_OF_DAY, hour); + } + + /** Adds the specified value to the {@link Calendar#HOUR_OF_DAY} field. Use negative values + * to subtract. */ + public Builder addHours (int hours) { + return add(Calendar.HOUR_OF_DAY, hours); + } + + /** Sets the {@link Calendar#MINUTE} field to the specified value. */ + public Builder setMinute (int minute) { + return set(Calendar.MINUTE, minute); + } + + /** Adds the specified value to the {@link Calendar#MINUTE} field. Use negative values to + * subtract. */ + public Builder addMinutes (int minutes) { + return add(Calendar.MINUTE, minutes); + } + + /** See {@link Calendar#add}. */ + public Builder add (int field, int amount) { + _calendar.add(field, amount); + return this; + } + + /** See {@link Calendar#roll}. */ + public Builder roll (int field, boolean up) { + _calendar.roll(field, up); + return this; + } + + /** See {@link Calendar#set(int,int)}. */ + public Builder set (int field, int value) { + _calendar.set(field, value); + return this; + } + + /** Zeros out the time fields of this calendar, preserving only the date. */ + public Builder zeroTime () { + _calendar.set(Calendar.HOUR_OF_DAY, 0); + _calendar.set(Calendar.MINUTE, 0); + _calendar.set(Calendar.SECOND, 0); + _calendar.set(Calendar.MILLISECOND, 0); + return this; + } + + /** Returns the milliseconds since the epoch for our calendar's current time. */ + public long toTime () { + return _calendar.getTimeInMillis(); + } + + /** Returns a {@link Date} configured with our calendar's current time. */ + public Date toDate () { + return _calendar.getTime(); + } + + /** Returns a {@link java.sql.Date} configured with our calendar's current time. */ + public java.sql.Date toSQLDate () { + return new java.sql.Date(toTime()); + } + + /** Returns a {@link java.sql.Timestamp} configured with our calendar's current time. */ + public Timestamp toTimestamp () { + return new Timestamp(toTime()); + } + + /** See {@link Calendar#get}. */ + public int get (int field) { + return _calendar.get(field); + } + + /** Returns the wrapped {@link Calendar} instance. Note: modifications to the + * returned calendar will also affect this instance. */ + public Calendar asCalendar () { + return _calendar; + } + + protected Builder (Calendar calendar) { + _calendar = calendar; + } + + protected final Calendar _calendar; + } + + /** + * Returns a fluent wrapper around the supplied calendar. + */ + public static Builder with (Calendar calendar) + { + return new Builder(calendar); + } + + /** + * Returns a fluent wrapper around a calendar obtained with {@link Calendar#getInstance}. + */ + public static Builder now () + { + return with(Calendar.getInstance()); + } + + /** + * Returns a fluent wrapper around a calendar configured with the specified time. + */ + public static Builder at (long millis) + { + Calendar calendar = Calendar.getInstance(); + calendar.setTimeInMillis(millis); + return with(calendar); + } + + /** + * Returns a fluent wrapper around a calendar configured with the specified time. + */ + public static Builder at (Date when) + { + return at(when.getTime()); + } + + /** + * Returns a fluent wrapper around a calendar for the specifed time zone. + */ + public static Builder in (TimeZone zone) + { + return with(Calendar.getInstance(zone)); + } + + /** + * Returns a fluent wrapper around a calendar for the specifed locale. + */ + public static Builder in (Locale locale) + { + return with(Calendar.getInstance(locale)); + } + + /** + * Returns a fluent wrapper around a calendar for the specifed time zone and locale. + */ + public static Builder in (TimeZone zone, Locale locale) + { + return with(Calendar.getInstance(zone, locale)); + } + + /** + * Returns the difference between the dates represented by the two calendars in days, properly + * accounting for daylight savings time, leap seconds, etc. The order of the two dates in time + * does not matter, the absolute number of days between them will be returned. + * + *
From: http://www.jguru.com/forums/view.jsp?EID=489372 + * + * @return the number of days between d1 and d2, 0 if they are the same day. + */ + public static int getDaysBetween (Calendar d1, Calendar d2) + { + if (d1.after(d2)) { // swap dates so that d1 is start and d2 is end + Calendar swap = d1; + d1 = d2; + d2 = swap; + } + + int days = d2.get(Calendar.DAY_OF_YEAR) - d1.get(Calendar.DAY_OF_YEAR); + int y2 = d2.get(Calendar.YEAR); + if (d1.get(Calendar.YEAR) != y2) { + d1 = (Calendar)d1.clone(); + do { + days += d1.getActualMaximum(Calendar.DAY_OF_YEAR); + d1.add(Calendar.YEAR, 1); + } while (d1.get(Calendar.YEAR) != y2); + } + return days; + } + + /** + * Returns the number of whole months between the dates represented by the two calendar + * objects, truncating any remainder. The order of the two dates in time does not matter, the + * absolute number of months between them will be returned. + */ + public static int getMonthsBetween (Calendar start, Calendar end) + { + if (end.before(start)) { + Calendar swap = start; + start = end; + end = swap; + } + + // we're going to manipulate end, so let's clone it + end = (Calendar)end.clone(); + + int months = -1; + do { + end.add(Calendar.MONTH, -1); + months++; + } while (!start.after(end)); + + return months; + } +}