diff src/fschmidt/util/java/DateUtils.java @ 68:00520880ad02

add fschmidt source
author Franklin Schmidt <fschmidt@gmail.com>
date Sun, 05 Oct 2025 17:24:15 -0600
parents
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fschmidt/util/java/DateUtils.java	Sun Oct 05 17:24:15 2025 -0600
@@ -0,0 +1,97 @@
+/*
+Copyright (c) 2008  Franklin Schmidt <fschmidt@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package fschmidt.util.java;
+
+import java.util.Calendar;
+import java.util.Date;
+
+
+public class DateUtils {
+	private DateUtils() {}  // never
+
+	public static Date roundToDay(Date date) {
+		Calendar cal = Calendar.getInstance();
+		cal.setLenient(false);
+		cal.setTime(date);
+		Calendar cal2 = Calendar.getInstance();
+		cal2.setLenient(false);
+		cal2.clear();
+		cal2.set(cal.get(Calendar.YEAR),cal.get(Calendar.MONTH),cal.get(Calendar.DATE));
+		return cal2.getTime();
+	}
+
+	public static Date add(Date date,int days,int unit) {
+		Calendar cal = Calendar.getInstance();
+		cal.setLenient(false);
+		cal.setTime(date);
+		cal.add(unit,days);
+		return cal.getTime();
+	}
+
+	public static Date addDays(Date date,int days) {
+		return add(date,days,Calendar.DATE);
+	}
+
+	public static Date addHours(Date date,int hours) {
+		return add(date,hours,Calendar.HOUR);
+	}
+
+	private static final long millisPerHour = 1000L*60L*60L;
+	private static final long millisPerDay = millisPerHour*24L;
+	
+	public static int daysBetween(Date dateFrom,Date dateTo) {
+		long from = dateFrom.getTime();
+		long to = dateTo.getTime();
+		long diff = (to - from)/millisPerDay;
+		return (int)diff;
+	}
+
+	public static int datesBetween(Date dateFrom,Date dateTo) {
+		long from = roundToDay(dateFrom).getTime();
+		long to = roundToDay(dateTo).getTime();
+		long diff = (to - from + millisPerHour)/millisPerDay;
+		return (int)diff;
+	}
+
+	public static Date max(Date date1,Date date2) {
+		return date1.after(date2) ? date1 : date2;
+	}
+
+	public static Date min(Date date1,Date date2) {
+		return date1.before(date2) ? date1 : date2;
+	}
+
+	public static boolean equalToTheSecond(Date date1,Date date2) {
+		return date1!=null && date2!=null && date1.getTime()/1000 == date2.getTime()/1000;
+	}
+
+
+	public static void main(String[] args) {
+		Date today = roundToDay(new Date());
+		Date date = today;
+		for( int i=0; i<10; i++ ) {
+			System.out.println(daysBetween(today,date));
+			date = addDays(date,1);
+		}
+	}
+}