Apple

Hi,

I have modelled calendar entries, which have a timestamp attribute. I wanted to build a qualifier that matches all entries within a month so I created start and end timestamps programatically. The start timestamp is no problem. To get the end timestamp, I used NSTimestamp.timestampByAddingGregorianUnits and added "a month minus one second". This works fine for GMT, but gives me funky results for e.g. Europe/Berlin. Please see code and output below. Any ideas? This is with WO 5.3.3.

Timo

Hi Timo,

you might also try the joda-time library. It has functions for using the "natural" meaning of intervals like "1 month".

...

NSTimestamp start = new NSTimestamp(year, month, 1, 0, 0, 0, timezone);

DateTimeZone dtz = DateTimeZone.forTimeZone(timezone);

DateTime ydt = new DateTime(start, dtz);

NSTimestamp end = new NSTimestamp(ydt.plusMonths(1).minusSeconds(1).toDate());

...

2008-01-01 00:00:00 Etc/GMT -> 2008-01-31 23:59:59 Etc/GMT

2008-02-01 00:00:00 Etc/GMT -> 2008-02-29 23:59:59 Etc/GMT

2008-03-01 00:00:00 Etc/GMT -> 2008-03-31 23:59:59 Etc/GMT

2008-04-01 00:00:00 Etc/GMT -> 2008-04-30 23:59:59 Etc/GMT

2008-05-01 00:00:00 Etc/GMT -> 2008-05-31 23:59:59 Etc/GMT

2008-06-01 00:00:00 Etc/GMT -> 2008-06-30 23:59:59 Etc/GMT

2008-07-01 00:00:00 Etc/GMT -> 2008-07-31 23:59:59 Etc/GMT

2008-08-01 00:00:00 Etc/GMT -> 2008-08-31 23:59:59 Etc/GMT

2008-09-01 00:00:00 Etc/GMT -> 2008-09-30 23:59:59 Etc/GMT

2008-10-01 00:00:00 Etc/GMT -> 2008-10-31 23:59:59 Etc/GMT

2008-11-01 00:00:00 Etc/GMT -> 2008-11-30 23:59:59 Etc/GMT

2008-12-01 00:00:00 Etc/GMT -> 2008-12-31 23:59:59 Etc/GMT

2008-01-01 00:00:00 Europe/Berlin -> 2008-01-31 23:59:59 Europe/Berlin

2008-02-01 00:00:00 Europe/Berlin -> 2008-02-29 23:59:59 Europe/Berlin

2008-03-01 00:00:00 Europe/Berlin -> 2008-03-31 23:59:59 Europe/Berlin

2008-04-01 00:00:00 Europe/Berlin -> 2008-04-30 23:59:59 Europe/Berlin

2008-05-01 00:00:00 Europe/Berlin -> 2008-05-31 23:59:59 Europe/Berlin

2008-06-01 00:00:00 Europe/Berlin -> 2008-06-30 23:59:59 Europe/Berlin

2008-07-01 00:00:00 Europe/Berlin -> 2008-07-31 23:59:59 Europe/Berlin

2008-08-01 00:00:00 Europe/Berlin -> 2008-08-31 23:59:59 Europe/Berlin

2008-09-01 00:00:00 Europe/Berlin -> 2008-09-30 23:59:59 Europe/Berlin

2008-10-01 00:00:00 Europe/Berlin -> 2008-10-31 23:59:59 Europe/Berlin

2008-11-01 00:00:00 Europe/Berlin -> 2008-11-30 23:59:59 Europe/Berlin

2008-12-01 00:00:00 Europe/Berlin -> 2008-12-31 23:59:59 Europe/Berlin

Ralf

public class NSTimestampTest {
public static void main(String[] args) {
int year = 2008;

// This one works
NSTimeZone gmt = NSTimeZone.getGMT();
test(gmt, year);

// This one doesn't
NSTimeZone berlin = NSTimeZone.timeZoneWithName("Europe/Berlin", false);
test(berlin, year);
}

private static void test(NSTimeZone timezone, int year) {
NSTimestampFormatter formatter = new NSTimestampFormatter("%Y-%m-%d %H:%M:%S %Z");
formatter.setDefaultFormatTimeZone(timezone);

for (int month = 1; month <= 12; month++) {
NSTimestamp start = new NSTimestamp(year, month, 1, 0, 0, 0, timezone);
NSTimestamp end = start.timestampByAddingGregorianUnits(0, 1, 0, 0, 0, -1);
System.out.printf("%s -> %s\n", formatter.format(start), formatter.format(end));
}
}
}

results in

2008-01-01 00:00:00 Etc/GMT -> 2008-01-31 23:59:59 Etc/GMT
2008-02-01 00:00:00 Etc/GMT -> 2008-02-29 23:59:59 Etc/GMT
2008-03-01 00:00:00 Etc/GMT -> 2008-03-31 23:59:59 Etc/GMT
2008-04-01 00:00:00 Etc/GMT -> 2008-04-30 23:59:59 Etc/GMT
2008-05-01 00:00:00 Etc/GMT -> 2008-05-31 23:59:59 Etc/GMT
2008-06-01 00:00:00 Etc/GMT -> 2008-06-30 23:59:59 Etc/GMT
2008-07-01 00:00:00 Etc/GMT -> 2008-07-31 23:59:59 Etc/GMT
2008-08-01 00:00:00 Etc/GMT -> 2008-08-31 23:59:59 Etc/GMT
2008-09-01 00:00:00 Etc/GMT -> 2008-09-30 23:59:59 Etc/GMT
2008-10-01 00:00:00 Etc/GMT -> 2008-10-31 23:59:59 Etc/GMT
2008-11-01 00:00:00 Etc/GMT -> 2008-11-30 23:59:59 Etc/GMT
2008-12-01 00:00:00 Etc/GMT -> 2008-12-31 23:59:59 Etc/GMT
2008-01-01 00:00:00 Europe/Berlin -> 2008-01-31 23:59:59 Europe/Berlin
2008-02-01 00:00:00 Europe/Berlin -> 2008-02-29 23:59:59 Europe/Berlin
2008-03-01 00:00:00 Europe/Berlin -> 2008-03-29 23:59:59 Europe/Berlin
2008-04-01 00:00:00 Europe/Berlin -> 2008-04-30 23:59:59 Europe/Berlin
2008-05-01 00:00:00 Europe/Berlin -> 2008-05-30 23:59:59 Europe/Berlin
2008-06-01 00:00:00 Europe/Berlin -> 2008-06-30 23:59:59 Europe/Berlin
2008-07-01 00:00:00 Europe/Berlin -> 2008-07-30 23:59:59 Europe/Berlin
2008-08-01 00:00:00 Europe/Berlin -> 2008-08-31 23:59:59 Europe/Berlin
2008-09-01 00:00:00 Europe/Berlin -> 2008-09-30 23:59:59 Europe/Berlin
2008-10-01 00:00:00 Europe/Berlin -> 2008-10-30 22:59:59 Europe/Berlin
2008-11-01 00:00:00 Europe/Berlin -> 2008-11-30 23:59:59 Europe/Berlin
2008-12-01 00:00:00 Europe/Berlin -> 2008-12-30 23:59:59 Europe/Berlin

References:
	>NSTimestamp.timestampByAddingGregorianUnits considered harmful (From: Timo Hoepfner <email@hidden>)