I'm trying to implement without success a Date iterator with Joda time.
I need something that allows me to iterate all the days form startDate to endDate
Do you have any idea on how to do that?
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2This help at all? stackoverflow.com/questions/847520/…Davis– Davis2009-07-23 22:48:36 +00:00Commented Jul 23, 2009 at 22:48
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2If you want days, you want to look at the LocalDate class (set one as your start date) and do a plus days for each next. This will avoid the timezone issues inherent in instant.Yishai– Yishai2009-07-23 23:37:00 +00:00Commented Jul 23, 2009 at 23:37
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3 Answers
Here's something to get you started. You may want to think about whether you want it to be inclusive or exclusive at the end, etc.
import org.joda.time.*;
import java.util.*;
class LocalDateRange implements Iterable<LocalDate>
{
private final LocalDate start;
private final LocalDate end;
public LocalDateRange(LocalDate start,
LocalDate end)
{
this.start = start;
this.end = end;
}
public Iterator<LocalDate> iterator()
{
return new LocalDateRangeIterator(start, end);
}
private static class LocalDateRangeIterator implements Iterator<LocalDate>
{
private LocalDate current;
private final LocalDate end;
private LocalDateRangeIterator(LocalDate start,
LocalDate end)
{
this.current = start;
this.end = end;
}
public boolean hasNext()
{
return current != null;
}
public LocalDate next()
{
if (current == null)
{
throw new NoSuchElementException();
}
LocalDate ret = current;
current = current.plusDays(1);
if (current.compareTo(end) > 0)
{
current = null;
}
return ret;
}
public void remove()
{
throw new UnsupportedOperationException();
}
}
}
class Test
{
public static void main(String args[])
{
LocalDate start = new LocalDate(2009, 7, 20);
LocalDate end = new LocalDate(2009, 8, 3);
for (LocalDate date : new LocalDateRange(start, end))
{
System.out.println(date);
}
}
}
It's a while since I've written an iterator in Java, so I hope it's right. I think it's pretty much okay...
Oh for C# iterator blocks, that's all I can say...
3 Comments
Lotus Notes
Thank you, this just made my life at least 900% easier.
Jonik
I was googling for whether Joda has something to represent a "date range"... Apparently not, since you propose writing one's own LocalDateRange.
Stephan
@Jonik Joda offers the Interval interface and its various implementation. However I was not able to find an
Iterable implementation: maybe more complex...
Comments
I know you asked about Joda-Time. Today we should prefer to use java.time, the modern Java date and time API that is basically a further development of Joda-Time. Since Java 9 the iteration of a date range has been built in through a Stream:
LocalDate startDate = LocalDate.of(2019, Month.AUGUST, 28);
LocalDate endate = LocalDate.of(2019, Month.SEPTEMBER, 3);
startDate.datesUntil(endate).forEach(System.out::println);
Output:
2019-08-28 2019-08-29 2019-08-30 2019-08-31 2019-09-01 2019-09-02
If you wanted the end date to be inclusive, use datesUntil(endate.plusDays(1)).
And if you literally wanted an Iterator:
Iterator<LocalDate> ldi = startDate.datesUntil(endate).iterator();
The Joda-Time home page says:
Note that Joda-Time is considered to be a largely “finished” project. No major enhancements are planned. If using Java SE 8, please migrate to
java.time(JSR-310).
