File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Java in General and the fly likes Calendar roll() not working Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Java in General
Bookmark "Calendar roll() not working" Watch "Calendar roll() not working" New topic

Calendar roll() not working

Judy Herilla
Ranch Hand

Joined: Jan 05, 2001
Posts: 89
I am getting a Calendar representing today - March 1st, 2001 and rolling it back one day. I am not ending up with Feb 28th, but March 31st. This has worked in changing from January to Fevruary, but now I am having this problem. I read in the API that GregorianCalendar should resolve this issue, but I saw the same results - March 31st, 2001.
Any thoughts on how to fix this? Besides writing code to handle February?
GregorianCalendar newCal = new GregorianCalendar();
System.out.println("Todays calendar date:" + getStringFromCalendar(newCal));
//roll back the number of days between the dates passed in
newCal.roll(Calendar.DATE, -1);
System.out.println("After rollback New calendar date:" + getStringFromCalendar(newCal));

Manfred Leonhardt
Ranch Hand

Joined: Jan 09, 2001
Posts: 1492
Hi Johanna,
Try to use Calendar.DAY_OF_YEAR instead. It will work every time in the roll method.
NOTE: According to API: Calendar.DATE is equivalent to Calendar.DAY_OF_MONTH which makes sense with yours results!
[This message has been edited by Manfred Leonhardt (edited March 01, 2001).]
Judy Herilla
Ranch Hand

Joined: Jan 05, 2001
Posts: 89
Thanks Manfred, that did the trick!!!
I agree. Here's the link:
subject: Calendar roll() not working
It's not a secret anymore!