Re: java.util.Calendar question

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 05 May 2010 19:37:56 -0400
Message-ID:
<hrsvgc$beh$1@news.albasani.net>
laredotornado wrote:

However, this loop is consistently returning a calendar instance that
is Saturday. Any ideas of something obvious that I'm missing here?


markspace wrote:

This worked for me:

<code>
public class CalendarTest {
   public static void main( String[] args )
   {
      Calendar c = Calendar.getInstance();
      System.err.println( Calendar.SUNDAY );
      System.err.println( c.get( Calendar.DAY_OF_WEEK ) );
      while( c.get( Calendar.DAY_OF_WEEK ) != Calendar.SUNDAY ) {
         c.roll( Calendar.DAY_OF_WEEK, -1 );
         System.err.println( c.get( Calendar.DAY_OF_WEEK ) );
         System.err.println( c.getTime() );
      }
   }
}
</code>
<output>
run:
1
4
3
Tue May 04 13:10:08 PDT 2010
2
Mon May 03 13:10:08 PDT 2010
1
Sun May 02 13:10:08 PDT 2010
BUILD SUCCESSFUL (total time: 1 second)
</output>


The problem there is the suspect definition of 'roll()':
"Adds the specified (signed) amount to the specified calendar field without
changing larger fields"

as opposed to 'add()', which reconciles the other fields.

--
Lew

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