Help with date / calendar calculations.

**cg_news** · Jul 17 '05, 10:46 PM

Re: Help with date / calendar calculations.

cg_news wrote:
[color=blue]
> In short, what I am trying to do is, based on a date, calculate the week
> of year (as described in ISO 8601), then calculate the first and last date
> in this week period and return them in the format CCYYMMDD. Sounds easy
> enough, right??
>
> I am attempting to accomplish this by creating a GregorianCalend er which
> will get me the week of year. Then by changing the day of week to 1 (start
> of week) i'm trying the get the first day of the week, and day_of_week = 7
> should get me the last. Maybe?
>
> I think I may have successfully done this by using an instance of the
> GregorianCalend ar with the no argument constructor, which appears to
> default to the current system date/time. However, when I attempt to do the
> same with the GregorianCalend ar(int year, int month, int date)
> constructor, it does not work. It seems that my attemps to set the
> DAY_OF_WEEK value have no effect?
>
> Some code samples below,
> Thanks for any help you can offer...
> Carl.[/color]

Doh!
Code:
-start code--------------------------------------
import java.text.Field Position;
import java.text.Simpl eDateFormat;
import java.util.Grego rianCalendar;

public class WeekTest {

private GregorianCalend ar calendar;

public WeekTest(Gregor ianCalendar calendar) {
this.calendar = calendar;
this.calendar.s etFirstDayOfWee k(GregorianCale ndar.MONDAY);
this.calendar.s etMinimalDaysIn FirstWeek(4);
System.out.prin tln("\nStarting as: " +
calendar.getTim e().toString()) ;
}

public WeekTest(int year, int month, int date) {
this(new GregorianCalend ar(year, month, date, 1, 1));
}

public WeekTest() {
this(new GregorianCalend ar());
}

public String getWeek(){
String format = "yyyyww";
return doFormat(format , calendar);
}

public String getStartDate(){
calendar.set(Gr egorianCalendar .DAY_OF_WEEK,
GregorianCalend ar.MONDAY);
calendar.get(Gr egorianCalendar .MILLISECOND);
System.out.prin t("Week Start: " +
calendar.getTim e().toString() + " = ");

String format = "yyyyMMdd";
return doFormat(format , calendar);
}

public String getEndDate(){
calendar.set(Gr egorianCalendar .DAY_OF_WEEK,
GregorianCalend ar.SUNDAY);
System.out.prin t("Week End: " +
calendar.getTim e().toString() + " = ");

String format = "yyyyMMdd";
return doFormat(format , calendar);
}

private String doFormat(String format, GregorianCalend ar gc){
SimpleDateForma t sdf = new SimpleDateForma t(format);
FieldPosition fpos = new FieldPosition(0 );

StringBuffer b = new StringBuffer();
StringBuffer sb = sdf.format(gc.g etTime(), b, fpos);

return sb.toString();
}

public static void main (String[] args) {

WeekTest wsw = new WeekTest(2002,
GregorianCalend ar.OCTOBER, 6);
System.out.prin tln("Week: " + wsw.getWeek());
System.out.prin tln(wsw.getStar tDate());
System.out.prin tln(wsw.getEndD ate());

WeekTest wsw2 = new WeekTest();
System.out.prin tln("Week: " + wsw2.getWeek()) ;
System.out.prin tln(wsw2.getSta rtDate());
System.out.prin tln(wsw2.getEnd Date());

System.exit(0);
}

}

-end code--------------------------------------

**Tom N** · Jul 17 '05, 10:46 PM

Re: Help with date / calendar calculations.

Date date = ...;

Calendar cal = GregorianCalend ar.getInstance( );
cal.setTime(dat e);
cal.set(cal.HOU R_OF_DAY, 0);
cal.set(cal.MIN UTE, 0);
cal.set(cal.SEC OND, 0);
cal.set(cal.MIL LISECOND, 0);
cal.set(cal.DAY _OF_WEEK, cal.SUNDAY);
Date modifiedDate = cal.getTime();

"cg_news" <cg_news@eart h-N_0_S_P_A_M-link.net> wrote in message
news:vHUYb.9533 $tL3.1889@newsr ead1.news.pas.e arthlink.net...[color=blue]
> cg_news wrote:
>[color=green]
> > In short, what I am trying to do is, based on a date, calculate the week
> > of year (as described in ISO 8601), then calculate the first and last[/color][/color]
date[color=blue][color=green]
> > in this week period and return them in the format CCYYMMDD. Sounds easy
> > enough, right??
> >
> > I am attempting to accomplish this by creating a GregorianCalend er which
> > will get me the week of year. Then by changing the day of week to 1[/color][/color]
(start[color=blue][color=green]
> > of week) i'm trying the get the first day of the week, and day_of_week =[/color][/color]
7[color=blue][color=green]
> > should get me the last. Maybe?
> >
> > I think I may have successfully done this by using an instance of the
> > GregorianCalend ar with the no argument constructor, which appears to
> > default to the current system date/time. However, when I attempt to do[/color][/color]
the[color=blue][color=green]
> > same with the GregorianCalend ar(int year, int month, int date)
> > constructor, it does not work. It seems that my attemps to set the
> > DAY_OF_WEEK value have no effect?
> >
> > Some code samples below,
> > Thanks for any help you can offer...
> > Carl.[/color]
>
> Doh!
> Code:
> -start code--------------------------------------
> import java.text.Field Position;
> import java.text.Simpl eDateFormat;
> import java.util.Grego rianCalendar;
>
>
> public class WeekTest {
>
> private GregorianCalend ar calendar;
>
>
> public WeekTest(Gregor ianCalendar calendar) {
> this.calendar = calendar;
> this.calendar.s etFirstDayOfWee k(GregorianCale ndar.MONDAY);
> this.calendar.s etMinimalDaysIn FirstWeek(4);
> System.out.prin tln("\nStarting as: " +
> calendar.getTim e().toString()) ;
> }
>
> public WeekTest(int year, int month, int date) {
> this(new GregorianCalend ar(year, month, date, 1, 1));
> }
>
>
> public WeekTest() {
> this(new GregorianCalend ar());
> }
>
>
> public String getWeek(){
> String format = "yyyyww";
> return doFormat(format , calendar);
> }
>
>
> public String getStartDate(){
> calendar.set(Gr egorianCalendar .DAY_OF_WEEK,
> GregorianCalend ar.MONDAY);
> calendar.get(Gr egorianCalendar .MILLISECOND);
> System.out.prin t("Week Start: " +
> calendar.getTim e().toString() + " = ");
>
> String format = "yyyyMMdd";
> return doFormat(format , calendar);
> }
>
>
> public String getEndDate(){
> calendar.set(Gr egorianCalendar .DAY_OF_WEEK,
> GregorianCalend ar.SUNDAY);
> System.out.prin t("Week End: " +
> calendar.getTim e().toString() + "[/color]
= ");[color=blue]
>
> String format = "yyyyMMdd";
> return doFormat(format , calendar);
> }
>
>
> private String doFormat(String format, GregorianCalend ar gc){
> SimpleDateForma t sdf = new SimpleDateForma t(format);
> FieldPosition fpos = new FieldPosition(0 );
>
> StringBuffer b = new StringBuffer();
> StringBuffer sb = sdf.format(gc.g etTime(), b, fpos);
>
> return sb.toString();
> }
>
>
> public static void main (String[] args) {
>
> WeekTest wsw = new WeekTest(2002,
> GregorianCalend ar.OCTOBER, 6);
> System.out.prin tln("Week: " + wsw.getWeek());
> System.out.prin tln(wsw.getStar tDate());
> System.out.prin tln(wsw.getEndD ate());
>
>
> WeekTest wsw2 = new WeekTest();
> System.out.prin tln("Week: " + wsw2.getWeek()) ;
> System.out.prin tln(wsw2.getSta rtDate());
> System.out.prin tln(wsw2.getEnd Date());
>
>
> System.exit(0);
> }
>
>
> }
>
> -end code--------------------------------------[/color]

Help with date / calendar calculations.

Help with date / calendar calculations.

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