Re: Date calculations

["David Morris" <David.Morris@xxxxxxxxxxxxx>]

Robert,

The Calendar class is contrived and there are better packages
available, but here is something to get you started:

package tests;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.TimeZone;

/**
 * @author dmorris
 *
 * To change this generated comment edit the template variable
"typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public class DateDifference {

    static final int MILLIS_PER_DAY = 24 * 60 * 60 * 1000;

    public static void main(String[] args) {

        // Input date.
        TimeZone mst = TimeZone.getTimeZone("America/Denver");
        GregorianCalendar birthday = new GregorianCalendar(mst);
        birthday.set(2002, Calendar.OCTOBER, 29, 12, 0, 0);

        // now is current time
        GregorianCalendar now = new GregorianCalendar(mst);

        // milliseconds since 1970 Jan 1
        long epochBirthday = birthday.getTime().getTime();
        long epochNow = now.getTime().getTime();
        double hours = (double)(epochBirthday - epochNow) /
MILLIS_PER_DAY;
        System.out.println(hours + " days until my next birthday.");

        GregorianCalendar dayAfter = new GregorianCalendar(mst);
        dayAfter.set(2002, Calendar.OCTOBER, 29, 12, 0, 0);
        dayAfter.add(Calendar.DATE, 1);

        SimpleDateFormat sdf = new SimpleDateFormat("EEEE yyyy/MM/dd
hh:mm:ss aa zz : zzzzzz");
        sdf.setCalendar(dayAfter);
        System.out.println("The day after is: " +
sdf.format(dayAfter.getTime()));
    }
}

You definately want to encapsulate this in something useful.

David Morris

>>> rupshall@psasoft.com 07/18/02 07:27AM >>>
Does java have any date classes that will allow me to do date
calculation
like the date type in RPG?
  ie. newDate = date.addDay(1) ;

Robert



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