Android Open Source - Timetable Date Utils

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.timetable.android.utils;
//from w  ww  . j  a  v a 2s  . c  o m
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class DateUtils {
  
  public static final long DAY_MILLIS = 1000*60*60*24;
  
  public static final long WEEK_MILLIS = 1000*60*60*24*7;
  
  public static final long HOUR_MILLIS = 1000 * 60 * 60;
  
  public static final long MINUTE_MILLIS = 1000 * 60;
  
  public static final int BEFORE = -1;
  
  public static final int EQUALS = 0;
  
  public static final int AFTER = 1;
  
  
  public static long getOffset(long time) {
    return TimeZone.getDefault().getOffset(time);
  }
  
  public static long addOffset(long time) {
    return time + getOffset(time);
  }
  
  public static Date addOffset(Date time) {
    return new Date(addOffset(time.getTime()));
  }
  
  public static long removeOffset(long time) {
    return time - getOffset(time);
  }
  
  public static Date removeOffset(Date time) {
    return new Date(removeOffset(time.getTime()));
  }
  
  /*
   * Try to parse date from string. If string is empty, return null;
   */
  public static Date getDateFromString(SimpleDateFormat format, String dateString) throws ParseException {
    return getDateFromString(format, dateString, true);
  }
  
  /*
   * Try to parse date from string. If string is empty and date can be null, return null.
   */
  public static Date getDateFromString(SimpleDateFormat format, String dateString, boolean canBeNull) throws ParseException {
    if (dateString.isEmpty() && canBeNull) {
      return null;
    }
    return format.parse(dateString);
  }
  
  public static Calendar extractDate(Calendar dateTime) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(extractDate(dateTime.getTime()));
    return cal;
  }
  
  /*
   * Return new date with hours, minutes and second set to zero.
   */
  public static Date extractDate(Date dateTime) {
    /*Calendar cal = Calendar.getInstance();
    cal.setTime(dateTime);
    cal.set(Calendar.HOUR_OF_DAY, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    cal.set(Calendar.MILLISECOND, 0);
    return cal.getTime();
  */
    long localTime = addOffset(dateTime.getTime());
    return removeOffset(new Date(localTime - localTime % DAY_MILLIS));
  }
  
  public static Calendar extractTime(Calendar dateTime) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(extractTime(dateTime.getTime()));
    return cal;
  }
  
  /*
   * Return new date with date set to zero.
   */
  public static Date extractTime(Date dateTime) {
    /*Calendar cal = Calendar.getInstance();
    cal.setTime(dateTime);
    cal.set(Calendar.YEAR, 1970);
    cal.set(Calendar.DAY_OF_YEAR, 1);
    return cal.getTime();
  */
    return new Date(removeOffset(addOffset(dateTime.getTime()) % DAY_MILLIS));
  }
  
  public static Date setTime(Date date, Date time) {
    Calendar ans1 = Calendar.getInstance();
    Calendar ans2 = Calendar.getInstance();
    ans1.setTime(date);
    ans2.setTime(time);
    ans1.set(Calendar.HOUR_OF_DAY, ans2.get(Calendar.HOUR_OF_DAY));
    ans1.set(Calendar.MINUTE, ans2.get(Calendar.MINUTE));
    ans1.set(Calendar.SECOND, ans2.get(Calendar.SECOND));
  
    return ans1.getTime();
  }
  
  public static Date addDay(Date date, int days) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DATE, days);
    return cal.getTime();
  }
  /* 
   * Return true if dates are equal(time does not matter)
   * If one or both dates are null, return false
   */
  public static boolean areSameDates(Date date1, Date date2) {
    if (date1 == null || date2 == null) {
      return false;
    }
    return extractDate(date1).equals(extractDate(date2));
  }
  
  /*
   * Compare first date to second.
   * Time is not considered.
   */
  public static int compareDates(Date first, Date second) {
    int ans = extractDate(first).compareTo(extractDate(second));
    if (ans < 0) return BEFORE;
    else if (ans > 0) return AFTER;
    else return EQUALS;
  }
  
  /* 
   * Compare first time to second.
   * Date is not considered.
   */
  public static int compareTimes(Date first, Date second) {
    int ans = extractTime(first).compareTo(extractTime(second));
    if (ans < 0) return BEFORE;
    else if (ans > 0) return AFTER;
    else return EQUALS;
  }
}

Java Source Code List

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