com.day.util.TimeZoneUtil Maven / Gradle / Ivy
/*
* $Id: TimeZoneUtil.java 12345 2004-08-22 04:56:09Z fielding $
*
* Copyright 1997-2004 Day Management AG
* Barfuesserplatz 6, 4001 Basel, Switzerland
* All Rights Reserved.
*
* This software is the confidential and proprietary information of
* Day Management AG, ("Confidential Information"). You shall not
* disclose such Confidential Information and shall use it only in
* accordance with the terms of the license agreement you entered into
* with Day.
*/
package com.day.util;
import java.util.*;
import java.text.DecimalFormat;
/**
* The TimeZoneUtil class provides convenience methods for handling
* time zones in Java.
*
* @version $Revision: 1.3 $, $Date: 2004-08-22 06:56:09 +0200 (Sun, 22 Aug 2004) $
* @author mreutegg
* @since echidna
* @audience wad
*/
public class TimeZoneUtil {
private static TimeZone[] zones = null;
private static final DecimalFormat offsetFormatter = new DecimalFormat("00.00");
/**
* Returns an array of TimeZone objects sorted in ascending order
* by their UTC time offset.
*
* @return a sorted array of TimeZone objects.
*/
public synchronized static TimeZone[] getAvailableZones() {
if (zones == null) {
String[] allZones = TimeZone.getAvailableIDs();
// fill a Vector and ignore all three letter id's, but keep UTC
Vector uniqueZones = new Vector();
for (int i=0; i < allZones.length; i++) {
// ignore all three letter id's, but keep UTC
if (allZones[i].length() <= 3 && !allZones[i].equals("UTC")) continue;
TimeZone zone = TimeZone.getTimeZone(allZones[i]);
uniqueZones.add(zone);
}
zones = new TimeZone[0];
zones = (TimeZone[])uniqueZones.toArray(zones);
Arrays.sort(zones, new TimeZoneComparator());
}
// return a copy of the internal array
TimeZone[] retVal = new TimeZone[zones.length];
System.arraycopy(zones, 0, retVal, 0, zones.length);
return retVal;
}
/**
* Returns the TimeZone of the Communiqu? server.
* @return the TimeZone of the Communiqu? server.
*/
public static TimeZone getServerTimeZone() {
return TimeZone.getDefault();
}
/**
* Formats the passed TimeZone object to a String representation:
* [<UTC offset>] <time zone name> (<short name>)
*
Example: [UTC+01.00] Europe/Berlin (CEST)
* @param zone The TimeZone to format
* @return a String representation of the passed TimeZone.
*/
public static String getDisplayName(TimeZone zone) {
StringBuffer buffer = new StringBuffer("[UTC");
if (zone.getRawOffset() >= 0) buffer.append("+");
buffer.append(offsetFormatter.format(((double)zone.getRawOffset())/(1000*60*60)));
buffer.append("] ").append(zone.getID());
buffer.append(" (").append(zone.getDisplayName(true, TimeZone.SHORT));
buffer.append(")");
return buffer.toString();
}
/**
* Inner utility class for comparing two TimeZone objects regarding their UTC
* offset.
*/
static class TimeZoneComparator implements Comparator {
/**
* Compares its two arguments (TimeZone objects) for order.
*
* @param o1 the first object to be compared.
* @param o2 the second object to be compared.
* @return a negative integer, zero, or a positive integer as the
* first argument is less than, equal to, or greater than the
* second.
* @throws ClassCastException if the arguments' types prevent them from
* being compared by this Comparator.
*/
public int compare(Object o1, Object o2) {
int diff = ((TimeZone)o1).getRawOffset() - ((TimeZone)o2).getRawOffset();
return (diff != 0) ? diff : ((TimeZone)o1).getID().compareTo(((TimeZone)o2).getID());
}
}
}