| /* |
| * @(#)TimeZone.java 1.51 00/01/19 |
| * |
| * Copyright (C) 1996-2005, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| */ |
| |
| package com.ibm.icu.util; |
| |
| import java.io.Serializable; |
| import java.lang.ref.SoftReference; |
| import java.util.Date; |
| import java.util.Hashtable; |
| import java.util.Locale; |
| import com.ibm.icu.impl.JDKTimeZone; |
| import com.ibm.icu.impl.TimeZoneAdapter; |
| import com.ibm.icu.impl.ZoneMeta; |
| import com.ibm.icu.text.SimpleDateFormat; |
| |
| /** |
| * <code>TimeZone</code> represents a time zone offset, and also figures out daylight |
| * savings. |
| * |
| * <p> |
| * Typically, you get a <code>TimeZone</code> using <code>getDefault</code> |
| * which creates a <code>TimeZone</code> based on the time zone where the program |
| * is running. For example, for a program running in Japan, <code>getDefault</code> |
| * creates a <code>TimeZone</code> object based on Japanese Standard Time. |
| * |
| * <p> |
| * You can also get a <code>TimeZone</code> using <code>getTimeZone</code> |
| * along with a time zone ID. For instance, the time zone ID for the |
| * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a |
| * U.S. Pacific Time <code>TimeZone</code> object with: |
| * <blockquote> |
| * <pre> |
| * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles"); |
| * </pre> |
| * </blockquote> |
| * You can use <code>getAvailableIDs</code> method to iterate through |
| * all the supported time zone IDs. You can then choose a |
| * supported ID to get a <code>TimeZone</code>. |
| * If the time zone you want is not represented by one of the |
| * supported IDs, then you can create a custom time zone ID with |
| * the following syntax: |
| * |
| * <blockquote> |
| * <pre> |
| * GMT[+|-]hh[[:]mm] |
| * </pre> |
| * </blockquote> |
| * |
| * For example, you might specify GMT+14:00 as a custom |
| * time zone ID. The <code>TimeZone</code> that is returned |
| * when you specify a custom time zone ID does not include |
| * daylight savings time. |
| * <p> |
| * For compatibility with JDK 1.1.x, some other three-letter time zone IDs |
| * (such as "PST", "CTT", "AST") are also supported. However, <strong>their |
| * use is deprecated</strong> because the same abbreviation is often used |
| * for multiple time zones (for example, "CST" could be U.S. "Central Standard |
| * Time" and "China Standard Time"), and the Java platform can then only |
| * recognize one of them. |
| * |
| * |
| * @see Calendar |
| * @see GregorianCalendar |
| * @see SimpleTimeZone |
| * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu |
| * @stable ICU 2.0 |
| */ |
| abstract public class TimeZone implements Serializable, Cloneable { |
| // using serialver from jdk1.4.2_05 |
| private static final long serialVersionUID = -744942128318337471L; |
| |
| /** |
| * Default constructor. (For invocation by subclass constructors, |
| * typically implicit.) |
| * @stable ICU 2.8 |
| */ |
| public TimeZone() { |
| } |
| |
| /** |
| * A style specifier for <code>getDisplayName()</code> indicating |
| * a short name, such as "PST." |
| * @see #LONG |
| * @stable ICU 2.0 |
| */ |
| public static final int SHORT = 0; |
| |
| /** |
| * A style specifier for <code>getDisplayName()</code> indicating |
| * a long name, such as "Pacific Standard Time." |
| * @see #SHORT |
| * @stable ICU 2.0 |
| */ |
| public static final int LONG = 1; |
| |
| /** |
| * @internal |
| */ |
| private static final int SHORT_GENERIC = 2; |
| |
| /** |
| * @internal |
| */ |
| private static final int LONG_GENERIC = 3; |
| |
| /** |
| * Cache to hold the SimpleDateFormat objects for a Locale. |
| */ |
| private static Hashtable cachedLocaleData = new Hashtable(3); |
| |
| /** |
| * Gets the time zone offset, for current date, modified in case of |
| * daylight savings. This is the offset to add *to* UTC to get local time. |
| * @param era the era of the given date. |
| * @param year the year in the given date. |
| * @param month the month in the given date. |
| * Month is 0-based. e.g., 0 for January. |
| * @param day the day-in-month of the given date. |
| * @param dayOfWeek the day-of-week of the given date. |
| * @param milliseconds the millis in day in <em>standard</em> local time. |
| * @return the offset to add *to* GMT to get local time. |
| * @stable ICU 2.0 |
| */ |
| abstract public int getOffset(int era, int year, int month, int day, |
| int dayOfWeek, int milliseconds); |
| |
| |
| /** |
| * Returns the offset of this time zone from UTC at the specified |
| * date. If Daylight Saving Time is in effect at the specified |
| * date, the offset value is adjusted with the amount of daylight |
| * saving. |
| * |
| * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT |
| * @return the amount of time in milliseconds to add to UTC to get local time. |
| * |
| * @see Calendar#ZONE_OFFSET |
| * @see Calendar#DST_OFFSET |
| * @see #getOffset(long, boolean, int[]) |
| * @stable ICU 2.8 |
| */ |
| public int getOffset(long date) { |
| int[] result = new int[2]; |
| getOffset(date, false, result); |
| return result[0]+result[1]; |
| } |
| |
| /** |
| * Returns the time zone raw and GMT offset for the given moment |
| * in time. Upon return, local-millis = GMT-millis + rawOffset + |
| * dstOffset. All computations are performed in the proleptic |
| * Gregorian calendar. The default implementation in the TimeZone |
| * class delegates to the 8-argument getOffset(). |
| * |
| * @param date moment in time for which to return offsets, in |
| * units of milliseconds from January 1, 1970 0:00 GMT, either GMT |
| * time or local wall time, depending on `local'. |
| * @param local if true, `date' is local wall time; otherwise it |
| * is in GMT time. |
| * @param offsets output parameter to receive the raw offset, that |
| * is, the offset not including DST adjustments, in offsets[0], |
| * and the DST offset, that is, the offset to be added to |
| * `rawOffset' to obtain the total offset between local and GMT |
| * time, in offsets[1]. If DST is not in effect, the DST offset is |
| * zero; otherwise it is a positive value, typically one hour. |
| * |
| * @stable ICU 2.8 |
| */ |
| public void getOffset(long date, boolean local, int[] offsets) { |
| offsets[0] = getRawOffset(); |
| |
| // Convert to local wall millis if necessary |
| if (!local) { |
| date += offsets[0]; // now in local standard millis |
| } |
| |
| // When local==FALSE, we might have to recompute. This loop is |
| // executed once, unless a recomputation is required; then it is |
| // executed twice. |
| for (int pass=0; ; ++pass) { |
| int fields[] = new int[4]; |
| long day = floorDivide(date, MILLIS_PER_DAY, fields); |
| int millis = fields[0]; |
| |
| computeGregorianFields(day, fields); |
| |
| offsets[1] = getOffset(GregorianCalendar.AD, |
| fields[0], fields[1], fields[2], |
| fields[3], millis) - offsets[0]; |
| |
| // Recompute if local==FALSE, dstOffset!=0, and addition of |
| // the dstOffset puts us in a different day. |
| if (pass!=0 || local || offsets[1]==0) { |
| break; |
| } |
| date += offsets[1]; |
| if (floorDivide(date, MILLIS_PER_DAY) == day) { |
| break; |
| } |
| } |
| } |
| |
| /** |
| * Divide two long integers, returning the floor of the quotient. |
| * <p> |
| * Unlike the built-in division, this is mathematically well-behaved. |
| * E.g., <code>-1/4</code> => 0 |
| * but <code>floorDivide(-1,4)</code> => -1. |
| * TODO: This duplicates a method in Calendar; clean up and |
| * consolidate in ICU 3.0. |
| * @param numerator the numerator |
| * @param denominator a divisor which must be > 0 |
| * @return the floor of the quotient. |
| */ |
| static long floorDivide(long numerator, long denominator) { |
| // We do this computation in order to handle |
| // a numerator of Long.MIN_VALUE correctly |
| return (numerator >= 0) ? |
| numerator / denominator : |
| ((numerator + 1) / denominator) - 1; |
| } |
| |
| /** |
| * Divide two integers, returning the floor of the quotient, and |
| * the modulus remainder. |
| * <p> |
| * Unlike the built-in division, this is mathematically well-behaved. |
| * E.g., <code>-1/4</code> => 0 and <code>-1%4</code> => -1, |
| * but <code>floorDivide(-1,4)</code> => -1 with <code>remainder[0]</code> => 3. |
| * TODO: This duplicates a method in Calendar; clean up and |
| * consolidate in ICU 3.0. |
| * @param numerator the numerator |
| * @param denominator a divisor which must be > 0 |
| * @param remainder an array of at least one element in which the value |
| * <code>numerator mod denominator</code> is returned. Unlike <code>numerator |
| * % denominator</code>, this will always be non-negative. |
| * @return the floor of the quotient. |
| */ |
| static int floorDivide(long numerator, int denominator, int[] remainder) { |
| if (numerator >= 0) { |
| remainder[0] = (int)(numerator % denominator); |
| return (int)(numerator / denominator); |
| } |
| int quotient = (int)(((numerator + 1) / denominator) - 1); |
| remainder[0] = (int)(numerator - (quotient * denominator)); |
| return quotient; |
| } |
| |
| /** |
| * Compute the Gregorian calendar year, month, and day of month |
| * from the epoch day, and return them in the given array. |
| * TODO: This duplicates a method in Calendar; clean up and |
| * consolidate in ICU 3.0. |
| */ |
| static void computeGregorianFields(long day, int fields[]) { |
| int year, month, dayOfMonth, dayOfYear; |
| |
| // Convert from 1970 CE epoch to 1 CE epoch (Gregorian calendar) |
| // JULIAN_1_CE = 1721426; // January 1, 1 CE Gregorian |
| // JULIAN_1970_CE = 2440588; // January 1, 1970 CE Gregorian |
| day += (2440588 - 1721426); |
| |
| // Here we convert from the day number to the multiple radix |
| // representation. We use 400-year, 100-year, and 4-year cycles. |
| // For example, the 4-year cycle has 4 years + 1 leap day; giving |
| // 1461 == 365*4 + 1 days. |
| int[] rem = new int[1]; |
| int n400 = floorDivide(day, 146097, rem); // 400-year cycle length |
| int n100 = floorDivide(rem[0], 36524, rem); // 100-year cycle length |
| int n4 = floorDivide(rem[0], 1461, rem); // 4-year cycle length |
| int n1 = floorDivide(rem[0], 365, rem); |
| year = 400*n400 + 100*n100 + 4*n4 + n1; |
| dayOfYear = rem[0]; // zero-based day of year |
| if (n100 == 4 || n1 == 4) { |
| dayOfYear = 365; // Dec 31 at end of 4- or 400-yr cycle |
| } else { |
| ++year; |
| } |
| |
| boolean isLeap = ((year&0x3) == 0) && // equiv. to (year%4 == 0) |
| (year%100 != 0 || year%400 == 0); |
| |
| int correction = 0; |
| int march1 = isLeap ? 60 : 59; // zero-based DOY for March 1 |
| if (dayOfYear >= march1) correction = isLeap ? 1 : 2; |
| month = (12 * (dayOfYear + correction) + 6) / 367; // zero-based month |
| dayOfMonth = dayOfYear - |
| GREGORIAN_MONTH_COUNT[month][isLeap?1:0] + 1; // one-based DOM |
| |
| // Jan 1 1 CE is Monday |
| int dayOfWeek = (int) ((day + Calendar.MONDAY) % 7); |
| if (dayOfWeek < Calendar.SUNDAY) { |
| dayOfWeek += 7; |
| } |
| |
| fields[0] = year; |
| fields[1] = month; // 0-based already |
| fields[2] = dayOfMonth; // 1-based already |
| fields[3] = dayOfWeek; // 1-based already |
| //fields[4] = dayOfYear + 1; // Convert from 0-based to 1-based |
| } |
| |
| /** |
| * The number of milliseconds in one day. |
| */ |
| static final int MILLIS_PER_DAY = 24*60*60*1000; |
| |
| /** |
| * For each month, the days in a non-leap year before the start |
| * the of month, and the days in a leap year before the start of |
| * the month. |
| * TODO: This duplicates data in Calendar.java; clean up and |
| * consolidate in ICU 3.0. |
| */ |
| static final int[][] GREGORIAN_MONTH_COUNT = { |
| { 0, 0 }, // Jan |
| { 31, 31 }, // Feb |
| { 59, 60 }, // Mar |
| { 90, 91 }, // Apr |
| { 120, 121 }, // May |
| { 151, 152 }, // Jun |
| { 181, 182 }, // Jul |
| { 212, 213 }, // Aug |
| { 243, 244 }, // Sep |
| { 273, 274 }, // Oct |
| { 304, 305 }, // Nov |
| { 334, 335 } // Dec |
| }; |
| |
| /** |
| * Sets the base time zone offset to GMT. |
| * This is the offset to add *to* UTC to get local time. |
| * @param offsetMillis the given base time zone offset to GMT. |
| * @stable ICU 2.0 |
| */ |
| abstract public void setRawOffset(int offsetMillis); |
| |
| /** |
| * Gets unmodified offset, NOT modified in case of daylight savings. |
| * This is the offset to add *to* UTC to get local time. |
| * @return the unmodified offset to add *to* UTC to get local time. |
| * @stable ICU 2.0 |
| */ |
| abstract public int getRawOffset(); |
| |
| /** |
| * Gets the ID of this time zone. |
| * @return the ID of this time zone. |
| * @stable ICU 2.0 |
| */ |
| public String getID() { |
| return ID; |
| } |
| |
| /** |
| * Sets the time zone ID. This does not change any other data in |
| * the time zone object. |
| * @param ID the new time zone ID. |
| * @stable ICU 2.0 |
| */ |
| public void setID(String ID) { |
| if (ID == null) { |
| throw new NullPointerException(); |
| } |
| this.ID = ID; |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the default locale. |
| * This method returns the long generic name. |
| * If the display name is not available for the locale, |
| * a fallback based on the country, city, or time zone id will be used. |
| * @return the human-readable name of this time zone in the default locale. |
| * @stable ICU 2.0 |
| */ |
| public final String getDisplayName() { |
| return _getDisplayName(false, LONG_GENERIC, ULocale.getDefault()); |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the specified locale. |
| * This method returns the long generic name. |
| * If the display name is not available for the locale, |
| * a fallback based on the country, city, or time zone id will be used. |
| * @param locale the locale in which to supply the display name. |
| * @return the human-readable name of this time zone in the given locale |
| * or in the default locale if the given locale is not recognized. |
| * @stable ICU 2.0 |
| */ |
| public final String getDisplayName(Locale locale) { |
| return _getDisplayName(false, LONG_GENERIC, ULocale.forLocale(locale)); |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the specified locale. |
| * This method returns the long name, not including daylight savings. |
| * If the display name is not available for the locale, |
| * a fallback based on the country, city, or time zone id will be used. |
| * @param locale the ulocale in which to supply the display name. |
| * @return the human-readable name of this time zone in the given locale |
| * or in the default ulocale if the given ulocale is not recognized. |
| * @draft ICU 3.2 |
| * @deprecated This is a draft API and might change in a future release of ICU. |
| */ |
| public final String getDisplayName(ULocale locale) { |
| return _getDisplayName(false, LONG_GENERIC, locale); |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the default locale. |
| * If the display name is not available for the locale, |
| * then this method returns a string in the format |
| * <code>GMT[+-]hh:mm</code>. |
| * @param daylight if true, return the daylight savings name. |
| * @param style either <code>LONG</code> or <code>SHORT</code> |
| * @return the human-readable name of this time zone in the default locale. |
| * @stable ICU 2.0 |
| */ |
| public final String getDisplayName(boolean daylight, int style) { |
| return getDisplayName(daylight, style, ULocale.getDefault()); |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the specified locale. |
| * If the display name is not available for the locale, |
| * then this method returns a string in the format |
| * <code>GMT[+-]hh:mm</code>. |
| * @param daylight if true, return the daylight savings name. |
| * @param style either <code>LONG</code> or <code>SHORT</code> |
| * @param locale the locale in which to supply the display name. |
| * @return the human-readable name of this time zone in the given locale |
| * or in the default locale if the given locale is not recognized. |
| * @exception IllegalArgumentException style is invalid. |
| * @stable ICU 2.0 |
| */ |
| public String getDisplayName(boolean daylight, int style, Locale locale) { |
| return getDisplayName(daylight, style, ULocale.forLocale(locale)); |
| } |
| |
| /** |
| * Returns a name of this time zone suitable for presentation to the user |
| * in the specified locale. |
| * If the display name is not available for the locale, |
| * then this method returns a string in the format |
| * <code>GMT[+-]hh:mm</code>. |
| * @param daylight if true, return the daylight savings name. |
| * @param style either <code>LONG</code> or <code>SHORT</code> |
| * @param locale the locale in which to supply the display name. |
| * @return the human-readable name of this time zone in the given locale |
| * or in the default locale if the given locale is not recognized. |
| * @exception IllegalArgumentException style is invalid. |
| * @draft ICU 3.2 |
| * @deprecated This is a draft API and might change in a future release of ICU. |
| */ |
| public String getDisplayName(boolean daylight, int style, ULocale locale) { |
| if (style != SHORT && style != LONG) { |
| throw new IllegalArgumentException("Illegal style: " + style); |
| } |
| return _getDisplayName(daylight, style, locale); |
| } |
| |
| /** |
| * The public version of this API only accepts LONG/SHORT, the |
| * internal version (which this calls) also accepts LONG_GENERIC/SHORT_GENERIC. |
| * @internal |
| */ |
| private String _getDisplayName(boolean daylight, int style, ULocale locale) { |
| /* NOTES: |
| * (1) We use SimpleDateFormat for simplicity; we could do this |
| * more efficiently but it would duplicate the SimpleDateFormat code |
| * here, which is undesirable. |
| * (2) Attempts to move the code from SimpleDateFormat to here also run |
| * aground because this requires SimpleDateFormat to keep a Locale |
| * object around, which it currently doesn't; to synthesize such a |
| * locale upon resurrection; and to somehow handle the special case of |
| * construction from a DateFormatSymbols object. |
| */ |
| |
| // We keep a cache, indexed by locale. The cache contains a |
| // SimpleDateFormat object, which we create on demand. |
| SoftReference data = (SoftReference)cachedLocaleData.get(locale); |
| SimpleDateFormat format; |
| if (data == null || |
| (format = (SimpleDateFormat)data.get()) == null) { |
| format = new SimpleDateFormat(null, locale); |
| cachedLocaleData.put(locale, new SoftReference(format)); |
| } |
| // Create a new SimpleTimeZone as a stand-in for this zone; the stand-in |
| // will have no DST, or DST during January, but the same ID and offset, |
| // and hence the same display name. We don't cache these because |
| // they're small and cheap to create. |
| SimpleTimeZone tz; |
| if (daylight && useDaylightTime()) { |
| int savings = getDSTSavings(); |
| tz = new SimpleTimeZone(getRawOffset(), getID(), |
| Calendar.JANUARY, 1, 0, 0, |
| Calendar.FEBRUARY, 1, 0, 0, |
| savings); |
| } else { |
| tz = new SimpleTimeZone(getRawOffset(), getID()); |
| } |
| String[] patterns = { "z", "zzzz", "v", "vvvv" }; |
| format.applyPattern(patterns[style]); |
| format.setTimeZone(tz); |
| // Format a date in January. We use the value 10*ONE_DAY == Jan 11 1970 |
| // 0:00 GMT. |
| return format.format(new Date(864000000L)); |
| } |
| |
| /** |
| * Returns the amount of time to be added to local standard time |
| * to get local wall clock time. |
| * <p> |
| * The default implementation always returns 3600000 milliseconds |
| * (i.e., one hour) if this time zone observes Daylight Saving |
| * Time. Otherwise, 0 (zero) is returned. |
| * <p> |
| * If an underlying TimeZone implementation subclass supports |
| * historical Daylight Saving Time changes, this method returns |
| * the known latest daylight saving value. |
| * |
| * @return the amount of saving time in milliseconds |
| * @stable ICU 2.8 |
| */ |
| public int getDSTSavings() { |
| if (useDaylightTime()) { |
| return 3600000; |
| } |
| return 0; |
| } |
| |
| /** |
| * Queries if this time zone uses daylight savings time. |
| * @return true if this time zone uses daylight savings time, |
| * false, otherwise. |
| * @stable ICU 2.0 |
| */ |
| abstract public boolean useDaylightTime(); |
| |
| /** |
| * Queries if the given date is in daylight savings time in |
| * this time zone. |
| * @param date the given Date. |
| * @return true if the given date is in daylight savings time, |
| * false, otherwise. |
| * @stable ICU 2.0 |
| */ |
| abstract public boolean inDaylightTime(Date date); |
| |
| /** |
| * Gets the <code>TimeZone</code> for the given ID. |
| * |
| * @param ID the ID for a <code>TimeZone</code>, either an abbreviation |
| * such as "PST", a full name such as "America/Los_Angeles", or a custom |
| * ID such as "GMT-8:00". Note that the support of abbreviations is |
| * for JDK 1.1.x compatibility only and full names should be used. |
| * |
| * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID |
| * cannot be understood. |
| * @stable ICU 2.0 |
| */ |
| public static synchronized TimeZone getTimeZone(String ID) { |
| // (not for 3.4) ID = ZoneMeta.getCanonicalID(ID); |
| return JDKTimeZone.wrap(java.util.TimeZone.getTimeZone(ID)); |
| } |
| |
| /** |
| * Return a new String array containing all system TimeZone IDs |
| * with the given raw offset from GMT. These IDs may be passed to |
| * <code>get()</code> to construct the corresponding TimeZone |
| * object. |
| * @param rawOffset the offset in milliseconds from GMT |
| * @return an array of IDs for system TimeZones with the given |
| * raw offset. If there are none, return a zero-length array. |
| * @stable ICU 2.0 |
| */ |
| public static String[] getAvailableIDs(int rawOffset) { |
| return java.util.TimeZone.getAvailableIDs(rawOffset); |
| } |
| |
| /** |
| * Return a new String array containing all system TimeZone IDs |
| * associated with the given country. These IDs may be passed to |
| * <code>get()</code> to construct the corresponding TimeZone |
| * object. |
| * @param country a two-letter ISO 3166 country code, or <code>null</code> |
| * to return zones not associated with any country |
| * @return an array of IDs for system TimeZones in the given |
| * country. If there are none, return a zero-length array. |
| * @stable ICU 2.0 |
| */ |
| public static String[] getAvailableIDs(String country) { |
| return ZoneMeta.getAvailableIDs(country); |
| } |
| |
| /** |
| * Return a new String array containing all system TimeZone IDs. |
| * These IDs (and only these IDs) may be passed to |
| * <code>get()</code> to construct the corresponding TimeZone |
| * object. |
| * @return an array of all system TimeZone IDs |
| * @stable ICU 2.0 |
| */ |
| public static String[] getAvailableIDs() { |
| return java.util.TimeZone.getAvailableIDs(); |
| } |
| |
| /** |
| * Returns the number of IDs in the equivalency group that |
| * includes the given ID. An equivalency group contains zones |
| * that have the same GMT offset and rules. |
| * |
| * <p>The returned count includes the given ID; it is always >= 1 |
| * for valid IDs. The given ID must be a system time zone. If it |
| * is not, returns zero. |
| * @param id a system time zone ID |
| * @return the number of zones in the equivalency group containing |
| * 'id', or zero if 'id' is not a valid system ID |
| * @see #getEquivalentID |
| * @stable ICU 2.0 |
| */ |
| public static int countEquivalentIDs(String id) { |
| return ZoneMeta.countEquivalentIDs(id); |
| } |
| |
| /** |
| * Returns an ID in the equivalency group that |
| * includes the given ID. An equivalency group contains zones |
| * that have the same GMT offset and rules. |
| * |
| * <p>The given index must be in the range 0..n-1, where n is the |
| * value returned by <code>countEquivalentIDs(id)</code>. For |
| * some value of 'index', the returned value will be equal to the |
| * given id. If the given id is not a valid system time zone, or |
| * if 'index' is out of range, then returns an empty string. |
| * @param id a system time zone ID |
| * @param index a value from 0 to n-1, where n is the value |
| * returned by <code>countEquivalentIDs(id)</code> |
| * @return the ID of the index-th zone in the equivalency group |
| * containing 'id', or an empty string if 'id' is not a valid |
| * system ID or 'index' is out of range |
| * @see #countEquivalentIDs |
| * @stable ICU 2.0 |
| */ |
| public static String getEquivalentID(String id, int index) { |
| return ZoneMeta.getEquivalentID(id, index); |
| } |
| |
| /** |
| * Gets the default <code>TimeZone</code> for this host. |
| * The source of the default <code>TimeZone</code> |
| * may vary with implementation. |
| * @return a default <code>TimeZone</code>. |
| * @stable ICU 2.0 |
| */ |
| public static synchronized TimeZone getDefault() { |
| if (defaultZone == null) { |
| defaultZone = JDKTimeZone.wrap(java.util.TimeZone.getDefault()); |
| } |
| return (TimeZone) defaultZone.clone(); |
| } |
| |
| /** |
| * Sets the <code>TimeZone</code> that is |
| * returned by the <code>getDefault</code> method. If <code>zone</code> |
| * is null, reset the default to the value it had originally when the |
| * VM first started. |
| * @param tz the new default time zone |
| * @stable ICU 2.0 |
| */ |
| public static synchronized void setDefault(TimeZone tz) { |
| defaultZone = tz; |
| // Keep java.util.TimeZone default in sync so java.util.Date |
| // can interoperate with com.ibm.icu.util classes. |
| java.util.TimeZone jdkZone = null; |
| if (tz != null) { |
| jdkZone = TimeZoneAdapter.wrap(tz); |
| } |
| java.util.TimeZone.setDefault(jdkZone); |
| } |
| |
| /** |
| * Returns true if this zone has the same rule and offset as another zone. |
| * That is, if this zone differs only in ID, if at all. Returns false |
| * if the other zone is null. |
| * @param other the <code>TimeZone</code> object to be compared with |
| * @return true if the other zone is not null and is the same as this one, |
| * with the possible exception of the ID |
| * @stable ICU 2.0 |
| */ |
| public boolean hasSameRules(TimeZone other) { |
| return other != null && |
| getRawOffset() == other.getRawOffset() && |
| useDaylightTime() == other.useDaylightTime(); |
| } |
| |
| /** |
| * Overrides Cloneable |
| * @stable ICU 2.0 |
| */ |
| public Object clone() { |
| try { |
| TimeZone other = (TimeZone) super.clone(); |
| other.ID = ID; |
| return other; |
| } catch (CloneNotSupportedException e) { |
| throw new InternalError(); |
| } |
| } |
| |
| // =======================privates=============================== |
| |
| /** |
| * The string identifier of this <code>TimeZone</code>. This is a |
| * programmatic identifier used internally to look up <code>TimeZone</code> |
| * objects from the system table and also to map them to their localized |
| * display names. <code>ID</code> values are unique in the system |
| * table but may not be for dynamically created zones. |
| * @serial |
| */ |
| private String ID; |
| |
| /** |
| * The default time zone, or null if not set. |
| */ |
| private static TimeZone defaultZone = null; |
| } |
| |
| //eof |
