package java.util; import java.io.Serializable; import ej.annotation.Nullable; /** * TimeZone represents a time zone offset, and also figures out daylight savings. * *

* Typically, you get a TimeZone using getDefault which creates a * TimeZone based on the time zone where the program is running. For example, for a * program running in Japan, getDefault creates a TimeZone object based on * Japanese Standard Time. * *

* You can also get a TimeZone using getTimeZone 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 TimeZone object with:

* * 
 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
 *
* *
You can use the getAvailableIDs method to iterate through all the * supported time zone IDs. You can then choose a supported ID to get a TimeZone. If * the time zone you want is not represented by one of the supported IDs, then a custom time zone ID * can be specified to produce a TimeZone. The syntax of a custom time zone ID is: * *
* * 
 * CustomID:
 *         GMT Sign Hours : Minutes
 *         GMT Sign Hours Minutes
 *         GMT Sign Hours
 * Sign: one of
 *         + -
 * Hours:
 *         Digit
 *         Digit Digit
 * Minutes:
 *         Digit Digit
 * Digit: one of
 *         0 1 2 3 4 5 6 7 8 9
 *
* *
* * Hours must be between 0 to 23 and Minutes must be between 00 to 59. For example, * "GMT+10" and "GMT+0010" mean ten hours and ten minutes ahead of GMT, respectively. *

* The format is locale independent and digits must be taken from the Basic Latin block of the * Unicode standard. No daylight saving time transition schedule can be specified with a custom time * zone ID. If the specified string doesn't match the syntax, "GMT" is used. *

* When creating a TimeZone, the specified custom time zone ID is normalized in the * following syntax:

* * 
 * NormalizedCustomID:
 *         GMT Sign TwoDigitHours : Minutes
 * Sign: one of
 *         + -
 * TwoDigitHours:
 *         Digit Digit
 * Minutes:
 *         Digit Digit
 * Digit: one of
 *         0 1 2 3 4 5 6 7 8 9
 *
* *
For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00". * *

Three-letter time zone IDs

* * @see Calendar */ public abstract class TimeZone implements Cloneable, Serializable { /** * A style specifier for getDisplayName() indicating a long name, such as "Pacific * Standard Time." * * @see #SHORT */ public static final int LONG = 1; /** * A style specifier for getDisplayName() indicating a short name, such as "PST." * * @see #LONG */ public static final int SHORT = 0; /** * Sole constructor. (For invocation by subclass constructors, typically implicit.) */ public TimeZone() { } /** * Gets all the available IDs supported. * * @return an array of IDs. */ public static String[] getAvailableIDs() { throw new RuntimeException(); } /** * Gets the default TimeZone for this host. The source of the default * TimeZone may vary with implementation. * * @return a default TimeZone. */ public static TimeZone getDefault() { throw new RuntimeException(); } /** * Gets the TimeZone for the given ID. * * @param ID * the ID for a TimeZone, either an abbreviation such as "PST", a full name such * as "America/Los_Angeles", or a custom ID such as "GMT-8:00". * * @return the specified TimeZone, or the GMT zone if the given ID cannot be * understood. */ public static TimeZone getTimeZone(String ID) { throw new RuntimeException(); } /** * Creates a copy of this TimeZone. * * @return a clone of this TimeZone */ @Override public Object clone() { throw new RuntimeException(); } /** * Returns the amount of time to be added to local standard time to get local wall clock time. * *

* The default implementation returns 3600000 milliseconds (i.e., one hour) if a call to * {@link #useDaylightTime()} returns {@code true}. Otherwise, 0 (zero) is returned. * *

* If an underlying {@code TimeZone} implementation subclass supports historical and future Daylight * Saving Time schedule changes, this method returns the amount of saving time of the last known * Daylight Saving Time rule that can be a future prediction. * *

* If the amount of saving time at any given time stamp is required, construct a {@link Calendar} * with this {@code TimeZone} and the time stamp, and call {@link Calendar#get(int) * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}. * * @return the amount of saving time in milliseconds * @see #getOffset(long) * @see #getOffset(int,int,int,int,int,int) * @see Calendar#ZONE_OFFSET */ public int getDSTSavings() { throw new RuntimeException(); } /** * Gets the ID of this time zone. * * @return the ID of this time zone. */ public String getID() { throw new RuntimeException(); } /** * 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. *

* This method returns a historically correct offset if an underlying TimeZone * implementation subclass supports historical Daylight Saving Time schedule and GMT offset changes. * * @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 milliseconds in day in standard local time. * * @return the offset in milliseconds to add to GMT to get local time. * * @see Calendar#ZONE_OFFSET * @see Calendar#DST_OFFSET */ public abstract 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. *

* This method returns a historically correct offset value if an underlying TimeZone implementation * subclass supports historical Daylight Saving Time schedule and GMT offset changes. * * @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 */ public int getOffset(long date) { throw new RuntimeException(); } /** * Returns the amount of time in milliseconds to add to UTC to get standard time in this time zone. * Because this value is not affected by daylight saving time, it is called raw offset. *

* If an underlying TimeZone implementation subclass supports historical GMT offset * changes, the method returns the raw offset value of the current date. In Honolulu, for example, * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and this method always returns * -36000000 milliseconds (i.e., -10 hours). * * @return the amount of raw offset time in milliseconds to add to UTC. * @see Calendar#ZONE_OFFSET */ public abstract int getRawOffset(); /** * 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 TimeZone 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 */ public boolean hasSameRules(@Nullable TimeZone other) { throw new RuntimeException(); } /** * Sets the time zone ID. This does not change any other data in the time zone object. * * @param ID * the new time zone ID. */ public void setID(String ID) { throw new RuntimeException(); } /** * Queries if this {@code TimeZone} uses Daylight Saving Time. * *

* If an underlying {@code TimeZone} implementation subclass supports historical and future Daylight * Saving Time schedule changes, this method refers to the last known Daylight Saving Time rule that * can be a future prediction and may not be the same as the current rule. * * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time, {@code false}, * otherwise. * @see Calendar#DST_OFFSET */ public abstract boolean useDaylightTime(); }