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package sun.util.calendar;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
* <code>CalendarSystem</code> is an abstract class that defines the
* programming interface to deal with calendar date and time.
*
* <p><code>CalendarSystem</code> instances are singletons. For
* example, there exists only one Gregorian calendar instance in the
* Java runtime environment. A singleton instance can be obtained
* calling one of the static factory methods.
*
* <h4>CalendarDate</h4>
*
* <p>For the methods in a <code>CalendarSystem</code> that manipulate
* a <code>CalendarDate</code>, <code>CalendarDate</code>s that have
* been created by the <code>CalendarSystem</code> must be
* specified. Otherwise, the methods throw an exception. This is
* because, for example, a Chinese calendar date can't be understood
* by the Hebrew calendar system.
*
* <h4>Calendar names</h4>
*
* Each calendar system has a unique name to be identified. The Java
* runtime in this release supports the following calendar systems.
*
* <pre>
* Name Calendar System
* ---------------------------------------
* gregorian Gregorian Calendar
* julian Julian Calendar
* japanese Japanese Imperial Calendar
* </pre>
*
* @see CalendarDate
* @author Masayoshi Okutsu
* @since 1.5
*/
public abstract class CalendarSystem {
/////////////////////// Calendar Factory Methods /////////////////////////
private static volatile boolean initialized;
// Map of calendar names and calendar class names
private static ConcurrentMap<String, String> names;
// Map of calendar names and CalendarSystem instances
private static ConcurrentMap<String,CalendarSystem> calendars;
private static final String PACKAGE_NAME = "sun.util.calendar.";
private static final String[] namePairs = {
"gregorian", "Gregorian",
"japanese", "LocalGregorianCalendar",
"julian", "JulianCalendar",
/*
"hebrew", "HebrewCalendar",
"iso8601", "ISOCalendar",
"taiwanese", "LocalGregorianCalendar",
"thaibuddhist", "LocalGregorianCalendar",
*/
};
private static void initNames() {
ConcurrentMap<String,String> nameMap = new ConcurrentHashMap<>();
// Associate a calendar name with its class name and the
// calendar class name with its date class name.
StringBuilder clName = new StringBuilder();
for (int i = 0; i < namePairs.length; i += 2) {
clName.setLength(0);
String cl = clName.append(PACKAGE_NAME).append(namePairs[i+1]).toString();
nameMap.put(namePairs[i], cl);
}
synchronized (CalendarSystem.class) {
if (!initialized) {
names = nameMap;
calendars = new ConcurrentHashMap<>();
initialized = true;
}
}
}
private static final Gregorian GREGORIAN_INSTANCE = new Gregorian();
/**
* Returns the singleton instance of the <code>Gregorian</code>
* calendar system.
*
* @return the <code>Gregorian</code> instance
*/
public static Gregorian getGregorianCalendar() {
return GREGORIAN_INSTANCE;
}
/**
* Returns a <code>CalendarSystem</code> specified by the calendar
* name. The calendar name has to be one of the supported calendar
* names.
*
* @param calendarName the calendar name
* @return the <code>CalendarSystem</code> specified by
* <code>calendarName</code>, or null if there is no
* <code>CalendarSystem</code> associated with the given calendar name.
*/
public static CalendarSystem forName(String calendarName) {
if ("gregorian".equals(calendarName)) {
return GREGORIAN_INSTANCE;
}
if (!initialized) {
initNames();
}
CalendarSystem cal = calendars.get(calendarName);
if (cal != null) {
return cal;
}
String className = names.get(calendarName);
if (className == null) {
return null; // Unknown calendar name
}
if (className.endsWith("LocalGregorianCalendar")) {
// Create the specific kind of local Gregorian calendar system
cal = LocalGregorianCalendar.getLocalGregorianCalendar(calendarName);
} else {
try {
@SuppressWarnings("deprecation")
Object tmp = Class.forName(className).newInstance();
cal = (CalendarSystem) tmp;
} catch (Exception e) {
throw new InternalError(e);
}
}
if (cal == null) {
return null;
}
CalendarSystem cs = calendars.putIfAbsent(calendarName, cal);
return (cs == null) ? cal : cs;
}
//////////////////////////////// Calendar API //////////////////////////////////
/**
* Returns the name of this calendar system.
*/
public abstract String getName();
public abstract CalendarDate getCalendarDate();
/**
* Calculates calendar fields from the specified number of
* milliseconds since the Epoch, January 1, 1970 00:00:00 UTC
* (Gregorian). This method doesn't check overflow or underflow
* when adjusting the millisecond value (representing UTC) with
* the time zone offsets (i.e., the GMT offset and amount of
* daylight saving).
*
* @param millis the offset value in milliseconds from January 1,
* 1970 00:00:00 UTC (Gregorian).
* @return a <code>CalendarDate</code> instance that contains the
* calculated calendar field values.
*/
public abstract CalendarDate getCalendarDate(long millis);
public abstract CalendarDate getCalendarDate(long millis, CalendarDate date);
public abstract CalendarDate getCalendarDate(long millis, TimeZone zone);
/**
* Constructs a <code>CalendarDate</code> that is specific to this
* calendar system. All calendar fields have their initial
* values. The {@link TimeZone#getDefault() default time zone} is
* set to the instance.
*
* @return a <code>CalendarDate</code> instance that contains the initial
* calendar field values.
*/
public abstract CalendarDate newCalendarDate();
public abstract CalendarDate newCalendarDate(TimeZone zone);
/**
* Returns the number of milliseconds since the Epoch, January 1,
* 1970 00:00:00 UTC (Gregorian), represented by the specified
* <code>CalendarDate</code>.
*
* @param date the <code>CalendarDate</code> from which the time
* value is calculated
* @return the number of milliseconds since the Epoch.
*/
public abstract long getTime(CalendarDate date);
/**
* Returns the length in days of the specified year by
* <code>date</code>. This method does not perform the
* normalization with the specified <code>CalendarDate</code>. The
* <code>CalendarDate</code> must be normalized to get a correct
* value.
*/
public abstract int getYearLength(CalendarDate date);
/**
* Returns the number of months of the specified year. This method
* does not perform the normalization with the specified
* <code>CalendarDate</code>. The <code>CalendarDate</code> must
* be normalized to get a correct value.
*/
public abstract int getYearLengthInMonths(CalendarDate date);
/**
* Returns the length in days of the month specified by the calendar
* date. This method does not perform the normalization with the
* specified calendar date. The <code>CalendarDate</code> must
* be normalized to get a correct value.
*
* @param date the date from which the month value is obtained
* @return the number of days in the month
* @exception IllegalArgumentException if the specified calendar date
* doesn't have a valid month value in this calendar system.
*/
public abstract int getMonthLength(CalendarDate date); // no setter
/**
* Returns the length in days of a week in this calendar
* system. If this calendar system has multiple radix weeks, this
* method returns only one of them.
*/
public abstract int getWeekLength();
/**
* Returns the <code>Era</code> designated by the era name that
* has to be known to this calendar system. If no Era is
* applicable to this calendar system, null is returned.
*
* @param eraName the name of the era
* @return the <code>Era</code> designated by
* <code>eraName</code>, or <code>null</code> if no Era is
* applicable to this calendar system or the specified era name is
* not known to this calendar system.
*/
public abstract Era getEra(String eraName);
/**
* Returns valid <code>Era</code>s of this calendar system. The
* return value is sorted in the descendant order. (i.e., the first
* element of the returned array is the oldest era.) If no era is
* applicable to this calendar system, <code>null</code> is returned.
*
* @return an array of valid <code>Era</code>s, or
* <code>null</code> if no era is applicable to this calendar
* system.
*/
public abstract Era[] getEras();
/**
* @throws IllegalArgumentException if the specified era name is
* unknown to this calendar system.
* @see Era
*/
public abstract void setEra(CalendarDate date, String eraName);
/**
* Returns a <code>CalendarDate</code> of the n-th day of week
* which is on, after or before the specified date. For example, the
* first Sunday in April 2002 (Gregorian) can be obtained as
* below:
*
* <pre><code>
* Gregorian cal = CalendarSystem.getGregorianCalendar();
* CalendarDate date = cal.newCalendarDate();
* date.setDate(2004, cal.APRIL, 1);
* CalendarDate firstSun = cal.getNthDayOfWeek(1, cal.SUNDAY, date);
* // firstSun represents April 4, 2004.
* </code></pre>
*
* This method returns a new <code>CalendarDate</code> instance
* and doesn't modify the original date.
*
* @param nth specifies the n-th one. A positive number specifies
* <em>on or after</em> the <code>date</code>. A non-positive number
* specifies <em>on or before</em> the <code>date</code>.
* @param dayOfWeek the day of week
* @param date the date
* @return the date of the nth <code>dayOfWeek</code> after
* or before the specified <code>CalendarDate</code>
*/
public abstract CalendarDate getNthDayOfWeek(int nth, int dayOfWeek,
CalendarDate date);
public abstract CalendarDate setTimeOfDay(CalendarDate date, int timeOfDay);
/**
* Checks whether the calendar fields specified by <code>date</code>
* represents a valid date and time in this calendar system. If the
* given date is valid, <code>date</code> is marked as <em>normalized</em>.
*
* @param date the <code>CalendarDate</code> to be validated
* @return <code>true</code> if all the calendar fields are consistent,
* otherwise, <code>false</code> is returned.
* @exception NullPointerException if the specified
* <code>date</code> is <code>null</code>
*/
public abstract boolean validate(CalendarDate date);
/**
* Normalizes calendar fields in the specified
* <code>date</code>. Also all {@link CalendarDate#FIELD_UNDEFINED
* undefined} fields are set to correct values. The actual
* normalization process is calendar system dependent.
*
* @param date the calendar date to be validated
* @return <code>true</code> if all fields have been normalized;
* <code>false</code> otherwise.
* @exception NullPointerException if the specified
* <code>date</code> is <code>null</code>
*/
public abstract boolean normalize(CalendarDate date);
}