* Subclasses of {@code Calendar} interpret a {@code Date} * according to the rules of a specific calendar system. * *
* Like other locale-sensitive classes, {@code Calendar} provides a class * method, {@code getInstance}, for getting a default instance of * this class for general use. {@code Calendar}'s {@code getInstance} method * returns a calendar whose locale is based on system settings and whose time fields * have been initialized with the current date and time:
* ** *Calendar rightNow = Calendar.getInstance()* *
* A {@code Calendar} object can produce all the time field values needed * to implement the date-time formatting for a particular language and calendar * style (for example, Japanese-Gregorian, Japanese-Traditional). * {@code Calendar} defines the range of values returned by certain * fields, as well as their meaning. For example, the first month of the year * has value {@code MONTH} == {@code JANUARY} for all calendars. * Other values are defined by the concrete subclass, such as {@code ERA} * and {@code YEAR}. See individual field documentation and subclass * documentation for details. * *
* When a {@code Calendar} is lenient, it accepts a wider * range of field values than it produces. For example, a lenient * {@code GregorianCalendar} interprets {@code MONTH} == * {@code JANUARY}, {@code DAY_OF_MONTH} == 32 as February 1. A * non-lenient {@code GregorianCalendar} throws an exception when given * out-of-range field settings. When calendars recompute field values for return * by {@code get()}, they normalize them. For example, a * {@code GregorianCalendar} always produces {@code DAY_OF_MONTH} * values between 1 and the length of the month. * *
* {@code Calendar} defines a locale-specific seven day week using two * parameters: the first day of the week and the minimal days in first week * (from 1 to 7). These numbers are taken from the locale resource data when a * {@code Calendar} is constructed. They may also be specified explicitly * through the API. * *
* When setting or getting the {@code WEEK_OF_MONTH} or * {@code WEEK_OF_YEAR} fields, {@code Calendar} must determine * the first week of the month or year as a reference point. The first week of a * month or year is defined as the earliest seven day period beginning on * {@code getFirstDayOfWeek()} and containing at least * {@code getMinimalDaysInFirstWeek()} days of that month or year. Weeks * numbered ..., -1, 0 precede the first week; weeks numbered 2, 3,... follow * it. Note that the normalized numbering returned by {@code get()} may * be different. For example, a specific {@code Calendar} subclass may * designate the week before week 1 of a year as week n of the * previous year. * *
* When computing a {@code Date} from time fields, two special * circumstances may arise: there may be insufficient information to compute the * {@code Date} (such as only year and month but no day in the month), or * there may be inconsistent information (such as "Tuesday, July 15, 1996" -- * July 15, 1996 is actually a Monday). * *
* Insufficient information. The calendar will use default * information to specify the missing fields. This may vary by calendar; for the * Gregorian calendar, the default for a field is the same as that of the start * of the epoch: i.e., YEAR = 1970, MONTH = JANUARY, DATE = 1, etc. * *
* Inconsistent information. If fields conflict, the calendar * will give preference to fields set more recently. For example, when * determining the day, the calendar will look for one of the following * combinations of fields. The most recent combination, as determined by the * most recently set single field, will be used. * *
* ** * For the time of day: * ** MONTH + DAY_OF_MONTH * MONTH + WEEK_OF_MONTH + DAY_OF_WEEK * MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK * DAY_OF_YEAR * DAY_OF_WEEK + WEEK_OF_YEAR* *
* ** ** HOUR_OF_DAY * AM_PM + HOUR* *
* Note: There are certain possible ambiguities in * interpretation of certain singular times, which are resolved in the following * ways: *
* The date or time format strings are not part of the definition of a calendar, * as those must be modifiable or overridable by the user at runtime. Use * {@link java.text.DateFormat} to format dates. * *
* Field manipulation methods * *
* {@code Calendar} fields can be changed using three methods: * {@code set()}, {@code add()}, and {@code roll()}. * *
* {@code set(f, value)} changes field {@code f} * to {@code value}. In addition, it sets an internal member variable to * indicate that field {@code f} has been changed. Although field * {@code f} is changed immediately, the calendar's milliseconds is not * recomputed until the next call to {@code get()}, * {@code getTime()}, or {@code getTimeInMillis()} is made. Thus, * multiple calls to {@code set()} do not trigger multiple, unnecessary * computations. As a result of changing a field using {@code set()}, * other fields may also change, depending on the field, the field value, and * the calendar system. In addition, {@code get(f)} will not necessarily * return {@code value} after the fields have been recomputed. The * specifics are determined by the concrete calendar class. * *
* Example: Consider a {@code GregorianCalendar} originally
* set to August 31, 1999. Calling set(Calendar.MONTH,
* Calendar.SEPTEMBER)
* sets the calendar to September 31, 1999. This is a temporary internal
* representation that resolves to October 1, 1999 if {@code getTime()}is
* then called. However, a call to {@code set(Calendar.DAY_OF_MONTH, 30)}
* before the call to {@code getTime()} sets the calendar to September
* 30, 1999, since no recomputation occurs after {@code set()} itself.
*
*
* {@code add(f, delta)} adds {@code delta} to
* field {@code f}. This is equivalent to calling set(f,
* get(f) + delta)
* with two adjustments:
*
*
** ** Add rule 1. The value of field {@code f} after the * call minus the value of field {@code f} before the call is * {@code delta}, modulo any overflow that has occurred in field * {@code f}. Overflow occurs when a field value exceeds its range and, * as a result, the next larger field is incremented or decremented and the * field value is adjusted back into its range. * *
* Add rule 2. If a smaller field is expected to be invariant, * but it is impossible for it to be equal to its prior value because of * changes in its minimum or maximum after field {@code f} is changed, * then its value is adjusted to be as close as possible to its expected value. * A smaller field represents a smaller unit of time. {@code HOUR} is a * smaller field than {@code DAY_OF_MONTH}. No adjustment is made to * smaller fields that are not expected to be invariant. The calendar system * determines what fields are expected to be invariant. *
* In addition, unlike {@code set()}, {@code add()} forces an * immediate recomputation of the calendar's milliseconds and all fields. * *
* Example: Consider a {@code GregorianCalendar} originally * set to August 31, 1999. Calling {@code add(Calendar.MONTH, 13)} sets * the calendar to September 30, 2000. Add rule 1 sets the * {@code MONTH} field to September, since adding 13 months to August * gives September of the next year. Since {@code DAY_OF_MONTH} cannot be * 31 in September in a {@code GregorianCalendar}, add rule 2 * sets the {@code DAY_OF_MONTH} to 30, the closest possible value. * Although it is a smaller field, {@code DAY_OF_WEEK} is not adjusted by * rule 2, since it is expected to change when the month changes in a * {@code GregorianCalendar}. * *
* {@code roll(f, delta)} adds {@code delta} to * field {@code f} without changing larger fields. This is equivalent to * calling {@code add(f, delta)} with the following adjustment: * *
** ** Roll rule. Larger fields are unchanged after the call. A * larger field represents a larger unit of time. {@code DAY_OF_MONTH} is * a larger field than {@code HOUR}. *
* Example: Consider a {@code GregorianCalendar} originally
* set to August 31, 1999. Calling roll(Calendar.MONTH,
* 8) sets
* the calendar to April 30, 1999. Add rule 1 sets the
* {@code MONTH} field to April. Using a {@code GregorianCalendar},
* the {@code DAY_OF_MONTH} cannot be 31 in the month April. Add rule 2
* sets it to the closest possible value, 30. Finally, the roll rule
* maintains the {@code YEAR} field value of 1999.
*
*
* Example: Consider a {@code GregorianCalendar} originally * set to Sunday June 6, 1999. Calling * {@code roll(Calendar.WEEK_OF_MONTH, -1)} sets the calendar to Tuesday * June 1, 1999, whereas calling {@code add(Calendar.WEEK_OF_MONTH, -1)} * sets the calendar to Sunday May 30, 1999. This is because the roll rule * imposes an additional constraint: The {@code MONTH} must not change * when the {@code WEEK_OF_MONTH} is rolled. Taken together with add rule * 1, the resultant date must be between Tuesday June 1 and Saturday June 5. * According to add rule 2, the {@code DAY_OF_WEEK}, an invariant when * changing the {@code WEEK_OF_MONTH}, is set to Tuesday, the closest * possible value to Sunday (where Sunday is the first day of the week). * *
* Usage model. To motivate the behavior of {@code add()} * and {@code roll()}, consider a user interface component with * increment and decrement buttons for the month, day, and year, and an * underlying {@code GregorianCalendar}. If the interface reads January * 31, 1999 and the user presses the month increment button, what should it * read? If the underlying implementation uses {@code set()}, it might * read March 3, 1999. A better result would be February 28, 1999. Furthermore, * if the user presses the month increment button again, it should read March * 31, 1999, not March 28, 1999. By saving the original date and using either * {@code add()} or {@code roll()}, depending on whether larger * fields should be affected, the user interface can behave as most users will * intuitively expect. * *
* Note: You should always use {@code roll} and {@code add} rather than
* attempting to perform arithmetic operations directly on the fields of a
* Calendar. It is quite possible for Calendar subclasses
* to have fields with non-linear behavior, for example missing months or days
* during non-leap years. The subclasses' add and roll
* methods will take this into account, while simple arithmetic manipulations
* may give invalid results.
*
* @see Date
* @see GregorianCalendar
* @see TimeZone
*/
public abstract class Calendar implements Serializable, Cloneable, Comparable Note that Android does not support user-supplied locale service providers.
*/
public static synchronized Locale[] getAvailableLocales() {
return ICU.getAvailableCalendarLocales();
}
/**
* Returns the first day of the week for this {@code Calendar}.
*/
public int getFirstDayOfWeek() {
return firstDayOfWeek;
}
/**
* Returns the greatest minimum value of the given field. This is the
* biggest value that {@code getActualMinimum} can return for any possible
* time.
*/
public abstract int getGreatestMinimum(int field);
/**
* Constructs a new instance of the {@code Calendar} subclass appropriate for the
* default {@code Locale} and default {@code TimeZone}, set to the current date and time.
*/
public static synchronized Calendar getInstance() {
return new GregorianCalendar();
}
/**
* Constructs a new instance of the {@code Calendar} subclass appropriate for the
* given {@code Locale} and default {@code TimeZone}, set to the current date and time.
*/
public static synchronized Calendar getInstance(Locale locale) {
return new GregorianCalendar(locale);
}
/**
* Constructs a new instance of the {@code Calendar} subclass appropriate for the
* default {@code Locale} and given {@code TimeZone}, set to the current date and time.
*/
public static synchronized Calendar getInstance(TimeZone timezone) {
return new GregorianCalendar(timezone);
}
/**
* Constructs a new instance of the {@code Calendar} subclass appropriate for the
* given {@code Locale} and given {@code TimeZone}, set to the current date and time.
*/
public static synchronized Calendar getInstance(TimeZone timezone, Locale locale) {
return new GregorianCalendar(timezone, locale);
}
/**
* Returns the smallest maximum value of the given field. This is the
* smallest value that {@code getActualMaximum()} can return for any
* possible time.
*/
public abstract int getLeastMaximum(int field);
/**
* Returns the greatest maximum value of the given field. This returns the
* biggest value that {@code get} can return for the given field.
*/
public abstract int getMaximum(int field);
/**
* Returns the minimal days in the first week of the year.
*/
public int getMinimalDaysInFirstWeek() {
return minimalDaysInFirstWeek;
}
/**
* Returns the smallest minimum value of the given field. this returns the
* smallest value that {@code get} can return for the given field.
*/
public abstract int getMinimum(int field);
/**
* Returns the time of this {@code Calendar} as a {@code Date} object.
*
* @throws IllegalArgumentException
* if the time is not set and the time cannot be computed
* from the current field values.
*/
public final Date getTime() {
return new Date(getTimeInMillis());
}
/**
* Returns the time represented by this {@code Calendar}, recomputing the time from its
* fields if necessary.
*
* @throws IllegalArgumentException
* if the time is not set and the time cannot be computed
* from the current field values.
*/
public long getTimeInMillis() {
if (!isTimeSet) {
computeTime();
isTimeSet = true;
}
return time;
}
/**
* Returns the time zone used by this {@code Calendar}.
*/
public TimeZone getTimeZone() {
return zone;
}
@Override
public int hashCode() {
return (isLenient() ? 1237 : 1231) + getFirstDayOfWeek()
+ getMinimalDaysInFirstWeek() + getTimeZone().hashCode();
}
/**
* Returns the value of the given field without recomputing.
*/
protected final int internalGet(int field) {
return fields[field];
}
/**
* Tests whether this {@code Calendar} accepts field values which are outside the valid
* range for the field.
*/
public boolean isLenient() {
return lenient;
}
/**
* Tests whether the given field is set. Note that the interpretation of "is set" is
* somewhat technical. In particular, it does not mean that the field's value is up
* to date. If you want to know whether a field contains an up-to-date value, you must also
* check {@code areFieldsSet}, making this method somewhat useless unless you're a subclass,
* in which case you can access the {@code isSet} array directly.
*
* A field remains "set" from the first time its value is computed until it's cleared by one
* of the {@code clear} methods. Thus "set" does not mean "valid". You probably want to call
* {@code get} -- which will update fields as necessary -- rather than try to make use of
* this method.
*/
public final boolean isSet(int field) {
return isSet[field];
}
/**
* Adds the given amount to the given field and wraps the value of
* the field when it goes beyond the maximum or minimum value for the
* current date. Other fields will be adjusted as required to maintain a
* consistent date.
*/
public void roll(int field, int value) {
boolean increment = value >= 0;
int count = increment ? value : -value;
for (int i = 0; i < count; i++) {
roll(field, increment);
}
}
/**
* Increment or decrement the given field and wrap the value of the
* field when it goes beyond the maximum or minimum value for the current
* date. Other fields will be adjusted as required to maintain a consistent
* date.
*/
public abstract void roll(int field, boolean increment);
/**
* Sets the given field to the given value.
*/
public void set(int field, int value) {
fields[field] = value;
isSet[field] = true;
areFieldsSet = isTimeSet = false;
if (field > MONTH && field < AM_PM) {
lastDateFieldSet = field;
}
if (field == HOUR || field == HOUR_OF_DAY) {
lastTimeFieldSet = field;
}
if (field == AM_PM) {
lastTimeFieldSet = HOUR;
}
}
/**
* Sets the year, month, and day of the month fields.
* Other fields are not changed; call {@link #clear} first if this is not desired.
* The month value is 0-based, so it may be clearer to use a constant like {@code JANUARY}.
*/
public final void set(int year, int month, int day) {
set(YEAR, year);
set(MONTH, month);
set(DATE, day);
}
/**
* Sets the year, month, day of the month, hour of day, and minute fields.
* Other fields are not changed; call {@link #clear} first if this is not desired.
* The month value is 0-based, so it may be clearer to use a constant like {@code JANUARY}.
*/
public final void set(int year, int month, int day, int hourOfDay, int minute) {
set(year, month, day);
set(HOUR_OF_DAY, hourOfDay);
set(MINUTE, minute);
}
/**
* Sets the year, month, day of the month, hour of day, minute, and second fields.
* Other fields are not changed; call {@link #clear} first if this is not desired.
* The month value is 0-based, so it may be clearer to use a constant like {@code JANUARY}.
*/
public final void set(int year, int month, int day, int hourOfDay, int minute, int second) {
set(year, month, day, hourOfDay, minute);
set(SECOND, second);
}
/**
* Sets the first day of the week for this {@code Calendar}.
* The value should be a day of the week such as {@code MONDAY}.
*/
public void setFirstDayOfWeek(int value) {
firstDayOfWeek = value;
}
/**
* Sets whether this {@code Calendar} accepts field values which are outside the valid
* range for the field.
*/
public void setLenient(boolean value) {
lenient = value;
}
/**
* Sets the minimal days in the first week of the year.
*/
public void setMinimalDaysInFirstWeek(int value) {
minimalDaysInFirstWeek = value;
}
/**
* Sets the time of this {@code Calendar}.
*/
public final void setTime(Date date) {
setTimeInMillis(date.getTime());
}
/**
* Sets the time of this {@code Calendar} to the given Unix time. See {@link Date} for more
* about what this means.
*/
public void setTimeInMillis(long milliseconds) {
if (!isTimeSet || !areFieldsSet || time != milliseconds) {
time = milliseconds;
isTimeSet = true;
areFieldsSet = false;
complete();
}
}
/**
* Sets the {@code TimeZone} used by this Calendar.
*/
public void setTimeZone(TimeZone timezone) {
zone = timezone;
areFieldsSet = false;
}
/**
* Returns a string representation of this {@code Calendar}, showing which fields are set.
*/
@Override
public String toString() {
StringBuilder result = new StringBuilder(getClass().getName() +
"[time=" + (isTimeSet ? String.valueOf(time) : "?") +
",areFieldsSet=" + areFieldsSet +
",lenient=" + lenient +
",zone=" + zone.getID() +
",firstDayOfWeek=" + firstDayOfWeek +
",minimalDaysInFirstWeek=" + minimalDaysInFirstWeek);
for (int i = 0; i < FIELD_COUNT; i++) {
result.append(',');
result.append(FIELD_NAMES[i]);
result.append('=');
if (isSet[i]) {
result.append(fields[i]);
} else {
result.append('?');
}
}
result.append(']');
return result.toString();
}
/**
* Compares the time represented by this {@code Calendar} to that represented by the given
* {@code Calendar}.
*
* @return 0 if the times of the two {@code Calendar}s are equal, -1 if the time of
* this {@code Calendar} is before the other one, 1 if the time of this
* {@code Calendar} is after the other one.
* @throws NullPointerException
* if the argument is null.
* @throws IllegalArgumentException
* if the argument does not include a valid time
* value.
*/
public int compareTo(Calendar anotherCalendar) {
if (anotherCalendar == null) {
throw new NullPointerException("anotherCalendar == null");
}
long timeInMillis = getTimeInMillis();
long anotherTimeInMillis = anotherCalendar.getTimeInMillis();
if (timeInMillis > anotherTimeInMillis) {
return 1;
}
if (timeInMillis == anotherTimeInMillis) {
return 0;
}
return -1;
}
/**
* Returns a human-readable string for the value of {@code field}
* using the given style and locale. If no string is available, returns null.
* The value is retrieved by invoking {@code get(field)}.
*
* For example, {@code getDisplayName(MONTH, SHORT, Locale.US)} will return "Jan"
* while {@code getDisplayName(MONTH, LONG, Locale.US)} will return "January".
*
* @param field the field
* @param style {@code SHORT} or {@code LONG}
* @param locale the locale
* @return the display name, or null
* @throws NullPointerException if {@code locale == null}
* @throws IllegalArgumentException if {@code field} or {@code style} is invalid
* @since 1.6
*/
public String getDisplayName(int field, int style, Locale locale) {
// TODO: the RI's documentation says ALL_STYLES is invalid, but actually treats it as SHORT.
if (style == ALL_STYLES) {
style = SHORT;
}
String[] array = getDisplayNameArray(field, style, locale);
int value = get(field);
return (array != null) ? array[value] : null;
}
private String[] getDisplayNameArray(int field, int style, Locale locale) {
if (field < 0 || field >= FIELD_COUNT) {
throw new IllegalArgumentException("bad field " + field);
}
checkStyle(style);
DateFormatSymbols dfs = DateFormatSymbols.getInstance(locale);
switch (field) {
case AM_PM:
return dfs.getAmPmStrings();
case DAY_OF_WEEK:
return (style == LONG) ? dfs.getWeekdays() : dfs.getShortWeekdays();
case ERA:
return dfs.getEras();
case MONTH:
return (style == LONG) ? dfs.getMonths() : dfs.getShortMonths();
}
return null;
}
private static void checkStyle(int style) {
if (style != ALL_STYLES && style != SHORT && style != LONG) {
throw new IllegalArgumentException("bad style " + style);
}
}
/**
* Returns a map of human-readable strings to corresponding values,
* for the given field, style, and locale.
* Returns null if no strings are available.
*
* For example, {@code getDisplayNames(MONTH, ALL_STYLES, Locale.US)} would
* contain mappings from "Jan" and "January" to {@link #JANUARY}, and so on.
*
* @param field the field
* @param style {@code SHORT}, {@code LONG}, or {@code ALL_STYLES}
* @param locale the locale
* @return the display name, or null
* @throws NullPointerException if {@code locale == null}
* @throws IllegalArgumentException if {@code field} or {@code style} is invalid
* @since 1.6
*/
public MapDAY_OF_WEEK_IN_MONTH
* 1;
* {@code 8} through {@code 15} correspond to
* {@code DAY_OF_WEEK_IN_MONTH 2}, and so on.
* {@code DAY_OF_WEEK_IN_MONTH 0} indicates the week before
* {@code DAY_OF_WEEK_IN_MONTH 1}. Negative values count back from
* the end of the month, so the last Sunday of a month is specified as
* {@code DAY_OF_WEEK = SUNDAY, DAY_OF_WEEK_IN_MONTH = -1}. Because
* negative values count backward they will usually be aligned differently
* within the month than positive values. For example, if a month has 31
* days, {@code DAY_OF_WEEK_IN_MONTH -1} will overlap
* {@code DAY_OF_WEEK_IN_MONTH 5} and the end of {@code 4}.
*
* @see #DAY_OF_WEEK
* @see #WEEK_OF_MONTH
*/
public static final int DAY_OF_WEEK_IN_MONTH = 8;
/**
* Field number for {@code get} and {@code set} indicating
* whether the {@code HOUR} is before or after noon. E.g., at
* 10:04:15.250 PM the {@code AM_PM} is {@code PM}.
*
* @see #AM
* @see #PM
* @see #HOUR
*/
public static final int AM_PM = 9;
/**
* Field number for {@code get} and {@code set} indicating the
* hour of the morning or afternoon. {@code HOUR} is used for the
* 12-hour clock. E.g., at 10:04:15.250 PM the {@code HOUR} is 10.
*
* @see #AM_PM
* @see #HOUR_OF_DAY
*/
public static final int HOUR = 10;
/**
* Field number for {@code get} and {@code set} indicating the
* hour of the day. {@code HOUR_OF_DAY} is used for the 24-hour
* clock. E.g., at 10:04:15.250 PM the {@code HOUR_OF_DAY} is 22.
*
* @see #HOUR
*/
public static final int HOUR_OF_DAY = 11;
/**
* Field number for {@code get} and {@code set} indicating the
* minute within the hour. E.g., at 10:04:15.250 PM the {@code MINUTE}
* is 4.
*/
public static final int MINUTE = 12;
/**
* Field number for {@code get} and {@code set} indicating the
* second within the minute. E.g., at 10:04:15.250 PM the
* {@code SECOND} is 15.
*/
public static final int SECOND = 13;
/**
* Field number for {@code get} and {@code set} indicating the
* millisecond within the second. E.g., at 10:04:15.250 PM the
* {@code MILLISECOND} is 250.
*/
public static final int MILLISECOND = 14;
/**
* Field number for {@code get} and {@code set} indicating the
* raw offset from GMT in milliseconds.
*/
public static final int ZONE_OFFSET = 15;
/**
* Field number for {@code get} and {@code set} indicating the
* daylight savings offset in milliseconds.
*/
public static final int DST_OFFSET = 16;
/**
* This is the total number of fields in this calendar.
*/
public static final int FIELD_COUNT = 17;
/**
* Value of the {@code AM_PM} field indicating the period of the day
* from midnight to just before noon.
*/
public static final int AM = 0;
/**
* Value of the {@code AM_PM} field indicating the period of the day
* from noon to just before midnight.
*/
public static final int PM = 1;
/**
* Requests both {@code SHORT} and {@code LONG} styles in the map returned by
* {@link #getDisplayNames}.
* @since 1.6
*/
public static final int ALL_STYLES = 0;
/**
* Requests short names (such as "Jan") from
* {@link #getDisplayName} or {@link #getDisplayNames}.
* @since 1.6
*/
public static final int SHORT = 1;
/**
* Requests long names (such as "January") from
* {@link #getDisplayName} or {@link #getDisplayNames}.
* @since 1.6
*/
public static final int LONG = 2;
private static final String[] FIELD_NAMES = { "ERA", "YEAR", "MONTH",
"WEEK_OF_YEAR", "WEEK_OF_MONTH", "DAY_OF_MONTH", "DAY_OF_YEAR",
"DAY_OF_WEEK", "DAY_OF_WEEK_IN_MONTH", "AM_PM", "HOUR",
"HOUR_OF_DAY", "MINUTE", "SECOND", "MILLISECOND",
"ZONE_OFFSET", "DST_OFFSET" };
/**
* Constructs a {@code Calendar} instance using the default {@code TimeZone} and {@code Locale}.
*/
protected Calendar() {
this(TimeZone.getDefault(), Locale.getDefault());
}
Calendar(TimeZone timezone) {
fields = new int[FIELD_COUNT];
isSet = new boolean[FIELD_COUNT];
areFieldsSet = isTimeSet = false;
setLenient(true);
setTimeZone(timezone);
}
/**
* Constructs a {@code Calendar} instance using the given {@code TimeZone} and {@code Locale}.
*/
protected Calendar(TimeZone timezone, Locale locale) {
this(timezone);
LocaleData localeData = LocaleData.get(locale);
setFirstDayOfWeek(localeData.firstDayOfWeek.intValue());
setMinimalDaysInFirstWeek(localeData.minimalDaysInFirstWeek.intValue());
}
/**
* Adds the given amount to a {@code Calendar} field.
*
* @param field
* the {@code Calendar} field to modify.
* @param value
* the amount to add to the field.
* @throws IllegalArgumentException
* if {@code field} is {@code DST_OFFSET} or {@code
* ZONE_OFFSET}.
*/
public abstract void add(int field, int value);
/**
* Returns whether the {@code Date} represented by this {@code Calendar} instance is after the {@code Date}
* represented by the parameter. The comparison is not dependent on the time
* zones of the {@code Calendar}.
*
* @param calendar
* the {@code Calendar} instance to compare.
* @return {@code true} when this Calendar is after calendar, {@code false} otherwise.
* @throws IllegalArgumentException
* if the time is not set and the time cannot be computed
* from the current field values.
*/
public boolean after(Object calendar) {
if (!(calendar instanceof Calendar)) {
return false;
}
return getTimeInMillis() > ((Calendar) calendar).getTimeInMillis();
}
/**
* Returns whether the {@code Date} represented by this {@code Calendar} instance is before the
* {@code Date} represented by the parameter. The comparison is not dependent on the
* time zones of the {@code Calendar}.
*
* @param calendar
* the {@code Calendar} instance to compare.
* @return {@code true} when this Calendar is before calendar, {@code false} otherwise.
* @throws IllegalArgumentException
* if the time is not set and the time cannot be computed
* from the current field values.
*/
public boolean before(Object calendar) {
if (!(calendar instanceof Calendar)) {
return false;
}
return getTimeInMillis() < ((Calendar) calendar).getTimeInMillis();
}
/**
* Clears the values of all the time fields, marking them all unset and assigning
* them all a value of zero. The actual field values will be determined the next
* time the fields are accessed.
*/
public final void clear() {
for (int i = 0; i < FIELD_COUNT; i++) {
fields[i] = 0;
isSet[i] = false;
}
areFieldsSet = isTimeSet = false;
}
/**
* Clears the value in the given time field, marking it unset and assigning
* it a value of zero. The actual field value will be determined the next
* time the field is accessed.
*/
public final void clear(int field) {
fields[field] = 0;
isSet[field] = false;
areFieldsSet = isTimeSet = false;
}
/**
* Returns a shallow copy of this {@code Calendar} with the same properties.
*/
@Override
public Object clone() {
try {
Calendar clone = (Calendar) super.clone();
clone.fields = fields.clone();
clone.isSet = isSet.clone();
clone.zone = (TimeZone) zone.clone();
return clone;
} catch (CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
/**
* Computes the time from the fields if the time has not already been set.
* Computes the fields from the time if the fields are not already set.
*
* @throws IllegalArgumentException
* if the time is not set and the time cannot be computed
* from the current field values.
*/
protected void complete() {
if (!isTimeSet) {
computeTime();
isTimeSet = true;
}
if (!areFieldsSet) {
computeFields();
areFieldsSet = true;
}
}
/**
* Computes the {@code Calendar} fields from {@code time}.
*/
protected abstract void computeFields();
/**
* Computes {@code time} from the Calendar fields.
*
* @throws IllegalArgumentException
* if the time cannot be computed from the current field
* values.
*/
protected abstract void computeTime();
/**
* Compares the given object to this {@code Calendar} and returns whether they are
* equal. The object must be an instance of {@code Calendar} and have the same
* properties.
*
* @return {@code true} if the given object is equal to this {@code Calendar}, {@code false}
* otherwise.
*/
@Override
public boolean equals(Object object) {
if (this == object) {
return true;
}
if (!(object instanceof Calendar)) {
return false;
}
Calendar cal = (Calendar) object;
return getTimeInMillis() == cal.getTimeInMillis()
&& isLenient() == cal.isLenient()
&& getFirstDayOfWeek() == cal.getFirstDayOfWeek()
&& getMinimalDaysInFirstWeek() == cal.getMinimalDaysInFirstWeek()
&& getTimeZone().equals(cal.getTimeZone());
}
/**
* Returns the value of the given field after computing the field values by
* calling {@code complete()} first.
*
* @throws IllegalArgumentException
* if the fields are not set, the time is not set, and the
* time cannot be computed from the current field values.
* @throws ArrayIndexOutOfBoundsException
* if the field is not inside the range of possible fields.
* The range is starting at 0 up to {@code FIELD_COUNT}.
*/
public int get(int field) {
complete();
return fields[field];
}
/**
* Returns the maximum value of the given field for the current date.
* For example, the maximum number of days in the current month.
*/
public int getActualMaximum(int field) {
int value, next;
if (getMaximum(field) == (next = getLeastMaximum(field))) {
return next;
}
complete();
long orgTime = time;
set(field, next);
do {
value = next;
roll(field, true);
next = get(field);
} while (next > value);
time = orgTime;
areFieldsSet = false;
return value;
}
/**
* Returns the minimum value of the given field for the current date.
*/
public int getActualMinimum(int field) {
int value, next;
if (getMinimum(field) == (next = getGreatestMinimum(field))) {
return next;
}
complete();
long orgTime = time;
set(field, next);
do {
value = next;
roll(field, false);
next = get(field);
} while (next < value);
time = orgTime;
areFieldsSet = false;
return value;
}
/**
* Returns an array of locales for which custom {@code Calendar} instances
* are available.
*