Class Calendar

java.lang.Object
java.util.Calendar
public abstract class Calendar extends Object
Calendar is an abstract base class for converting between a Date object and a set of integer fields such as YEAR, MONTH, DAY, HOUR, and so on. (A Date object represents a specific instant in time with millisecond precision. See Date for information about the Date class.) Subclasses of Calendar interpret a Date according to the rules of a specific calendar system. Like other locale-sensitive classes, Calendar provides a class method, getInstance, for getting a generally useful object of this type. A 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). When computing a Date from time fields, there may be insufficient information to compute the Date (such as only year and month but no day in the month). 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. Note: The ambiguity in interpretation of what day midnight belongs to, is resolved as so: midnight "belongs" to the following day. 23:59 on Dec 31, 1969 00:00 on Jan 1, 1970. 12:00 PM is midday, and 12:00 AM is midnight. 11:59 PM on Jan 1 12:00 AM on Jan 2 12:01 AM on Jan 2. 11:59 AM on Mar 10 12:00 PM on Mar 10 12:01 PM on Mar 10. 24:00 or greater are invalid. Hours greater than 12 are invalid in AM/PM mode. Setting the time will never change the date. If equivalent times are entered in AM/PM or 24 hour mode, equality will be determined by the actual time rather than the entered time. This class has been subset for J2ME based on the JDK 1.3 Calendar class. Many methods and variables have been pruned, and other methods simplified, in an effort to reduce the size of this class. Version: CLDC 1.1 02/01/2002 (based on JDK 1.3) See Also:Date, TimeZone

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    AM
    Value of the AM_PM field indicating the period of the day from midnight to just before noon.
    static final int
    AM_PM
    Field number for get and set indicating whether the HOUR is before or after noon.
    static final int
    APRIL
    Value of the MONTH field indicating the fourth month of the year.
    static final int
    AUGUST
    Value of the MONTH field indicating the eighth month of the year.
    static final int
    DATE
    Field number for get and set indicating the day of the month.
    static final int
    DAY_OF_MONTH
    Field number for get and set indicating the day of the month.
    static final int
    DAY_OF_WEEK
    Field number for get and set indicating the day of the week.
    static final int
    DAY_OF_WEEK_IN_MONTH
    Field number for get and set indicating the ordinal number of the day of the week within the current month.
    static final int
    DECEMBER
    Value of the MONTH field indicating the twelfth month of the year.
    static final int
    FEBRUARY
    Value of the MONTH field indicating the second month of the year.
    protected int[]
    fields
    The field values for the currently set time for this calendar.
    static final int
    FRIDAY
    Value of the DAY_OF_WEEK field indicating Friday.
    static final int
    HOUR
    Field number for get and set indicating the hour of the morning or afternoon.
    static final int
    HOUR_OF_DAY
    Field number for get and set indicating the hour of the day.
    protected boolean[]
    isSet
    The flags which tell if a specified time field for the calendar is set.
    static final int
    JANUARY
    Value of the MONTH field indicating the first month of the year.
    static final int
    JULY
    Value of the MONTH field indicating the seventh month of the year.
    static final int
    JUNE
    Value of the MONTH field indicating the sixth month of the year.
    static final int
    MARCH
    Value of the MONTH field indicating the third month of the year.
    static final int
    MAY
    Value of the MONTH field indicating the fifth month of the year.
    static final int
    MILLISECOND
    Field number for get and set indicating the millisecond within the second.
    static final int
    MINUTE
    Field number for get and set indicating the minute within the hour.
    static final int
    MONDAY
    Value of the DAY_OF_WEEK field indicating Monday.
    static final int
    MONTH
    Field number for get and set indicating the month.
    static final int
    NOVEMBER
    Value of the MONTH field indicating the eleventh month of the year.
    static final int
    OCTOBER
    Value of the MONTH field indicating the tenth month of the year.
    static final int
    PM
    Value of the AM_PM field indicating the period of the day from noon to just before midnight.
    static final int
    SATURDAY
    Value of the DAY_OF_WEEK field indicating Saturday.
    static final int
    SECOND
    Field number for get and set indicating the second within the minute.
    static final int
    SEPTEMBER
    Value of the MONTH field indicating the ninth month of the year.
    static final int
    SUNDAY
    Value of the DAY_OF_WEEK field indicating Sunday.
    static final int
    THURSDAY
    Value of the DAY_OF_WEEK field indicating Thursday.
    protected long
    time
    The currently set time for this calendar, expressed in milliseconds after January 1, 1970, 0:00:00 GMT.
    static final int
    TUESDAY
    Value of the DAY_OF_WEEK field indicating Tuesday.
    static final int
    WEDNESDAY
    Value of the DAY_OF_WEEK field indicating Wednesday.
    static final int
    WEEK_OF_MONTH
    Field number for get and set indicating the week number within the current month.
    static final int
    WEEK_OF_YEAR
    Field number for get and set indicating the week number within the current year.
    static final int
    YEAR
    Field number for get and set indicating the year.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    Calendar()
    Constructs a Calendar with the default time zone.

  • Method Summary

    Modifier and Type
    Method
    Description
    final void
    add(int field, int value)
    Adds the specified amount to a Calendar field.
    boolean
    after(Object when)
    Compares the time field records.
    boolean
    before(Object when)
    Compares the time field records.
    protected abstract void
    computeFields()
    Converts the current millisecond time value time to field values in fields[].
    protected abstract void
    computeTime()
    Converts the current field values in fields[] to the millisecond time value time.
    boolean
    equals(Object obj)
    Compares this calendar to the specified object.
    final int
    get(int field)
    Gets the value for a given time field.
    static Calendar
    getInstance()
    Gets a calendar using the default time zone.
    static Calendar
    getInstance(TimeZone zone)
    Gets a calendar using the specified time zone.
    final Date
    getTime()
    Gets this Calendar's current time.
    protected long
    getTimeInMillis()
    Gets this Calendar's current time as a long expressed in milliseconds after January 1, 1970, 0:00:00 GMT (the epoch).
    TimeZone
    getTimeZone()
    Gets the time zone.
    final void
    set(int field, int value)
    Sets the time field with the given value.
    final void
    setTime(Date date)
    Sets this Calendar's current time with the given Date.
    protected void
    setTimeInMillis(long millis)
    Sets this Calendar's current time from the given long value.
    void
    setTimeZone(TimeZone value)
    Sets the time zone with the given time zone value.

    Methods inherited from class Object

    clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • AM

      public static final int AM
      Value of the AM_PM field indicating the period of the day from midnight to just before noon. See Also:Constant Field Values
      See Also:

    • AM_PM

      public static final int AM_PM
      Field number for get and set indicating whether the HOUR is before or after noon. E.g., at 10:04:15.250 PM the AM_PM is PM. See Also:AM, PM, HOUR, Constant Field Values
      See Also:

    • APRIL

      public static final int APRIL
      Value of the MONTH field indicating the fourth month of the year. See Also:Constant Field Values
      See Also:

    • AUGUST

      public static final int AUGUST
      Value of the MONTH field indicating the eighth month of the year. See Also:Constant Field Values
      See Also:

    • WEEK_OF_YEAR

      public static final int WEEK_OF_YEAR
      Field number for get and set indicating the week number within the current year. The first week of the year, as defined by getFirstDayOfWeek() and getMinimalDaysInFirstWeek(), has value 1. Subclasses define the value of WEEK_OF_YEAR for days before the first week of the year.
      See Also:
      • invalid reference 
        #getFirstDayOfWeek
      • invalid reference 
        #getMinimalDaysInFirstWeek
      • Constant Field Values

    • WEEK_OF_MONTH

      public static final int WEEK_OF_MONTH
      Field number for get and set indicating the week number within the current month. The first week of the month, as defined by getFirstDayOfWeek() and getMinimalDaysInFirstWeek(), has value 1. Subclasses define the value of WEEK_OF_MONTH for days before the first week of the month.
      See Also:
      • invalid reference 
        #getFirstDayOfWeek
      • invalid reference 
        #getMinimalDaysInFirstWeek
      • Constant Field Values

    • DATE

      public static final int DATE
      Field number for get and set indicating the day of the month. This is a synonym for DAY_OF_MONTH. See Also:DAY_OF_MONTH, Constant Field Values
      See Also:

    • DAY_OF_MONTH

      public static final int DAY_OF_MONTH
      Field number for get and set indicating the day of the month. This is a synonym for DATE. See Also:DATE, Constant Field Values
      See Also:

    • DAY_OF_WEEK

      public static final int DAY_OF_WEEK
      Field number for get and set indicating the day of the week. See Also:Constant Field Values
      See Also:

    • DAY_OF_WEEK_IN_MONTH

      public static final int DAY_OF_WEEK_IN_MONTH
      Field number for get and set indicating the ordinal number of the day of the week within the current month. Together with the DAY_OF_WEEK field, this uniquely specifies a day within a month. Unlike WEEK_OF_MONTH and WEEK_OF_YEAR, this field's value does not depend on getFirstDayOfWeek() or getMinimalDaysInFirstWeek(). DAY_OF_MONTH 1 through 7 always correspond to DAY_OF_WEEK_IN_MONTH 1; 8 through 15 correspond to DAY_OF_WEEK_IN_MONTH 2, and so on. DAY_OF_WEEK_IN_MONTH 0 indicates the week before 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 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, DAY_OF_WEEK_IN_MONTH -1 will overlap DAY_OF_WEEK_IN_MONTH 5 and the end of 4.
      See Also:

    • DECEMBER

      public static final int DECEMBER
      Value of the MONTH field indicating the twelfth month of the year. See Also:Constant Field Values
      See Also:

    • FEBRUARY

      public static final int FEBRUARY
      Value of the MONTH field indicating the second month of the year. See Also:Constant Field Values
      See Also:

    • fields

      protected int[] fields
      The field values for the currently set time for this calendar.

    • FRIDAY

      public static final int FRIDAY
      Value of the DAY_OF_WEEK field indicating Friday. See Also:Constant Field Values
      See Also:

    • HOUR

      public static final int HOUR
      Field number for get and set indicating the hour of the morning or afternoon. HOUR is used for the 12-hour clock. E.g., at 10:04:15.250 PM the HOUR is 10. See Also:AM_PM, HOUR_OF_DAY, Constant Field Values
      See Also:

    • HOUR_OF_DAY

      public static final int HOUR_OF_DAY
      Field number for get and set indicating the hour of the day. HOUR_OF_DAY is used for the 24-hour clock. E.g., at 10:04:15.250 PM the HOUR_OF_DAY is 22. See Also:Constant Field Values
      See Also:

    • isSet

      protected boolean[] isSet
      The flags which tell if a specified time field for the calendar is set. This is an array of FIELD_COUNT booleans,

    • JANUARY

      public static final int JANUARY
      Value of the MONTH field indicating the first month of the year. See Also:Constant Field Values
      See Also:

    • JULY

      public static final int JULY
      Value of the MONTH field indicating the seventh month of the year. See Also:Constant Field Values
      See Also:

    • JUNE

      public static final int JUNE
      Value of the MONTH field indicating the sixth month of the year. See Also:Constant Field Values
      See Also:

    • MARCH

      public static final int MARCH
      Value of the MONTH field indicating the third month of the year. See Also:Constant Field Values
      See Also:

    • MAY

      public static final int MAY
      Value of the MONTH field indicating the fifth month of the year. See Also:Constant Field Values
      See Also:

    • MILLISECOND

      public static final int MILLISECOND
      Field number for get and set indicating the millisecond within the second. E.g., at 10:04:15.250 PM the MILLISECOND is 250. See Also:Constant Field Values
      See Also:

    • MINUTE

      public static final int MINUTE
      Field number for get and set indicating the minute within the hour. E.g., at 10:04:15.250 PM the MINUTE is 4. See Also:Constant Field Values
      See Also:

    • MONDAY

      public static final int MONDAY
      Value of the DAY_OF_WEEK field indicating Monday. See Also:Constant Field Values
      See Also:

    • MONTH

      public static final int MONTH
      Field number for get and set indicating the month. This is a calendar-specific value. See Also:Constant Field Values
      See Also:

    • NOVEMBER

      public static final int NOVEMBER
      Value of the MONTH field indicating the eleventh month of the year. See Also:Constant Field Values
      See Also:

    • OCTOBER

      public static final int OCTOBER
      Value of the MONTH field indicating the tenth month of the year. See Also:Constant Field Values
      See Also:

    • PM

      public static final int PM
      Value of the AM_PM field indicating the period of the day from noon to just before midnight. See Also:Constant Field Values
      See Also:

    • SATURDAY

      public static final int SATURDAY
      Value of the DAY_OF_WEEK field indicating Saturday. See Also:Constant Field Values
      See Also:

    • SECOND

      public static final int SECOND
      Field number for get and set indicating the second within the minute. E.g., at 10:04:15.250 PM the SECOND is 15. See Also:Constant Field Values
      See Also:

    • SEPTEMBER

      public static final int SEPTEMBER
      Value of the MONTH field indicating the ninth month of the year. See Also:Constant Field Values
      See Also:

    • SUNDAY

      public static final int SUNDAY
      Value of the DAY_OF_WEEK field indicating Sunday. See Also:Constant Field Values
      See Also:

    • THURSDAY

      public static final int THURSDAY
      Value of the DAY_OF_WEEK field indicating Thursday. See Also:Constant Field Values
      See Also:

    • time

      protected long time
      The currently set time for this calendar, expressed in milliseconds after January 1, 1970, 0:00:00 GMT.

    • TUESDAY

      public static final int TUESDAY
      Value of the DAY_OF_WEEK field indicating Tuesday. See Also:Constant Field Values
      See Also:

    • WEDNESDAY

      public static final int WEDNESDAY
      Value of the DAY_OF_WEEK field indicating Wednesday. See Also:Constant Field Values
      See Also:

    • YEAR

      public static final int YEAR
      Field number for get and set indicating the year. This is a calendar-specific value. See Also:Constant Field Values
      See Also:

  • Constructor Details

    • Calendar

      protected Calendar()
      Constructs a Calendar with the default time zone. See Also:TimeZone.getDefault()

  • Method Details

    • after

      public boolean after(Object when)
      Compares the time field records. Equivalent to comparing result of conversion to UTC.

    • before

      public boolean before(Object when)
      Compares the time field records. Equivalent to comparing result of conversion to UTC.

    • computeFields

      protected abstract void computeFields()
      Converts the current millisecond time value time to field values in fields[]. This allows you to sync up the time field values with a new time that is set for the calendar.

    • computeTime

      protected abstract void computeTime()
      Converts the current field values in fields[] to the millisecond time value time.

    • equals

      public boolean equals(Object obj)
      Compares this calendar to the specified object. The result is true if and only if the argument is not null and is a Calendar object that represents the same calendar as this object.
      Overrides:
      equals in class Object

    • get

      public final int get(int field)
      Gets the value for a given time field.

    • getInstance

      public static Calendar getInstance()
      Gets a calendar using the default time zone.

    • getInstance

      public static Calendar getInstance(TimeZone zone)
      Gets a calendar using the specified time zone.

    • getTime

      public final Date getTime()
      Gets this Calendar's current time.

    • getTimeInMillis

      protected long getTimeInMillis()
      Gets this Calendar's current time as a long expressed in milliseconds after January 1, 1970, 0:00:00 GMT (the epoch).

    • getTimeZone

      public TimeZone getTimeZone()
      Gets the time zone.

    • set

      public final void set(int field, int value)
      Sets the time field with the given value.

    • add

      public final void add(int field, int value)
      Adds the specified amount to a Calendar field.
      Parameters:
      field - the Calendar field to modify.
      value - the amount to add to the field.
      Throws:
      IllegalArgumentException - if field is DST_OFFSET or ZONE_OFFSET.

    • setTime

      public final void setTime(Date date)
      Sets this Calendar's current time with the given Date. Note: Calling setTime() with Date(Long.MAX_VALUE) or Date(Long.MIN_VALUE) may yield incorrect field values from get().

    • setTimeInMillis

      protected void setTimeInMillis(long millis)
      Sets this Calendar's current time from the given long value.

    • setTimeZone

      public void setTimeZone(TimeZone value)
      Sets the time zone with the given time zone value.