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Java™ Platform
Standard Ed. 6


Class Date

java.lang.Objectextended by java.util.Date
All Implemented Interfaces:
Serializable,Cloneable,Comparable<Date>
Direct Known Subclasses:
Date,Time,Timestamp

public classDate
extendsObject
implementsSerializable,Cloneable,Comparable<Date>

The classDate represents a specific instant in time, with millisecond precision.

Prior to JDK 1.1, the classDate had two additional functions. It allowed the interpretation of dates as year, month, day, hour, minute, and second values. It also allowed the formatting and parsing of date strings. Unfortunately, the API for these functions was not amenable to internationalization. As of JDK 1.1, theCalendar class should be used to convert between dates and time fields and theDateFormat class should be used to format and parse date strings. The corresponding methods inDate are deprecated.

Although theDate class is intended to reflect coordinated universal time (UTC), it may not do so exactly, depending on the host environment of the Java Virtual Machine. Nearly all modern operating systems assume that 1 day = 24 × 60 × 60 = 86400 seconds in all cases. In UTC, however, about once every year or two there is an extra second, called a "leap second." The leap second is always added as the last second of the day, and always on December 31 or June 30. For example, the last minute of the year 1995 was 61 seconds long, thanks to an added leap second. Most computer clocks are not accurate enough to be able to reflect the leap-second distinction.

Some computer standards are defined in terms of Greenwich mean time (GMT), which is equivalent to universal time (UT). GMT is the "civil" name for the standard; UT is the "scientific" name for the same standard. The distinction between UTC and UT is that UTC is based on an atomic clock and UT is based on astronomical observations, which for all practical purposes is an invisibly fine hair to split. Because the earth's rotation is not uniform (it slows down and speeds up in complicated ways), UT does not always flow uniformly. Leap seconds are introduced as needed into UTC so as to keep UTC within 0.9 seconds of UT1, which is a version of UT with certain corrections applied. There are other time and date systems as well; for example, the time scale used by the satellite-based global positioning system (GPS) is synchronized to UTC but isnot adjusted for leap seconds. An interesting source of further information is the U.S. Naval Observatory, particularly the Directorate of Time at:

http://tycho.usno.navy.mil

and their definitions of "Systems of Time" at:

http://tycho.usno.navy.mil/systime.html

In all methods of classDate that accept or return year, month, date, hours, minutes, and seconds values, the following representations are used:

In all cases, arguments given to methods for these purposes need not fall within the indicated ranges; for example, a date may be specified as January 32 and is interpreted as meaning February 1.

Since:
JDK1.0
See Also:
DateFormat,Calendar,TimeZone,Serialized Form

Date()
          Allocates aDate object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
Date(int year, int month, int date)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date) orGregorianCalendar(year + 1900, month, date).
Date(int year, int month, int date, int hrs, int min)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min) orGregorianCalendar(year + 1900, month, date, hrs, min).
Date(int year, int month, int date, int hrs, int min, int sec)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min, sec) orGregorianCalendar(year + 1900, month, date, hrs, min, sec).
Date(long date)
          Allocates aDate object and initializes it to represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.
Date(String s)
          Deprecated. As of JDK version 1.1, replaced byDateFormat.parse(String s).
 
after(Date when)
          Tests if this date is after the specified date.
before(Date when)
          Tests if this date is before the specified date.
clone()
          Return a copy of this object.
compareTo(Date anotherDate)
          Compares two Dates for ordering.
equals(Object obj)
          Compares two dates for equality.
getDate()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.DAY_OF_MONTH).
getDay()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.DAY_OF_WEEK).
getHours()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.HOUR_OF_DAY).
getMinutes()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.MINUTE).
getMonth()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.MONTH).
getSeconds()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.SECOND).
getTime()
          Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by thisDate object.
getTimezoneOffset()
          Deprecated. As of JDK version 1.1, replaced by-(Calendar.get(Calendar.ZONE_OFFSET) + Calendar.get(Calendar.DST_OFFSET)) / (60 * 1000).
getYear()
          Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.YEAR) - 1900.
hashCode()
          Returns a hash code value for this object.
parse(String s)
          Deprecated. As of JDK version 1.1, replaced byDateFormat.parse(String s).
setDate(int date)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.DAY_OF_MONTH, int date).
setHours(int hours)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.HOUR_OF_DAY, int hours).
setMinutes(int minutes)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.MINUTE, int minutes).
setMonth(int month)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.MONTH, int month).
setSeconds(int seconds)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.SECOND, int seconds).
setTime(long time)
          Sets thisDate object to represent a point in time that istime milliseconds after January 1, 1970 00:00:00 GMT.
setYear(int year)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.YEAR, year + 1900).
toGMTString()
          Deprecated. As of JDK version 1.1, replaced byDateFormat.format(Date date), using a GMTTimeZone.
toLocaleString()
          Deprecated. As of JDK version 1.1, replaced byDateFormat.format(Date date).
toString()
          Converts thisDate object to aString of the form:
UTC(int year, int month, int date, int hrs, int min, int sec)
          Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min, sec) orGregorianCalendar(year + 1900, month, date, hrs, min, sec), using a UTCTimeZone, followed byCalendar.getTime().getTime().
 
Methods inherited from class java.lang.Object
finalize,getClass,notify,notifyAll,wait,wait,wait
 

Date

publicDate()
Allocates aDate object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.

See Also:
System.currentTimeMillis()

Date

publicDate(long date)
Allocates aDate object and initializes it to represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

Parameters:
date - the milliseconds since January 1, 1970, 00:00:00 GMT.
See Also:
System.currentTimeMillis()

Date

publicDate(int year,                       int month,                       int date)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date) orGregorianCalendar(year + 1900, month, date).

Allocates aDate object and initializes it so that it represents midnight, local time, at the beginning of the day specified by theyear,month, anddate arguments.

Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
See Also:
Calendar

Date

publicDate(int year,                       int month,                       int date,                       int hrs,                       int min)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min) orGregorianCalendar(year + 1900, month, date, hrs, min).

Allocates aDate object and initializes it so that it represents the instant at the start of the minute specified by theyear,month,date,hrs, andmin arguments, in the local time zone.

Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
hrs - the hours between 0-23.
min - the minutes between 0-59.
See Also:
Calendar

Date

publicDate(int year,                       int month,                       int date,                       int hrs,                       int min,                       int sec)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min, sec) orGregorianCalendar(year + 1900, month, date, hrs, min, sec).

Allocates aDate object and initializes it so that it represents the instant at the start of the second specified by theyear,month,date,hrs,min, andsec arguments, in the local time zone.

Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
hrs - the hours between 0-23.
min - the minutes between 0-59.
sec - the seconds between 0-59.
See Also:
Calendar

Date

publicDate(String s)
Deprecated. As of JDK version 1.1, replaced byDateFormat.parse(String s).

Allocates aDate object and initializes it so that it represents the date and time indicated by the strings, which is interpreted as if by theparse(java.lang.String) method.

Parameters:
s - a string representation of the date.
See Also:
DateFormat,parse(java.lang.String)

clone

publicObjectclone()
Return a copy of this object.

Overrides:
clone in classObject
Returns:
a clone of this instance.
See Also:
Cloneable

UTC

public static longUTC(int year,                                  int month,                                  int date,                                  int hrs,                                  int min,                                  int sec)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(year + 1900, month, date, hrs, min, sec) orGregorianCalendar(year + 1900, month, date, hrs, min, sec), using a UTCTimeZone, followed byCalendar.getTime().getTime().

Determines the date and time based on the arguments. The arguments are interpreted as a year, month, day of the month, hour of the day, minute within the hour, and second within the minute, exactly as for theDate constructor with six arguments, except that the arguments are interpreted relative to UTC rather than to the local time zone. The time indicated is returned represented as the distance, measured in milliseconds, of that time from the epoch (00:00:00 GMT on January 1, 1970).

Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
hrs - the hours between 0-23.
min - the minutes between 0-59.
sec - the seconds between 0-59.
Returns:
the number of milliseconds since January 1, 1970, 00:00:00 GMT for the date and time specified by the arguments.
See Also:
Calendar

parse

public static longparse(String s)
Deprecated. As of JDK version 1.1, replaced byDateFormat.parse(String s).

Attempts to interpret the strings as a representation of a date and time. If the attempt is successful, the time indicated is returned represented as the distance, measured in milliseconds, of that time from the epoch (00:00:00 GMT on January 1, 1970). If the attempt fails, anIllegalArgumentException is thrown.

It accepts many syntaxes; in particular, it recognizes the IETF standard date syntax: "Sat, 12 Aug 1995 13:30:00 GMT". It also understands the continental U.S. time-zone abbreviations, but for general use, a time-zone offset should be used: "Sat, 12 Aug 1995 13:30:00 GMT+0430" (4 hours, 30 minutes west of the Greenwich meridian). If no time zone is specified, the local time zone is assumed. GMT and UTC are considered equivalent.

The strings is processed from left to right, looking for data of interest. Any material ins that is within the ASCII parenthesis characters( and) is ignored. Parentheses may be nested. Otherwise, the only characters permitted withins are these ASCII characters:

 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789,+-:/
and whitespace characters.

A consecutive sequence of decimal digits is treated as a decimal number:

A consecutive sequence of letters is regarded as a word and treated as follows:

Once the entire string s has been scanned, it is converted to a time result in one of two ways. If a time zone or time-zone offset has been recognized, then the year, month, day of month, hour, minute, and second are interpreted in UTC and then the time-zone offset is applied. Otherwise, the year, month, day of month, hour, minute, and second are interpreted in the local time zone.

Parameters:
s - a string to be parsed as a date.
Returns:
the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by the string argument.
See Also:
DateFormat

getYear

public intgetYear()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.YEAR) - 1900.

Returns a value that is the result of subtracting 1900 from the year that contains or begins with the instant in time represented by thisDate object, as interpreted in the local time zone.

Returns:
the year represented by this date, minus 1900.
See Also:
Calendar

setYear

public voidsetYear(int year)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.YEAR, year + 1900).

Sets the year of thisDate object to be the specified value plus 1900. ThisDate object is modified so that it represents a point in time within the specified year, with the month, date, hour, minute, and second the same as before, as interpreted in the local time zone. (Of course, if the date was February 29, for example, and the year is set to a non-leap year, then the new date will be treated as if it were on March 1.)

Parameters:
year - the year value.
See Also:
Calendar

getMonth

public intgetMonth()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.MONTH).

Returns a number representing the month that contains or begins with the instant in time represented by thisDate object. The value returned is between0 and11, with the value0 representing January.

Returns:
the month represented by this date.
See Also:
Calendar

setMonth

public voidsetMonth(int month)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.MONTH, int month).

Sets the month of this date to the specified value. ThisDate object is modified so that it represents a point in time within the specified month, with the year, date, hour, minute, and second the same as before, as interpreted in the local time zone. If the date was October 31, for example, and the month is set to June, then the new date will be treated as if it were on July 1, because June has only 30 days.

Parameters:
month - the month value between 0-11.
See Also:
Calendar

getDate

public intgetDate()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.DAY_OF_MONTH).

Returns the day of the month represented by thisDate object. The value returned is between1 and31 representing the day of the month that contains or begins with the instant in time represented by thisDate object, as interpreted in the local time zone.

Returns:
the day of the month represented by this date.
See Also:
Calendar

setDate

public voidsetDate(int date)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.DAY_OF_MONTH, int date).

Sets the day of the month of thisDate object to the specified value. ThisDate object is modified so that it represents a point in time within the specified day of the month, with the year, month, hour, minute, and second the same as before, as interpreted in the local time zone. If the date was April 30, for example, and the date is set to 31, then it will be treated as if it were on May 1, because April has only 30 days.

Parameters:
date - the day of the month value between 1-31.
See Also:
Calendar

getDay

public intgetDay()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.DAY_OF_WEEK).

Returns the day of the week represented by this date. The returned value (0 = Sunday,1 = Monday,2 = Tuesday,3 = Wednesday,4 = Thursday,5 = Friday,6 = Saturday) represents the day of the week that contains or begins with the instant in time represented by thisDate object, as interpreted in the local time zone.

Returns:
the day of the week represented by this date.
See Also:
Calendar

getHours

public intgetHours()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.HOUR_OF_DAY).

Returns the hour represented by thisDate object. The returned value is a number (0 through23) representing the hour within the day that contains or begins with the instant in time represented by thisDate object, as interpreted in the local time zone.

Returns:
the hour represented by this date.
See Also:
Calendar

setHours

public voidsetHours(int hours)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.HOUR_OF_DAY, int hours).

Sets the hour of thisDate object to the specified value. ThisDate object is modified so that it represents a point in time within the specified hour of the day, with the year, month, date, minute, and second the same as before, as interpreted in the local time zone.

Parameters:
hours - the hour value.
See Also:
Calendar

getMinutes

public intgetMinutes()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.MINUTE).

Returns the number of minutes past the hour represented by this date, as interpreted in the local time zone. The value returned is between0 and59.

Returns:
the number of minutes past the hour represented by this date.
See Also:
Calendar

setMinutes

public voidsetMinutes(int minutes)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.MINUTE, int minutes).

Sets the minutes of thisDate object to the specified value. ThisDate object is modified so that it represents a point in time within the specified minute of the hour, with the year, month, date, hour, and second the same as before, as interpreted in the local time zone.

Parameters:
minutes - the value of the minutes.
See Also:
Calendar

getSeconds

public intgetSeconds()
Deprecated. As of JDK version 1.1, replaced byCalendar.get(Calendar.SECOND).

Returns the number of seconds past the minute represented by this date. The value returned is between0 and61. The values60 and61 can only occur on those Java Virtual Machines that take leap seconds into account.

Returns:
the number of seconds past the minute represented by this date.
See Also:
Calendar

setSeconds

public voidsetSeconds(int seconds)
Deprecated. As of JDK version 1.1, replaced byCalendar.set(Calendar.SECOND, int seconds).

Sets the seconds of thisDate to the specified value. ThisDate object is modified so that it represents a point in time within the specified second of the minute, with the year, month, date, hour, and minute the same as before, as interpreted in the local time zone.

Parameters:
seconds - the seconds value.
See Also:
Calendar

getTime

public longgetTime()
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by thisDate object.

Returns:
the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this date.

setTime

public voidsetTime(long time)
Sets thisDate object to represent a point in time that istime milliseconds after January 1, 1970 00:00:00 GMT.

Parameters:
time - the number of milliseconds.

before

public booleanbefore(Date when)
Tests if this date is before the specified date.

Parameters:
when - a date.
Returns:
true if and only if the instant of time represented by thisDate object is strictly earlier than the instant represented bywhen;false otherwise.
Throws:
NullPointerException - ifwhen is null.

after

public booleanafter(Date when)
Tests if this date is after the specified date.

Parameters:
when - a date.
Returns:
true if and only if the instant represented by thisDate object is strictly later than the instant represented bywhen;false otherwise.
Throws:
NullPointerException - ifwhen is null.

equals

public booleanequals(Object obj)
Compares two dates for equality. The result istrue if and only if the argument is notnull and is aDate object that represents the same point in time, to the millisecond, as this object.

Thus, twoDate objects are equal if and only if thegetTime method returns the samelong value for both.

Overrides:
equals in classObject
Parameters:
obj - the object to compare with.
Returns:
true if the objects are the same;false otherwise.
See Also:
getTime()

compareTo

public intcompareTo(Date anotherDate)
Compares two Dates for ordering.

Specified by:
compareTo in interfaceComparable<Date>
Parameters:
anotherDate - theDate to be compared.
Returns:
the value0 if the argument Date is equal to this Date; a value less than0 if this Date is before the Date argument; and a value greater than0 if this Date is after the Date argument.
Throws:
NullPointerException - ifanotherDate is null.
Since:
1.2

hashCode

public inthashCode()
Returns a hash code value for this object. The result is the exclusive OR of the two halves of the primitivelong value returned by thegetTime() method. That is, the hash code is the value of the expression:
 (int)(this.getTime()^(this.getTime() >>> 32))

Overrides:
hashCode in classObject
Returns:
a hash code value for this object.
See Also:
Object.equals(java.lang.Object),Hashtable

toString

publicStringtoString()
Converts thisDate object to aString of the form:
 dow mon dd hh:mm:ss zzz yyyy
where:

Overrides:
toString in classObject
Returns:
a string representation of this date.
See Also:
toLocaleString(),toGMTString()

toLocaleString

publicStringtoLocaleString()
Deprecated. As of JDK version 1.1, replaced byDateFormat.format(Date date).

Creates a string representation of thisDate object in an implementation-dependent form. The intent is that the form should be familiar to the user of the Java application, wherever it may happen to be running. The intent is comparable to that of the "%c" format supported by thestrftime() function of ISO C.

Returns:
a string representation of this date, using the locale conventions.
See Also:
DateFormat,toString(),toGMTString()

toGMTString

publicStringtoGMTString()
Deprecated. As of JDK version 1.1, replaced byDateFormat.format(Date date), using a GMTTimeZone.

Creates a string representation of thisDate object of the form: d mon yyyy hh:mm:ss GMT where:
  • d is the day of the month (1 through31), as one or two decimal digits.
  • mon is the month (Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec).
  • yyyy is the year, as four decimal digits.
  • hh is the hour of the day (00 through23), as two decimal digits.
  • mm is the minute within the hour (00 through59), as two decimal digits.
  • ss is the second within the minute (00 through61), as two decimal digits.
  • GMT is exactly the ASCII letters "GMT" to indicate Greenwich Mean Time.

The result does not depend on the local time zone.

Returns:
a string representation of this date, using the Internet GMT conventions.
See Also:
DateFormat,toString(),toLocaleString()

getTimezoneOffset

public intgetTimezoneOffset()
Deprecated. As of JDK version 1.1, replaced by-(Calendar.get(Calendar.ZONE_OFFSET) + Calendar.get(Calendar.DST_OFFSET)) / (60 * 1000).

Returns the offset, measured in minutes, for the local time zone relative to UTC that is appropriate for the time represented by thisDate object.

For example, in Massachusetts, five time zones west of Greenwich:

 new Date(96, 1, 14).getTimezoneOffset() returns 300
because on February 14, 1996, standard time (Eastern Standard Time) is in use, which is offset five hours from UTC; but:
 new Date(96, 5, 1).getTimezoneOffset() returns 240
because on June 1, 1996, daylight saving time (Eastern Daylight Time) is in use, which is offset only four hours from UTC.

This method produces the same result as if it computed:

 (this.getTime() - UTC(this.getYear(),                        this.getMonth(),                        this.getDate(),                       this.getHours(),                        this.getMinutes(),                        this.getSeconds())) / (60 * 1000)

Returns:
the time-zone offset, in minutes, for the current time zone.
See Also:
Calendar.ZONE_OFFSET,Calendar.DST_OFFSET,TimeZone.getDefault()

          
Java™ Platform
Standard Ed. 6


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