java.util

Class Date

java.lang.Object

java.util.Date

All Implemented Interfaces:

Cloneable

public class Date
extends Object
implements Cloneable

Constructor Summary

Constructors

Constructor and Description
Date() Allocates a Date 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) Allocates a Date object and initializes it so that it represents midnight, local time, at the beginning of the day specified by the year, month, and date arguments.
Date(int year, int month, int date, int hrs, int min) Allocates a Date object and initializes it so that it represents the instant at the start of the minute specified by the year, month, date, hrs, and min arguments, in the local time zone.
Date(int year, int month, int date, int hrs, int min, int sec) Allocates a Date object and initializes it so that it represents the instant at the start of the second specified by the year, month, date, hrs, min, and sec arguments, in the local time zone.
Date(long time) Allocates a Date 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 datestr) Allocates a Date object and initializes it so that it represents the date and time indicated by the string s, which is interpreted as if by the parse(java.lang.String) method.

Method Summary

Modifier and Type	Method and Description
boolean	after(Date when) Tests if this date is after the specified date.
boolean	before(Date when) Tests if this date is before the specified date.
boolean	equals(Object obj) Compares two dates for equality.
int	getDate() Returns the day of the month represented by this Date object.
int	getDay() Returns the day of the week represented by this date.
int	getHours() Returns the hour represented by this Date object.
int	getMinutes() Returns the number of minutes past the hour represented by this date, as interpreted in the local time zone.
int	getMonth() Returns a number representing the month that contains or begins with the instant in time represented by this Date object.
int	getSeconds() Returns the number of seconds past the minute represented by this date.
long	getTime() Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.
int	getTimezoneOffset() Returns the offset, measured in minutes, for the local time zone relative to UTC that is appropriate for the time represented by this Date object.
int	getYear() Returns a value that is the result of subtracting 1900 from the year that contains or begins with the instant in time represented by this Date object, as interpreted in the local time zone.
int	hashCode() Returns a hash code value for this object.
static long	parse(String datestr) Attempts to interpret the string s as a representation of a date and time.
void	setDate(int date) Sets the day of the month of this Date object to the specified value.
void	setHours(int hours) Sets the hour of this Date object to the specified value.
void	setMinutes(int minutes) Sets the minutes of this Date object to the specified value.
void	setMonth(int month) Sets the month of this date to the specified value.
void	setSeconds(int seconds) Sets the seconds of this Date to the specified value.
void	setTime(long time) Sets this Date object to represent a point in time that is time mitimetimeiseconds after January 1, 1970 00:00:00 GMT.
void	setYear(int year) Sets the year of this Date object to be the specified value plus 1900.
String	toGMTString() Creates a string representation of this Date object of the form:
String	toLocaleString() Creates a string representation of this Date object in an implementation-dependent form.
String	toString() Converts this Date object to a String of the form:
static long	UTC(int year, int month, int date, int hrs, int min, int sec) Determines the date and time based on the arguments.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Date

public Date()

Allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.

See Also:

Timebase.currentTimeMillis()

Date

public Date(int year,
            int month,
            int date)

Allocates a Date object and initializes it so that it represents midnight, local time, at the beginning of the day specified by the year, month, and date arguments.

Parameters:

year - the year minus 1900.

month - the month between 0-11.

date - the day of the month between 1-31.

See Also:

replaced by Calendar.set(year + 1900, month, date) or GregorianCalendar(year + 1900, month, date).

Date

public Date(int year,
            int month,
            int date,
            int hrs,
            int min)

Allocates a Date object and initializes it so that it represents the instant at the start of the minute specified by the year, month, date, hrs, and min 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

public Date(int year,
            int month,
            int date,
            int hrs,
            int min,
            int sec)

Allocates a Date object and initializes it so that it represents the instant at the start of the second specified by the year, month, date, hrs, min, and sec 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

public Date(long time)

Allocates a Date 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:

time - the milliseconds since January 1, 1970, 00:00:00 GMT.

See Also:

System.currentTimeMillis()

Date

public Date(String datestr)
     throws IllegalArgumentException

Allocates a Date object and initializes it so that it represents the date and time indicated by the string s, which is interpreted as if by the parse(java.lang.String) method.

Parameters:

datestr - a string representation of the date.

Throws:

IllegalArgumentException

See Also:

DateFormat, parse(java.lang.String)

Method Detail

UTC

public static long UTC(int year,
                       int month,
                       int date,
                       int hrs,
                       int min,
                       int sec)

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 the Date 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.

after

public boolean after(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 this Date object is strictly later than the instant represented by when; false otherwise.

Throws:

NullPointerException - if when is null.

before

public boolean before(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 this Date object is strictly earlier than the instant represented by when; false otherwise.

Throws:

NullPointerException - if when is null.

equals

public boolean equals(Object obj)

Compares two dates for equality. The result is true if and only if the argument is not null and is a Date object that represents the same point in time, to the millisecond, as this object.

Thus, two Date objects are equal if and only if the getTime method returns the same long value for both.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.

See Also:

getTime()

getDate

public int getDate()

Returns the day of the month represented by this Date object. The value returned is between 1 and 31 representing the day of the month that contains or begins with the instant in time represented by this Date object, as interpreted in the local time zone.

Returns:

the day of the month represented by this date.

See Also:

Calendar

getDay

public int getDay()

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 this Date object, as interpreted in the local time zone.

Returns:

the day of the week represented by this date.

See Also:

Calendar

getHours

public int getHours()

Returns the hour represented by this Date object. The returned value is a number (0 through 23) representing the hour within the day that contains or begins with the instant in time represented by this Date object, as interpreted in the local time zone.

Returns:

the hour represented by this date.

See Also:

Calendar

getMinutes

public int getMinutes()

Returns the number of minutes past the hour represented by this date, as interpreted in the local time zone. The value returned is between 0 and 59.

Returns:

the number of minutes past the hour represented by this date.

See Also:

Calendar

getMonth

public int getMonth()

Returns a number representing the month that contains or begins with the instant in time represented by this Date object. The value returned is between 0 and 11, with the value 0 representing January.

Returns:

the month represented by this date.

See Also:

Calendar

getSeconds

public int getSeconds()

Returns the number of seconds past the minute represented by this date. The value returned is between 0 and 61. The values 60 and 61 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

getTime

public long getTime()

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

Returns:

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

getTimezoneOffset

public int getTimezoneOffset()

Returns the offset, measured in minutes, for the local time zone relative to UTC that is appropriate for the time represented by this Date 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()

getYear

public int getYear()

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

Returns:

the year represented by this date, minus 1900.

See Also:

Calendar

hashCode

public int hashCode()

Returns a hash code value for this object. The result is the exclusive OR of the two halves of the primitive long value returned by the getTime() method. That is, the hash code is the value of the expression:

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

parse

public static long parse(String datestr)

Attempts to interpret the string s 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, an IllegalArgumentException 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 string s is processed from left to right, looking for data of interest. Any material in s that is within the ASCII parenthesis characters ( and ) is ignored. Parentheses may be nested. Otherwise, the only characters permitted within s are these ASCII characters:

 abcdefghijklmnopqrstuvwxyz
 ABCDEFGHIJKLMNOPQRSTUVWXYZ
 0123456789,+-:/

and whitespace characters.

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

• If a number is preceded by + or - and a year has already been recognized, then the number is a time-zone offset. If the number is less than 24, it is an offset measured in hours. Otherwise, it is regarded as an offset in minutes, expressed in 24-hour time format without punctuation. A preceding - means a westward offset. Time zone offsets are always relative to UTC (Greenwich). Thus, for example, -5 occurring in the string would mean "five hours west of Greenwich" and +0430 would mean "four hours and thirty minutes east of Greenwich." It is permitted for the string to specify GMT, UT, or UTC redundantly-for example, GMT-5 or utc+0430.
• The number is regarded as a year number if one of the following conditions is true:
  • The number is equal to or greater than 70 and followed by a space, comma, slash, or end of string
  • The number is less than 70, and both a month and a day of the month have already been recognized
  If the recognized year number is less than 100, it is interpreted as an abbreviated year relative to a century of which dates are within 80 years before and 19 years after the time when the Date class is initialized. After adjusting the year number, 1900 is subtracted from it. For example, if the current year is 1999 then years in the range 19 to 99 are assumed to mean 1919 to 1999, while years from 0 to 18 are assumed to mean 2000 to 2018. Note that this is slightly different from the interpretation of years less than 100 that is used in SimpleDateFormat.
• If the number is followed by a colon, it is regarded as an hour, unless an hour has already been recognized, in which case it is regarded as a minute.
• If the number is followed by a slash, it is regarded as a month (it is decreased by 1 to produce a number in the range 0 to 11), unless a month has already been recognized, in which case it is regarded as a day of the month.
• If the number is followed by whitespace, a comma, a hyphen, or end of string, then if an hour has been recognized but not a minute, it is regarded as a minute; otherwise, if a minute has been recognized but not a second, it is regarded as a second; otherwise, it is regarded as a day of the month.

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

• A word that matches AM, ignoring case, is ignored (but the parse fails if an hour has not been recognized or is less than 1 or greater than 12).
• A word that matches PM, ignoring case, adds 12 to the hour (but the parse fails if an hour has not been recognized or is less than 1 or greater than 12).
• Any word that matches any prefix of SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, or SATURDAY, ignoring case, is ignored. For example, sat, Friday, TUE, and Thurs are ignored.
• Otherwise, any word that matches any prefix of JANUARY, FEBRUARY, MARCH, APRIL, MAY, JUNE, JULY, AUGUST, SEPTEMBER, OCTOBER, NOVEMBER, or DECEMBER, ignoring case, and considering them in the order given here, is recognized as specifying a month and is converted to a number (0 to 11). For example, aug, Sept, april, and NOV are recognized as months. So is Ma, which is recognized as MARCH, not MAY.
• Any word that matches GMT, UT, or UTC, ignoring case, is treated as referring to UTC.
• Any word that matches EST, CST, MST, or PST, ignoring case, is recognized as referring to the time zone in North America that is five, six, seven, or eight hours west of Greenwich, respectively. Any word that matches EDT, CDT, MDT, or PDT, ignoring case, is recognized as referring to the same time zone, respectively, during daylight saving time.

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:

datestr - 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

setDate

public void setDate(int date)

Sets the day of the month of this Date object to the specified value. This Date 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

setHours

public void setHours(int hours)

Sets the hour of this Date object to the specified value. This Date 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

setMinutes

public void setMinutes(int minutes)

Sets the minutes of this Date object to the specified value. This Date 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

setMonth

public void setMonth(int month)

Sets the month of this date to the specified value. This Date 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

setSeconds

public void setSeconds(int seconds)

Sets the seconds of this Date to the specified value. This Date 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

setTime

public void setTime(long time)

Sets this Date object to represent a point in time that is time mitimetimeiseconds after January 1, 1970 00:00:00 GMT.

Parameters:

time - the number of milliseconds.

setYear

public void setYear(int year)

Sets the year of this Date object to be the specified value plus 1900. This Date 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

toGMTString

public String toGMTString()

Creates a string representation of this Date object of the form:

 d mon yyyy hh:mm:ss GMT

where:

• d is the day of the month (1 through 31), 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 through 23), as two decimal digits.
• mm is the minute within the hour (00 through 59), as two decimal digits.
• ss is the second within the minute (00 through 61), 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(), TimeZone.

toLocaleString

public String toLocaleString()

Creates a string representation of this Date 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 the strftime() function of ISO C.

Returns:

a string representation of this date, using the locale conventions.

See Also:

DateFormat, toString(), toGMTString()

toString

public String toString()

Converts this Date object to a String of the form:

 dow mon dd hh:mm:ss zzz yyyy

where:

• dow is the day of the week (Sun, Mon, Tue, Wed, Thu, Fri, Sat).
• mon is the month (Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec).
• dd is the day of the month (01 through 31), as two decimal digits.
• hh is the hour of the day (00 through 23), as two decimal digits.
• mm is the minute within the hour (00 through 59), as two decimal digits.
• ss is the second within the minute (00 through 61, as two decimal digits.
• zzz is the time zone (and may reflect daylight saving time). Standard time zone abbreviations include those recognized by the method parse. If time zone information is not available, then zzz is empty - that is, it consists of no characters at all.
• yyyy is the year, as four decimal digits.

Overrides:

toString in class Object

Returns:

a string representation of this date.

See Also:

toLocaleString(), toGMTString()