All Packages Class Hierarchy This Package Previous Next Index
java.lang.Object | +----java.util.Date
Date object represents a specific instant in time with
millisecond precision.
Date 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, the Calendar
class should be used to convert between dates and time fields and the
DateFormat class should be used to format and parse date
strings. The corresponding methods in Date are deprecated.
While the API is intended to reflect UTC, Coordinated Universal Time, it doesn't do so exactly. This inexact behavior is inherited from the time system of the underlying OS. All modern OS's that I (jag) am aware of assume that 1 day = 24*60*60 seconds. In UTC, about once a year there is an extra second, called a "leap second" added to a day to account for the wobble of the earth. Most computer clocks are not accurate enough to be able to reflect this distinction. Some computer standards are defined in GMT, which is equivalent to UT, Universal Time. 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 the first is based on an atomic clock and the second is based on astronomical observations, which for all practical purposes is an invisibly fine hair to split. An interesting source of further information is the US Naval Observatory, particularly the Directorate of Time and their definitions of Systems of Time.
Date()
Date object and initializes it so that
it represents the time at which it was allocated measured to the
nearest millisecond.
Date(int, int, int)
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.
Deprecated.
Date(int, int, int, int, int)
Date object and initializes it so that
it represents the specified hour and minute, local time, of the
date specified by the year, month,
date, hrs, and min arguments.
Deprecated.
Date(int, int, int, int, int, int)
Date object and initializes it so that
it represents the specified hour, minute, and second, local time
of the date specified by the year, month,
date, hrs, min, and
sec arguments.
Deprecated.
Date(long)
Date object and initializes it to
represent the specified number of milliseconds since January 1,
1970, 00:00:00 GMT.
Date(String)
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 method.
Deprecated.
after(Date)
before(Date)
equals(Object)
getDate()
getDay()
getHours()
getMinutes()
getMonth()
getSeconds()
getTime()
getTimezoneOffset()
getYear()
hashCode()
parse(String)
setDate(int)
setHours(int)
setMinutes(int)
setMonth(int)
setSeconds(int)
setTime(long)
setYear(int)
toGMTString()
toLocaleString()
toString()
UTC(int, int, int, int, int, int)
Date
public Date()
Date object and initializes it so that
it represents the time at which it was allocated measured to the
nearest millisecond.
Date
public Date(long date)
Date object and initializes it to
represent the specified number of milliseconds since January 1,
1970, 00:00:00 GMT.
Date
public Date(int year,
int month,
int date)
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
public Date(int year,
int month,
int date,
int hrs,
int min)
Date object and initializes it so that
it represents the specified hour and minute, local time, of the
date specified by the year, month,
date, hrs, and min arguments.
Date
public Date(int year,
int month,
int date,
int hrs,
int min,
int sec)
Date object and initializes it so that
it represents the specified hour, minute, and second, local time
of the date specified by the year, month,
date, hrs, min, and
sec arguments.
Date
public Date(String s)
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 method.
UTC
public static long UTC(int year,
int month,
int date,
int hrs,
int min,
int sec)
parse
public static long parse(String s)
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.
getYear
public int getYear()
setYear
public void setYear(int year)
getMonth
public int getMonth()
0 and 11, with the value
0 representing January.
setMonth
public void setMonth(int month)
getDate
public int getDate()
1 and 31.
setDate
public void setDate(int date)
getDay
public int getDay()
0 and 6, where 0
represents Sunday.
getHours
public int getHours()
0 and 23, where 0 represents
midnight.
setHours
public void setHours(int hours)
getMinutes
public int getMinutes()
0 and 59.
setMinutes
public void setMinutes(int minutes)
getSeconds
public int getSeconds()
0 and 60. The
value 60 can only occur on those Java Virtual Machines that
take leap seconds into account.
setSeconds
public void setSeconds(int seconds)
getTime
public long getTime()
setTime
public void setTime(long time)
before
public boolean before(Date when)
true if this date is before the argument date;
false otherwise.
after
public boolean after(Date when)
true if this date is after the argument date;
false otherwise.
equals
public boolean equals(Object obj)
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.
true if the objects are the same;
false otherwise.
hashCode
public int hashCode()
toString
public String toString()
"Sat Aug 12 02:30:00 PDT 1995".
toLocaleString
public String toLocaleString()
%c" format supported by the strftime()
function of ISO C.
toGMTString
public String toGMTString()
"12 Aug 1995 02:30:00 GMT"
in which the day of the month is always one or two digits. The other fields have exactly the width shown. The time zone is always given as "GMT".
getTimezoneOffset
public int getTimezoneOffset()
All Packages Class Hierarchy This Package Previous Next Index