tribble.util
Class Date

java.lang.Object
  java.util.Date
      tribble.util.Date

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Comparable<java.util.Date>

public class Date
extends java.util.Date

Immutable date/time value.

This class is identical to the standard java.util.Date class, except that its contents cannot be changed. Specifically, the setTime() method does not modify the object's value, but instead throws an exception. For all other purposes, objects of this type can be used anywhere java.util.Date objects are used.

Methods can return objects of this type as immutable values, i.e., the date objects cannot be modified after they are returned.

In addition, the special constants UNKNOWN and NEVER are provided which represent, respectively, an unknown date and a date that will never occur.

Since:

2003-02-10

Version:

$Revision: 1.1 $ $Date: 2003/02/26 01:22:01 $

Author:

David R. Tribble (david@tribble.com).
Copyright ©2003 by David R. Tribble, all rights reserved.
Permission is granted to freely use and distribute this source code provided that the original copyright and authorship notices remain intact.

See Also:

Serialized Form

Field Summary

static Date	NEVER Special date value: Never.
static long	TIME_NEVER Special time value: Never.
static long	TIME_UNKNOWN Special time value: Unknown.
static Date	UNKNOWN Special date value: Unknown.

Constructor Summary

Date()
Default constructor.

Date(java.util.Date date)
Constructor.

Date(long time)
Constructor.

Method Summary

boolean	after(java.util.Date when) Determine if this date occurs after a specified date.
boolean	before(java.util.Date when) Determine if this date occurs before a specified date.
void	setTime(long time) This method is not implemented.
java.lang.String	toString() Convert this date into its equivalent string representation.

Methods inherited from class java.util.Date

clone, compareTo, equals, getDate, getDay, getHours, getMinutes, getMonth, getSeconds, getTime, getTimezoneOffset, getYear, hashCode, parse, setDate, setHours, setMinutes, setMonth, setSeconds, setYear, toGMTString, toLocaleString, UTC

Methods inherited from class java.lang.Object

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

Field Detail

TIME_UNKNOWN

public static final long TIME_UNKNOWN

Special time value: Unknown.

See Also:

Constant Field Values

TIME_NEVER

public static final long TIME_NEVER

Special time value: Never.

See Also:

Constant Field Values

UNKNOWN

public static final Date UNKNOWN

Special date value: Unknown.

NEVER

public static final Date NEVER

Special date value: Never.

Constructor Detail

Date

public Date()

Default constructor. Sets this date to the current system time.

Since:

1.1, 2003-02-10

Date

public Date(long time)

Constructor.

Parameters:

time - A time value, measured in milliseconds since 1970-01-01 00:00:00.000 UTC.

Since:

1.1, 2003-02-10

Date

public Date(java.util.Date date)

Constructor.

Parameters:

date - A date value.

Since:

1.1, 2003-02-26

Method Detail

toString

public java.lang.String toString()

Convert this date into its equivalent string representation.

If this date is equal to UNKNOWN, the string returned is "unknown".

If this date is equal to NEVER, the string returned is "never".

Otherwise the string returned is 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 savings time). If time zone information is not available, then zzz is empty, consisting of no characters at all.
• yyyy is the year, as four decimal digits.

Overrides:

toString in class java.util.Date

Returns:

A string representation of this date.

Since:

1.1, 2003-02-26

after

public boolean after(java.util.Date when)

Determine if this date occurs after a specified date.

Dates equal to UNKNOWN occur before any other valid date, and dates equal to NEVER occur after any other valid date.

Overrides:

after in class java.util.Date

Parameters:

when - Another date to compare to this one.

Returns:

True if this date is strictly later in time than when, otherwise false.

Since:

1.1, 2003-02-26

before

public boolean before(java.util.Date when)

Determine if this date occurs before a specified date.

Dates equal to UNKNOWN occur before any other valid date, and dates equal to NEVER occur after any other valid date.

Overrides:

before in class java.util.Date

Parameters:

when - Another date to compare to this one.

Returns:

True if this date is strictly earlier in time than when, otherwise false.

Since:

1.1, 2003-02-26

setTime

public void setTime(long time)

This method is not implemented.

Overrides:

setTime in class java.util.Date

Throws:

java.lang.UnsupportedOperationException - (unchecked) Thrown always, indicating that this method is not implemented.

Since:

1.1, 2003-02-10