This package implements Date/Time manipulations, arithmetics and
formatting in an easy to use manner for Java and Waba (Java for
small devices like PDAs).
This package was created for various reasons, the most important ones:
- Practically every computer system and/or programming language has a
different type of Date and Time implementation,
- the range of Dates seems to be sometimes dependent on the implementor,
- to manipulate (set and get) Date and Time fields is usually cumbersome
and not standardized by any means (e.g. 'first Monday in September',
'last working day of the year', 'Easter Sunday, Good Friday according to the
Gregorian/Julian calendar', etc.),
- to do primitive arithmetics like subtracting one Date (and/orTime) from the other,
or adding/subtracting milliseconds or whole days to/from a Date (and/or Time),
- neither Java 1.3 nor Waba have Date and Time classes implemented, which
would be easy to use for the above mentioned purposes (SuperWaba 1.2x Date
even limits the range of Dates such that dates earlier than 1983-01-01 are
not possible!),
- Java/Waba need a sophisticated, but simple/easy to use and serializable Date/Time
package!
(Being also capable of dealing with Julian and Gregorian calendar
issues. Today, all the world uses the Gregorian calendar for civil purposes,
but switched to it at various dates in the past.)
The datergf package for Java and Waba follows the ideas of "datergf.cmd", a little
date manipulation/arithmetic function package written for the
scripting language Rexx, which is
available in the form of commercial and (opensourced) free interpreters for practically
every operating system in the world. Its syntax is simple, hence easy to learn
and nicely maintainable:
- In the meantime a fully Object oriented version (with Smalltalk's object model,
enhanced with multiple inheritance) has been created by IBM:
Object Rexx. It's free
for Linux and OS/2, available for AIX and Windows 97/NT/2000/ME/XP, allowing easy
access to OLE/ActiveX-automation as well as to the WSH ('Windows Scripting Host').
- IBM has handed over the source-code of Object REXX to the non-profit special interest group (SIG)
Rexx Language Association (RexxLA). Since April 2005 the
"Open Object Rexx (ooRexx)" has been made available
for multiple platforms (most notably the Linux and the Windows platforms) for free.
Acknowledgements:
Rony G. Flatscher, Vienna (Austria/Europe), 2001-04-07, 2005-12-28
{This package was developed while working temporarily (from April 2000 through April 2001)
at the University of Essen (Germany), starting
out from the Vienna University of Economics and Business
Administration (a.k.a. "WU" - Wirtschafts-Universität Wien)). This was taken
as an opportunity to learn about Java and Waba.
License:
------------------------ Apache Version 2.0 license -------------------------
Copyright (C) 2001-2005 Rony G. Flatscher
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
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