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From "Steve Cohen" <SCo...@sportvision.com>
Subject RE: [NET] Here's an Ant bug that we should look into fixing
Date Sun, 09 Mar 2003 20:32:16 GMT
Another RFC document of interest is http://www.rfc-editor.org/rfc/rfc2640.txt.
I at first thought that this document might be heading down the paths I was looking at, but
alas, it is approaching i18n only from the point of view of character sets used, it has nothing
to do with date formats.  In any case, its recommendations have not been widely adopted.


-----Original Message-----
From:	Steve Cohen
Sent:	Sun 3/9/2003 2:18 PM
To:	Jakarta Commons Developers List; Jakarta Commons Developers List
Cc:	
Subject:	RE: [NET] Here's an Ant bug that we should look into fixing

I had thought I might hear some replies to this.  The silence has been deafening.  

I have been thinking about the issue, though, in particular where commons-net.ftp might have
to go in order to really implement the ambitious spec laid out for it by clients such as ant,
which have chosen to use it.

Of particular note here is the "depends" (or synonym "newer") attribute of the ant <ftp>
task.  This runs aground on the issue of parsing the date.  In the first place, there are
the issues of general listing format (unix, NT, VMS, etc.).  In the second place, though,
within these categories are issues of date format.  This devolves into a thicket of locale-type
issues:

Does month come before date?  
In which language are the names of the months coded?

To solve this, the scope of parser definition needs to be significantly expanded.

Things might be better if there was any mechanism within the FTP specification for the server
to expose its format to a client.  No such mechanism exists, however.  In fact RFC959, the
FTP spec is intentionally vague on this point: 

"Since the information on a file may vary widely from system
to system, this information may be hard to use automatically
in a program, but may be quite useful to a human user."

http://www.ietf.org/rfc/rfc959.txt

In other words, FTP was never meant to be used in such an automated fashion.

Nonetheless, with the specification of parameters easily passed in by something like an ant
task, it might be possible to define a parser sufficiently to perform this task.  These parameters
include:

1) os type of FTP server(unix, NT, OS2, VMS, etc.)
2) date format - to define ordering of date components - 
"MMM dd" or "dd MMM", etc. as in simple date format
3) locale - to define actual abbreviations of the months.

>>From 2 and 3 it is possible to build a Locale-specific SimpleDateFormat
capable of parsing dates on a particular system.  This object contains the names and abbreviations
of the month.

This immediately raises the question of how to divvy up the parsing duties between the regular
expression and the SimpleDateFormat.   It seems as if the format string must be used to construct
the part of the regex in the correct order.  Then the SimpleDateFormat would be used to actually
parse the date.  All "optimizations" such as assuming a constant character width of 3 for
month abbreviations are out the window here - they work for many languages, but not for all.
 French, for example, uses periods and varying lengths.

A cautionary note: one would have to inspect actual ftp sites to determine whether they actually
the abbreviations specified in java Locales.

Comments?  Is this a Pandora's box that we don't want to open?






-----Original Message-----
From:	Steve Cohen
Sent:	Wed 3/5/2003 1:53 PM
To:	Jakarta Commons Developers List
Cc:	
Subject:	[NET] Here's an Ant bug that we should look into fixing

The <ftp> task of ant doesn't work right because we don't parse
non-english date formats.

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=14333
-----------------------------------------------
Steve Cohen
Sr. Software Engineer
Sportvision Inc.
scohen@sportvision.com
http://www.sportvision.com

Please note: As a result of the merger of 
Ignite Sports and Sportvision, my email address 
has changed to scohen@sportvision.com





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