Log::Log4perl::DateFormat - Log4perl advanced date formatter helper class
use Log::Log4perl::DateFormat; my $format = Log::Log4perl::DateFormat->new("HH:mm:ss,SSS"); # Simple time, resolution in seconds my $time = time(); print $format->format($time), "\n"; # => "17:02:39,000" # Advanced time, resultion in milliseconds use Time::HiRes; my ($secs, $msecs) = Time::HiRes::gettimeofday(); print $format->format($secs, $msecs), "\n"; # => "17:02:39,959"
Log::Log4perl::DateFormat is a low-level helper class for the advanced date formatting functions in Log::Log4perl::Layout::PatternLayout.
Log::Log4perl::DateFormat
Log::Log4perl::Layout::PatternLayout
Unless you're writing your own Layout class like Log::Log4perl::Layout::PatternLayout, there's probably not much use for you to read this.
Log::Log4perl::DateFormat is a formatter which allows dates to be formatted according to the log4j spec on
http://jakarta.apache.org/log4j/docs/api/org/apache/log4j/PatternLayout.html
which allows the following placeholders to be recognized and processed:
Symbol Meaning Presentation Example ------ ------- ------------ ------- G era designator (Text) AD y year (Number) 1996 M month in year (Text & Number) July & 07 d day in month (Number) 10 h hour in am/pm (1~12) (Number) 12 H hour in day (0~23) (Number) 0 m minute in hour (Number) 30 s second in minute (Number) 55 S millisecond (Number) 978 E day in week (Text) Tuesday D day in year (Number) 189 F day of week in month (Number) 2 (2nd Wed in July) w week in year (Number) 27 W week in month (Number) 2 a am/pm marker (Text) PM k hour in day (1~24) (Number) 24 K hour in am/pm (0~11) (Number) 0 z time zone (Text) Pacific Standard Time ' escape for text (Delimiter) '' single quote (Literal) '
For example, if you want to format the current Unix time in "MM/dd HH:mm" format, all you have to do is this:
"MM/dd HH:mm"
use Log::Log4perl::DateFormat; my $format = Log::Log4perl::DateFormat->new("MM/dd HH:mm"); my $time = time(); print $format->format($time), "\n";
While the new() method is expensive, because it parses the format strings and sets up all kinds of structures behind the scenes, followup calls to format() are fast, because DateFormat will just call localtime() and sprintf() once to return the formatted date/time string.
new()
format()
DateFormat
localtime()
sprintf()
So, typically, you would initialize the formatter once and then reuse it over and over again to display all kinds of time values.
Also, for your convenience, the following predefined formats are available, just as outlined in the log4j spec:
Format Equivalent Example ABSOLUTE "HH:mm:ss,SSS" "15:49:37,459" DATE "dd MMM yyyy HH:mm:ss,SSS" "06 Nov 1994 15:49:37,459" ISO8601 "yyyy-MM-dd HH:mm:ss,SSS" "1999-11-27 15:49:37,459"
So, instead of passing
Log::Log4perl::DateFormat->new("HH:mm:ss,SSS");
you could just as well say
Log::Log4perl::DateFormat->new("ABSOLUTE");
and get the same result later on.
The following placeholders are currently not recognized, unless someone (and that could be you :) implements them:
F day of week in month w week in year W week in month k hour in day K hour in am/pm z timezone
Also, Log::Log4perl::DateFormat just knows about English week and month names, internationalization support has to be added.
Mike Schilli, <log4perl@perlmeister.com>
To install Log::Log4perl, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Log::Log4perl
CPAN shell
perl -MCPAN -e shell install Log::Log4perl
For more information on module installation, please visit the detailed CPAN module installation guide.