Provided by: liblog-log4perl-perl_1.57-1_all bug

NAME

       Log::Log4perl::Filter::Boolean - Special filter to combine the results of others

SYNOPSIS

           log4perl.logger = WARN, AppWarn, AppError

           log4perl.filter.Match1       = sub { /let this through/ }
           log4perl.filter.Match2       = sub { /and that, too/ }
           log4perl.filter.MyBoolean       = Log::Log4perl::Filter::Boolean
           log4perl.filter.MyBoolean.logic = Match1 || Match2

           log4perl.appender.Screen        = Log::Dispatch::Screen
           log4perl.appender.Screen.Filter = MyBoolean
           log4perl.appender.Screen.layout = Log::Log4perl::Layout::SimpleLayout

DESCRIPTION

       Sometimes, it's useful to combine the output of various filters to arrive at a log/no log
       decision. While Log4j, Log4perl's mother ship, chose to implement this feature as a filter
       chain, similar to Linux' IP chains, Log4perl tries a different approach.

       Typically, filter results will not need to be passed along in chains but combined in a
       programmatic manner using boolean logic. "Log if this filter says 'yes' and that filter
       says 'no'" is a fairly common requirement but hard to implement as a chain.

       "Log::Log4perl::Filter::Boolean" is a special predefined custom filter for Log4perl which
       combines the results of other custom filters in arbitrary ways, using boolean expressions:

           log4perl.logger = WARN, AppWarn, AppError

           log4perl.filter.Match1       = sub { /let this through/ }
           log4perl.filter.Match2       = sub { /and that, too/ }
           log4perl.filter.MyBoolean       = Log::Log4perl::Filter::Boolean
           log4perl.filter.MyBoolean.logic = Match1 || Match2

           log4perl.appender.Screen        = Log::Dispatch::Screen
           log4perl.appender.Screen.Filter = MyBoolean
           log4perl.appender.Screen.layout = Log::Log4perl::Layout::SimpleLayout

       "Log::Log4perl::Filter::Boolean"'s boolean expressions allow for combining different
       appenders by name using AND (&& or &), OR (|| or |) and NOT (!) as logical expressions.
       Parentheses are used for grouping. Precedence follows standard Perl. Here's a bunch of
       examples:

           Match1 && !Match2            # Match1 and not Match2
           !(Match1 || Match2)          # Neither Match1 nor Match2
           (Match1 && Match2) || Match3 # Both Match1 and Match2 or Match3

SEE ALSO

       Log::Log4perl::Filter, Log::Log4perl::Filter::LevelMatch,
       Log::Log4perl::Filter::LevelRange, Log::Log4perl::Filter::MDC,
       Log::Log4perl::Filter::StringRange

LICENSE

       Copyright 2002-2013 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

AUTHOR

       Please contribute patches to the project on Github:

           http://github.com/mschilli/log4perl

       Send bug reports or requests for enhancements to the authors via our

       MAILING LIST (questions, bug reports, suggestions/patches):
       log4perl-devel@lists.sourceforge.net

       Authors (please contact them via the list above, not directly): Mike Schilli
       <m@perlmeister.com>, Kevin Goess <cpan@goess.org>

       Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy
       Bopp, Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James
       FitzGibbon, Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander
       Hartmaier  David Hull, Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett
       Rann, Peter Rabbitson, Erik Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac
       Yang.