Log::Log4perl::Filter::Boolean(3pm) - phpMan

Filter::Boolean(3pm)           User Contributed Perl Documentation           Filter::Boolean(3pm)



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::StringRange

AUTHOR
       Mike Schilli, <log4perl AT perlmeister.com>, 2003



perl v5.10.0                                2003-08-11                       Filter::Boolean(3pm)

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