NAME

Log::Log4perl::Config::BaseConfigurator - Configurator Base Class

SYNOPSIS

This is a virtual base class, all configurators should be derived from it.

DESCRIPTION

METHODS

new

Constructor, typically called like

    my $config_parser = SomeConfigParser->new(
        file => $file,
    );

    my $data = $config_parser->parse();

Instead of file, the derived class SomeConfigParser may define any type of configuration input medium (e.g. url => 'http://foobar'). It just has to make sure its parse() method will later pull the input data from the medium specified.

The base class accepts a filename or a reference to an array of text lines:

file

Specifies a file which the parse() method later parses.

text

Specifies a reference to an array of scalars, representing configuration records (typically lines of a file). Also accepts a simple scalar, which it splits at its newlines and transforms it into an array:

    my $config_parser = MyYAMLParser->new(
        text => ['foo: bar',
                 'baz: bam',
                ],
    );

    my $data = $config_parser->parse();

If either file or text parameters have been specified in the constructor call, a later call to the configurator's text() method will return a reference to an array of configuration text lines. This will typically be used by the parse() method to process the input.

parse

Virtual method, needs to be defined by the derived class.

Parser requirements

If the parser provides variable substitution functionality, it has to implement it.
The parser's parse() method returns a reference to a hash of hashes (HoH). The top-most hash contains the top-level keywords (category, appender) as keys, associated with values which are references to more deeply nested hashes.
The log4perl. prefix (e.g. as used in the PropertyConfigurator class) is stripped, it's not part in the HoH structure.

Each Log4perl config value is indicated by the value key, as in

    $data->{category}->{Bar}->{Twix}->{value} = "WARN, Logfile"

EXAMPLES

The following Log::Log4perl configuration:

    log4perl.category.Bar.Twix        = WARN, Screen
    log4perl.appender.Screen          = Log::Log4perl::Appender::File
    log4perl.appender.Screen.filename = test.log
    log4perl.appender.Screen.layout   = Log::Log4perl::Layout::SimpleLayout

needs to be transformed by the parser's parse() method into this data structure:

    { appender => {
        Screen  => {
          layout => { 
            value  => "Log::Log4perl::Layout::SimpleLayout" },
            value  => "Log::Log4perl::Appender::Screen",
        },
      },
      category => { 
        Bar => { 
          Twix => { 
            value => "WARN, Screen" } 
        } }
    }

For a full-fledged example, check out the sample YAML parser implementation in eg/yamlparser. It uses a simple YAML syntax to specify the Log4perl configuration to illustrate the concept.

AUTHOR

Mike Schilli, <m@perlmeister.com>, 2004 Kevin Goess, <cpan@goess.org> Jan-2003

CPAN RT