man Log::Dispatch::Output () - Base class for all Log::Dispatch::* object


Log::Dispatch::Output - Base class for all Log::Dispatch::* object


  package Log::Dispatch::MySubclass;

  use Log::Dispatch::Output;
  use base qw( Log::Dispatch::Output );

  sub new
      my $proto = shift;
      my $class = ref $proto || $proto;

      my %p = @_;

      my $self = bless {}, $class


      # Do more if you like

  sub log_message
      my $self = shift;
      my %p = @_;

      # Do something with message in $p{message}


This module is the base class from which all Log::Dispatch::* objects should be derived.


* new(%p)
This must be overridden in a subclass. Takes the following parameters:
* name ($)
The name of the object (not the filename!). Required.
* min_level ($)
The minimum logging level this object will accept. See the Log::Dispatch documentation for more information. Required.
* max_level ($)
The maximum logging level this obejct will accept. See the Log::Dispatch documentation for more information. This is not required. By default the maximum is the highest possible level (which means functionally that the object has no maximum).
* callbacks( \& or [ \&, \&, ... ] )
This parameter may be a single subroutine reference or an array reference of subroutine references. These callbacks will be called in the order they are given and passed a hash containing the following keys:
 ( message => $log_message, level => $log_level )
The callbacks are expected to modify the message and then return a single scalar containing that modified message. These callbacks will be called when either the CWlog or CWlog_to methods are called and will only be applied to a given message once. If they do not return the message then you will get no output. Make sure to return the message!
* _basic_init(%p)
This should be called from a subclass's constructor. Make sure to pass the arguments in CW@_ to it. It sets the object's name and minimum level. It also sets up two other attributes which are used by other Log::Dispatch::Output methods, level_names and level_numbers.
* name
Returns the object's name.
* min_level
Returns the object's minimum log level.
* max_level
Returns the object's maximum log level.
* accepted_levels
Returns a list of the object's accepted levels (by name) from minimum to maximum.
* log( level => $, message => $ )
Sends a message if the level is greater than or equal to the object's minimum level. This method applies any message formatting callbacks that the object may have.
* _should_log ($)
This method is called from the CWlog() method with the log level of the message to be logged as an argument. It returns a boolean value indicating whether or not the message should be logged by this particular object. The CWlog() method will not process the message if the return value is false.
* _level_as_number ($)
This method will take a log level as a string (or a number) and return the number of that log level. If not given an argument, it returns the calling object's log level instead. If it cannot determine the level then it will issue a warning and return undef.


This class should be used as the base class for all logging objects you create that you would like to work under the Log::Dispatch architecture. Subclassing is fairly trivial. For most subclasses, if you simply copy the code in the SYNOPSIS and then put some functionality into the CWlog_message method then you should be all set. Please make sure to use the CW_basic_init method as directed.


Dave Rolsky, <>