NAME
   Class::Default - Static calls apply to a default instantiation

SYNOPSIS
     # Create the defaulted class
     package Foo::Base;

     use base 'Class::Default';

     sub new { bless {}, $_[0] }

     sub show {
         my $self = shift->_self;
         "$self";
     }

     # Do something to the default object

     package main;

     print Foo::Bar->show;

     # Prints 'Foo::Bar=HASH(0x80d22f8)'

DESCRIPTION
   Class::Default provides a mechanism to allow your class to take static
   method calls and apply it to a default instantiation of an object. It
   provides a flexibility to an API that allows it to be used more
   confortably in different situations.

   A good example of this technique in use is CGI.pm. When you use a static
   method, like "CGI-"header>, your call is being applied to a default
   instantiation of a CGI object.

   This technique appears to be especially usefull when writing modules
   that you want to be used in either a single use or a persistant
   environment. In a CGI like environment, you want the simplicity of a
   static interface. You can call "Class-"method> directly, without having
   to pass an instantiation around constantly.

USING THE MODULES
   Class::Default provides a couple of levels of control. They start with
   simple enabling the method to apply to the default instantation, and
   move on to providing some level of control over the creation of the
   default object.

 Inheriting from Class::Default
   To start, you will need to inherit from Class::Default. You do this in
   the normal manner, using something like "use base 'Class::Default'", or
   setting the @ISA value directly. "Class::Default" does not have a
   default constructor or any public methods, so you should be able to use
   it a multiple inheritance situation without any implications.

 Making method work
   To make your class work with Class::Default you need to make a small
   adjustment to each method that you would like to be able to access the
   default object.

   A typical method will look something like the following

     sub foobar {
         my $self = shift;

         # Do whatever the method does
     }

   To make the method work with Class::Default, you should change it to the
   following

     sub foobar {
         my $self = shift->_self;

         # Do whatever the method does
     }

   This change is very low impact, easy to use, and will not make any other
   differences to the way your code works.

 Control over the default object
   When needed, Class::Default will make a new instantation of your class
   and cache it to be used whenever a static call is made. It does this in
   the simplest way possible, by calling "Class-"new()> with no arguments.

   This is fine if you have a very pure class that can handle creating a
   new object without any arguments, but many classes expect some sort of
   argument to the the constructor, and indeed that the constructor that
   should be used it the "new" method.

   Enter the "_create_default_object" method. By overloading the
   "_create_default_object" method in your class, you can custom create the
   default object. This will used to create the default object on demand,
   the first time a method is called. For example, the following class
   demonstrate the use of "_create_default_object" to set some values in
   the default object.

     package Slashdot::User;

     use base 'Class::Default';

     # Constructor
     sub new {
           my $class = shift;
           my $name = shift;

           my $self = {
                   name => $name,
                   favourite_color => '',
           };

           return bless $self, $class;
     }

     # Default constructor
     sub _create_default_object {
           my $class = shift;

           my $self = $class->new( 'Anonymous Coward' );
           $self->{favourite_color} = 'Orange';

           return $self;
     }

     sub name {
           $_[0]->_self->{name};
     }

     sub favourite_color {
           $_[0]->_self->{favourite_color};
     }

   That provides a statically accessible default object that could be used
   as in the following manner.

     print "The default slashdot user is " . Slashdot::User->name
         . " and they like the colour " . Slashdot::User->favourite_color;

   Remember that the default object is persistant, so changes made to the
   statically accessible object can be recovered later.

 Getting access to the default object
   There are a few ways to do this, but the easiest way is to simple do the
   following

     my $default = Slashdot::User->_get_default;

METHODS
 _self
   Used by methods to make the method apply to the default object if called
   statically without affecting normal object methods.

 _class
   The "_class" method provides the opposite of the "_self" method. Instead
   of always getting an object, "_class" will always get the class name, so
   a method can be guarenteed to run in a static context. This is not
   essential to the use of a "Class::Default" module, but is provided as a
   convenience.

 _get_default
   Used to get the default object directly.

 _create_default_object
   To be overloaded by your class to set any properties to the default
   object at creation time.

BUGS
   No known bugs, but suggestions are welcome

SUPPORT
   Bugs should be reported via the CPAN bug tracker at

   <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Default>

   For other issues, contact the author

AUTHOR
   Adam Kennedy <[email protected]>

SEE ALSO
   <http://ali.as/>, Class::Singleton

COPYRIGHT
   Copyright (c) 2002 - 2006 Adam Kennedy.

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

   The full text of the license can be found in the LICENSE file included
   with this module.

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