Moose::Cookbook::Meta::Table_MeUseraContributed)PMoose::Cookbook::Meta::Table_MetaclassTrait(3pm)



NAME
       Moose::Cookbook::Meta::Table_MetaclassTrait - Adding a "table" attribute as a metaclass
       trait

VERSION
       version 2.1213

SYNOPSIS
         # in lib/MyApp/Meta/Class/Trait/HasTable.pm
         package MyApp::Meta::Class::Trait::HasTable;
         use Moose::Role;
         Moose::Util::meta_class_alias('HasTable');

         has table => (
             is  => 'rw',
             isa => 'Str',
         );

         # in lib/MyApp/User.pm
         package MyApp::User;
         use Moose -traits => 'HasTable';

         __PACKAGE__->meta->table('User');

DESCRIPTION
       In this recipe, we'll create a class metaclass trait which has a "table" attribute. This
       trait is for classes associated with a DBMS table, as one might do for an ORM.

       In this example, the table name is just a string, but in a real ORM the table might be an
       object describing the table.

THE METACLASS TRAIT
       This really is as simple as the recipe "SYNOPSIS" shows. The trick is getting your classes
       to use this metaclass, and providing some sort of sugar for declaring the table. This is
       covered in Moose::Cookbook::Extending::Debugging_BaseClassRole, which shows how to make a
       module like "Moose.pm" itself, with sugar like "has_table()".

   Using this Metaclass Trait in Practice
       Accessing this new "table" attribute is quite simple. Given a class named "MyApp::User",
       we could simply write the following:

         my $table = MyApp::User->meta->table;

       As long as "MyApp::User" has arranged to apply the "MyApp::Meta::Class::Trait::HasTable"
       to its metaclass, this method call just works. If we want to be more careful, we can check
       that the class metaclass object has a "table" method:

         $table = MyApp::User->meta->table
             if MyApp::User->meta->can('table');

       In theory, this is not entirely correct, since the metaclass might be getting its "table"
       method from a different trait. In practice, you are unlikely to encounter this sort of
       problem.

RECIPE CAVEAT
       This recipe doesn't work when you paste it all into a single file. This is because the
       "use Moose -traits => 'HasTable';" line ends up being executed before the "table"
       attribute is defined.

       When the two packages are separate files, this just works.

SEE ALSO
       Moose::Cookbook::Meta::Labeled_AttributeTrait - Labels implemented via attribute traits

AUTHORS
       ·   Stevan Little <stevan.little AT iinteractive.com>

       ·   Dave Rolsky <autarch AT urth.org>

       ·   Jesse Luehrs <doy AT tozt.net>

       ·   Shawn M Moore <code AT sartak.org>

       ·   XXXX XXX'XX (Yuval Kogman) <nothingmuch AT woobling.org>

       ·   Karen Etheridge <ether AT cpan.org>

       ·   Florian Ragwitz <rafl AT debian.org>

       ·   Hans Dieter Pearcey <hdp AT weftsoar.net>

       ·   Chris Prather <chris AT prather.org>

       ·   Matt S Trout <mst AT shadowcat.uk>

COPYRIGHT AND LICENSE
       This software is copyright (c) 2006 by Infinity Interactive, Inc..

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.



perl v5.20.1                                2014-Moose::Cookbook::Meta::Table_MetaclassTrait(3pm)