133 lines
2.9 KiB
Plaintext
133 lines
2.9 KiB
Plaintext
# PODNAME: Moose::Cookbook::Legacy::Table_ClassMetaclass
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# ABSTRACT: Adding a "table" attribute to the metaclass
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__END__
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=pod
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=encoding UTF-8
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=head1 NAME
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Moose::Cookbook::Legacy::Table_ClassMetaclass - Adding a "table" attribute to the metaclass
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=head1 VERSION
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version 2.2207
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=head1 SYNOPSIS
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package MyApp::Meta::Class;
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use Moose;
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extends 'Moose::Meta::Class';
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has table => (
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is => 'rw',
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isa => 'Str',
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);
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=head1 DESCRIPTION
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B<WARNING: Subclassing metaclasses (as opposed to providing metaclass traits)
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is strongly discouraged. This recipe is provided solely for reference when
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encountering older code that does this.>
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In this recipe, we'll create a new metaclass which has a "table"
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attribute. This metaclass is for classes associated with a DBMS table,
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as one might do for an ORM.
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In this example, the table name is just a string, but in a real ORM
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the table might be an object describing the table.
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=head1 THE METACLASS
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This really is as simple as the recipe L</SYNOPSIS> shows. The trick
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is getting your classes to use this metaclass, and providing some sort
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of sugar for declaring the table. This is covered in
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L<Moose::Cookbook::Extending::Recipe2>, which shows how to make a
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module like C<Moose.pm> itself, with sugar like C<has_table()>.
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=head2 Using this Metaclass in Practice
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Accessing this new C<table> attribute is quite simple. Given a class
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named C<MyApp::User>, we could simply write the following:
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my $table = MyApp::User->meta->table;
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As long as C<MyApp::User> has arranged to use C<MyApp::Meta::Class> as
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its metaclass, this method call just works. If we want to be more
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careful, we can check the metaclass's class:
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$table = MyApp::User->meta->table
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if MyApp::User->meta->isa('MyApp::Meta::Class');
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=head1 CONCLUSION
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Creating custom metaclass is trivial. Using it is a little harder, and
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is covered in other recipes. We will also talk about applying traits
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to a class metaclass, which is a more flexible and cooperative
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implementation.
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=head1 SEE ALSO
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L<Moose::Cookbook::Meta::Recipe5> - The "table" attribute implemented
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as a metaclass trait
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L<Moose::Cookbook::Extending::Recipe2> - Acting like Moose.pm and
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providing sugar Moose-style
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=head1 AUTHORS
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=over 4
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=item *
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Stevan Little <stevan@cpan.org>
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=item *
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Dave Rolsky <autarch@urth.org>
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=item *
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Jesse Luehrs <doy@cpan.org>
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=item *
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Shawn M Moore <sartak@cpan.org>
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=item *
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יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>
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=item *
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Karen Etheridge <ether@cpan.org>
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=item *
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Florian Ragwitz <rafl@debian.org>
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=item *
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Hans Dieter Pearcey <hdp@cpan.org>
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=item *
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Chris Prather <chris@prather.org>
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=item *
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Matt S Trout <mstrout@cpan.org>
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=back
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=head1 COPYRIGHT AND LICENSE
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This software is copyright (c) 2006 by Infinity Interactive, Inc.
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This is free software; you can redistribute it and/or modify it under
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the same terms as the Perl 5 programming language system itself.
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=cut
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