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Moose::Cookbook::Roles::ApplicationToInstance(3)	User Contributed Perl Documentation	  Moose::Cookbook::Roles::ApplicationToInstance(3)

NAME
Moose::Cookbook::Roles::ApplicationToInstance - Applying a role to an object instance VERSION
version 2.0604 SYNOPSIS
package MyApp::Role::Job::Manager; use List::Util qw( first ); use Moose::Role; has 'employees' => ( is => 'rw', isa => 'ArrayRef[Employee]', ); sub assign_work { my $self = shift; my $work = shift; my $employee = first { !$_->has_work } @{ $self->employees }; die 'All my employees have work to do!' unless $employee; $employee->work($work); } package main; my $lisa = Employee->new( name => 'Lisa' ); MyApp::Role::Job::Manager->meta->apply($lisa); my $homer = Employee->new( name => 'Homer' ); my $bart = Employee->new( name => 'Bart' ); my $marge = Employee->new( name => 'Marge' ); $lisa->employees( [ $homer, $bart, $marge ] ); $lisa->assign_work('mow the lawn'); DESCRIPTION
In this recipe, we show how a role can be applied to an object. In this specific case, we are giving an employee managerial responsibilities. Applying a role to an object is simple. The Moose::Meta::Role object provides an "apply" method. This method will do the right thing when given an object instance. MyApp::Role::Job::Manager->meta->apply($lisa); We could also use the "apply_all_roles" function from Moose::Util. apply_all_roles( $person, MyApp::Role::Job::Manager->meta ); The main advantage of using "apply_all_roles" is that it can be used to apply more than one role at a time. We could also pass parameters to the role we're applying: MyApp::Role::Job::Manager->meta->apply( $lisa, -alias => { assign_work => 'get_off_your_lazy_behind' }, ); We saw examples of how method exclusion and alias working in Moose::Cookbook::Roles::Restartable_AdvancedComposition. CONCLUSION
Applying a role to an object instance is a useful tool for adding behavior to existing objects. In our example, it is effective used to model a promotion. It can also be useful as a sort of controlled monkey-patching for existing code, particularly non-Moose code. For example, you could create a debugging role and apply it to an object at runtime. AUTHOR
Moose is maintained by the Moose Cabal, along with the help of many contributors. See "CABAL" in Moose and "CONTRIBUTORS" in Moose for details. COPYRIGHT AND LICENSE
This software is copyright (c) 2012 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 v5.16.2 2012-09-19 Moose::Cookbook::Roles::ApplicationToInstance(3)

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Moose::Util::MetaRole(3)				User Contributed Perl Documentation				  Moose::Util::MetaRole(3)

NAME
Moose::Util::MetaRole - Apply roles to any metaclass, as well as the object base class VERSION
version 2.0604 SYNOPSIS
package MyApp::Moose; use Moose (); use Moose::Exporter; use Moose::Util::MetaRole; use MyApp::Role::Meta::Class; use MyApp::Role::Meta::Method::Constructor; use MyApp::Role::Object; Moose::Exporter->setup_import_methods( also => 'Moose' ); sub init_meta { shift; my %args = @_; Moose->init_meta(%args); Moose::Util::MetaRole::apply_metaroles( for => $args{for_class}, class_metaroles => { class => => ['MyApp::Role::Meta::Class'], constructor => ['MyApp::Role::Meta::Method::Constructor'], }, ); Moose::Util::MetaRole::apply_base_class_roles( for => $args{for_class}, roles => ['MyApp::Role::Object'], ); return $args{for_class}->meta(); } DESCRIPTION
This utility module is designed to help authors of Moose extensions write extensions that are able to cooperate with other Moose extensions. To do this, you must write your extensions as roles, which can then be dynamically applied to the caller's metaclasses. This module makes sure to preserve any existing superclasses and roles already set for the meta objects, which means that any number of extensions can apply roles in any order. USAGE
The easiest way to use this module is through Moose::Exporter, which can generate the appropriate "init_meta" method for you, and make sure it is called when imported. FUNCTIONS
This module provides two functions. apply_metaroles( ... ) This function will apply roles to one or more metaclasses for the specified class. It will return a new metaclass object for the class or role passed in the "for" parameter. It accepts the following parameters: o for => $name This specifies the class or for which to alter the meta classes. This can be a package name, or an appropriate meta-object (a Moose::Meta::Class or Moose::Meta::Role). o class_metaroles => \%roles This is a hash reference specifying which metaroles will be applied to the class metaclass and its contained metaclasses and helper classes. Each key should in turn point to an array reference of role names. It accepts the following keys: class attribute method wrapped_method instance constructor destructor error o role_metaroles => \%roles This is a hash reference specifying which metaroles will be applied to the role metaclass and its contained metaclasses and helper classes. It accepts the following keys: role attribute method required_method conflicting_method application_to_class application_to_role application_to_instance application_role_summation applied_attribute apply_base_class_roles( for => $class, roles => @roles ) This function will apply the specified roles to the object's base class. BUGS
See "BUGS" in Moose for details on reporting bugs. AUTHOR
Moose is maintained by the Moose Cabal, along with the help of many contributors. See "CABAL" in Moose and "CONTRIBUTORS" in Moose for details. COPYRIGHT AND LICENSE
This software is copyright (c) 2012 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 v5.16.2 2012-09-19 Moose::Util::MetaRole(3)
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