# Moose::Cookbook::Roles::ApplicationToInstance - phpMan

## NAME
    [Moose::Cookbook::Roles::ApplicationToInstance] - Applying a role to an
    object instance

## VERSION
    version 2.2200

## 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.

## AUTHORS
    *   Stevan Little <<stevan@cpan.org>>

    *   Dave Rolsky <<autarch@urth.org>>

    *   Jesse Luehrs <<doy@cpan.org>>

    *   Shawn M Moore <<sartak@cpan.org>>

    *   יובל קוג'מן (Yuval Kogman) <<nothingmuch@woobling.org>>

    *   Karen Etheridge <<ether@cpan.org>>

    *   Florian Ragwitz <<rafl@debian.org>>

    *   Hans Dieter Pearcey <<hdp@cpan.org>>

    *   Chris Prather <<chris@prather.org>>

    *   Matt S Trout <<mstrout@cpan.org>>

## 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.