/ 
MooseX-Object-Pluggable-0.0007
River stage two • 12 direct dependents • 60 total dependents
/ MooseX::Object::Pluggable

NAME

MooseX::Object::Pluggable - Make your classes pluggable

SYNOPSIS

package MyApp;
use Moose;

with 'MooseX::Object::Pluggable';

...

package MyApp::Plugin::Pretty;
use Moose::Role;

sub pretty{ print "I am pretty" }

1;

#
use MyApp;
my $app = MyApp->new;
$app->load_plugin('Pretty');
$app->pretty;

DESCRIPTION

This module is meant to be loaded as a role from Moose-based classes it will add five methods and four attributes to assist you with the loading and handling of plugins and extensions for plugins. I understand that this may pollute your namespace, however I took great care in using the least ambiguous names possible.

How plugins Work

Plugins and extensions are just Roles by a fancy name. They are loaded at runtime on demand and are instance, not class based. This means that if you have more than one instance of a class they can all have different plugins loaded. This is a feature.

Plugin methods are allowed to around, before, after their consuming classes, so it is important to watch for load order as plugins can and will overload each other. You may also add attributes through has.

Please note that when you load at runtime you lose the ability to wrap BUILD and roles using has will not go through comile time checks like required and <default>.

Even though override will work , I STRONGLY discourage it's use and a warning will be thrown if you try to use it. This is closely linked to the way multiple roles being applies is handles and is not likely to change. override bevavior is closely linked to inheritance and thus will likely not work as you expect it in multiple inheritance situations. Point being, save yourself the headache.

How plugins are loaded

When roles are applied at runtime an anonymous class will wrap your class and $self->blessed and ref $self will no longer return the name of your object, they will instead return the name of the anonymous class created at runtime. See _original_class_name.

Notice regarding extensions.

Because I have been able to identify a real-world use case for the extension mechanism I have decided to deprecate it and remove it in the next major release.

Usage

For a simple example see the tests included in this distribution.

Attributes

_plugin_ns

String. The prefix to use for plugin names provided. MyApp::Plugin is sensible.

_plugin_ext

Boolean. Indicates whether we should attempt to load plugin extensions. Defaults to true;

_plugin_ext_ns

THIS FUNCTIONALITY HAS BEEN DEPRECATED AND WILL GO AWAY. If you use this, please email me, but I am fairly sure that nobody uses this at all and it's just adding bloat and making things kind of ugly.

String. The namespace plugin extensions have. Defaults to 'ExtensionFor'.

This means that is _plugin_ns is "MyApp::Plugin" and _plugin_ext_ns is "ExtensionFor" loading plugin "Bar" would search for extensions in "MyApp::Plugin::Bar::ExtensionFor::*".

_plugin_app_ns

ArrayRef, Accessor automatically dereferences into array on a read call. By default will be filled with the class name and it's prescedents, it is used to determine which directories to look for plugins as well as which plugins take presedence upon namespace collitions. This allows you to subclass a pluggable class and still use it's plugins while using yours first if they are available.

_plugin_locator

An automatically built instance of Module::Pluggable::Object used to locate available plugins.

Public Methods

load_plugin $plugin

Load the apropriate role for $plugin as well as any extensions it provides if extensions are enabled.

load_plugins @plugins

Load all @plugins.

load_plugin_ext

THIS FUNCTIONALITY HAS BEEN DEPRECATED AND WILL GO AWAY. If you use this, please email me, but I am fairly sure that nobody uses this at all and it's just adding bloat and making things kind of ugly.

Will load any extensions for a particular plugin. This should be called automatically by load_plugin so you don't need to worry about it. It basically attempts to load any extension that exists for a plugin that is already loaded. The only reason for using this is if you want to keep _plugin_ext as false and only load extensions manually, which I don't recommend.

_original_class_name

Because of the way roles apply $self->blessed and ref $self will no longer return what you expect. Instead use this class to get your original class name.

Private Methods

There's nothing stopping you from using these, but if you are using them for anything thats not really complicated you are probably doing something wrong. Some of these may be inlined in the future if performance becomes an issue (which I doubt).

_role_from_plugin $plugin

Creates a role name from a plugin name. If the plugin name is prepended with a + it will be treated as a full name returned as is. Otherwise a string consisting of $plugin prepended with the _plugin_ns and the first valid value from _plugin_app_ns will be returned. Example

#assuming appname MyApp and C<_plugin_ns> 'Plugin'
$self->_role_from_plugin("MyPlugin"); # MyApp::Plugin::MyPlugin

_load_and_apply_role $role

Require $role if it is not already loaded and apply it. This is the meat of this module.

_build_plugin_app_ns

Automatically builds the _plugin_app_ns attribute with the classes in the class presedence list that are not part of Moose.

_build_plugin_locator

Automatically creates a Module::Pluggable::Object instance with the correct search_path.

meta

Keep tests happy. See Moose

SEE ALSO

Moose, Moose::Role, Class::Inspector

AUTHOR

Guillermo Roditi, <groditi@cpan.org>

BUGS

Holler?

Please report any bugs or feature requests to bug-moosex-object-pluggable at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=MooseX-Object-Pluggable. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc MooseX-Object-Pluggable

You can also look for information at:

ACKNOWLEDGEMENTS

#Moose - Huge number of questions
Matt S Trout <mst@shadowcatsystems.co.uk> - ideas / planning.
Stevan Little - EVERYTHING. Without him this would have never happened.

COPYRIGHT

Copyright 2007 Guillermo Roditi. All Rights Reserved. This is free software; you may redistribute it and/or modify it under the same terms as Perl itself.