man Jifty::ClassLoader (3): Loads the application classes

DESCRIPTION

"Jifty::ClassLoader" loads all of the application's model and action classes, generating classes on the fly for Collections of pre-existing models.

new

Returns a new ClassLoader object. Doing this installs a hook into @INC that allows Jifty::ClassLoader to dynamically create needed classes if they do not exist already. This works because if use/require encounters a blessed reference in @INC, it will invoke the INC method with the name of the module it is searching for on the reference.

Takes one mandatory argument, "base", which should be the the application's or a plugin's base path; all of the classes under this will be automatically loaded.

Jifty::ClassLoader objects are singletons per "base". If you call "new" and a class loader for the given base has already been initialized, this will return a reference to that object rather than creating a new one.

INC

The hook that is called when a module has been "require"'d that cannot be found on disk. The following stub classes are auto-generated the class loader.

Here the "Application" indicates the name of the application the class loader is being applied to. However, this really just refers to the "base" argument passed to the constructor, so it could refer to a plugin class or just about anything else.

Application: An empty application base class is created that doesn't provide any methods or inherit from anything.
Application::Action: An empty mixin class for all actions in your application. Should not inherit from Jifty::Action.
Application::Action::[Verb][Something]: If Application::Model::Something is a valid model class and Verb is one of ``Create'', ``Search'', ``Update'', ``Execute'', or ``Delete'', then it creates a subclass of Application::Action::Record::Verb Models can control which actions are generated by overriding ``autogenerate_action'' in Jifty::Record. See also ``is_private'' in Jifty::Record and ``is_protected'' in Jifty::Record.
Application::Action::Something: The class loader will search for a plugin Plugin such that "Plugin::Action::Something" exists. It will then create an empty class named Application::Action::Something that descends from Plugin::Action::Something.
This means that a plugin may be written to allow the application to override the default implementation used by the plugin as long as the plugin uses the application version of the class.
Application::Action::Record::Something: An empty class that descends from the matching Jifty class, Jifty::Action::Record::Something. This is generally used to build application-specific descendants of Jifty::Action::Record::Create, Jifty::Action::Record::Execute, Jifty::Action::Record::Search, Jifty::Action::Record::Update, or Jifty::Action::Record::Delete.
Application::Bootstrap: An empty class that descends from Jifty::Bootstrap.
Application::Collection: An empty class that descends from Jifty::Collection is created.
Application::CurrentUser: An empty class that descends from Jifty::CurrentUser.
Application::Dispatcher: An empty class that descends from Jifty::Dispatcher.
Application::Event: An empty class that descends from Jifty::Event is created.
Application::Event::Model: An empty class that descents from Jifty::Event::Model is created.
Application::Event::Model::Something: If Application::Model::Something is a valid model class, then it creates an empty descendant of Application::Event::Model with the "record_class" set to Application::Model::Something.
Application::Handle: An empty class that descends from Jifty::Handle is created.
Application::Model::Something: If "Plugin::Model::Something" exists and is a model class, then it creates a subclass of it named "Application::Model::Something" for the local application.
This allows an application to customize a model provided by a subclass (or choose not to). Plugins should be written to use the application's version.
Application::Model::SomethingCollection: If "Application::Model::Something" is a valid model class, then it creates a subclass of Jifty::Collection whose "record_class" is "Application::Model::Something".
Application::Notification: An empty class that descends from Jifty::Notification.
Application::Notification::Something: The class loader will search for a plugin Plugin such that Plugin::Notification::Something exists. It will then create an empty class named Application::Notification::Something that descends from Plugin::Notification::Something.
This allows an application to customize the email notification sent out by a plugin as long as the plugin defers to the application version of the class.
Application::Record: An empty class that descends from Jifty::Record is created.
Application::Upgrade: An empty class that descends from Jifty::Upgrade.
Application::View: An empty class that descends from Jifty::View::Declare.

return_class CODE

A helper method; takes CODE as a string and returns an open filehandle containing that CODE.

require

Loads all of the application's Actions and Models. It additionally "require"'s all Collections and Create/Update actions for each Model base class --- which will auto-create them using the above code if they do not exist on disk.

require_classes_from_database

Jifty supports model classes that aren't files on disk but instead records in your database. It's a little bit mind bending, but basically, you can build an application entirely out of the database without ever writing a line of code(*).

* As of early 2007, this forward looking statement is mostly a lie. But we're working on it.

This method finds all database-backed models and instantiates jifty classes for them it returns a list of class names of the models it created.

require_views

Load up $appname::View, the view class for the application.

models

Accessor to the list of models this application has loaded.

In scalar context, returns a mutable array reference; in list context, return the content of the array.

stringify

ClassLoaders stringify as "Jifty::ClassLoader(base class name)"

DESTROY

When the ClassLoader gets garbage-collected, its entry in @INC needs to be removed.

autogenerated PACKAGE

Returns true if the package was autogenerated by a classloader.

WRITING YOUR OWN CLASSES

If you require more functionality than is provided by the classes created by ClassLoader (which you'll almost certainly need to do if you want an application that does more than display a pretty Pony) then you should create a class with the appropriate name and add your extra logic to it.

For example you will almost certainly want to write your own dispatcher, so something like:

 package MyApp::Dispatcher;
 use Jifty::Dispatcher -base;

If you want to add some application specific behaviour to a model's collection class, say for the User model, create UserCollection.pm in your applications Model directory.

 package MyApp::Model::UserCollection;
 use base 'MyApp::Collection';