NotificationCenter

One common OOP pattern is Model-View-Controller where one object (the controller) is a dependant of the model. Every time the model changes it notifies all of its dependants. In this case the model has a dictionary of dependants and iterates through those.

Another common pattern is NotificationCenter wherein an object emits a notification and clients can register functions that will be executed when that notification happens.

A Server emits a \newAllocators notification when it creates new node and bus allocators which it does when it quits or boots.

NotificationCenter.notify(Server.default,\newAllocators);

You can listen for this:

NotificationCenter.register(Server.default,\newAllocators,yourself, {

// throw away all your node variables

// or stop the music

});

The Buffer class register a function to clear its info cache whenever a server restarts. The server is emiting changed messages quite often (every 0.4 secs for the status updates), and the Buffer class is only interested in boot/quit events, so this is a more lightweight system for this purpose.

*notify(object,message,args)

The object emits a message and may also pass extra args

*register(object,message,listener,action)

An interested client can register the action function for the object/message notification.

A listener may only register one action per object/message notification.

*unregister(object,message,listener)

Remove the registrations

*registerOneShot(object,message,listener,action)

After the notification has been emited and handled, automatically unregister.

*registrationExists(object,message,listener)

Simply confirms if a registration is already in place