PureMVC Pipeworks Singleton vs Multiple-Instance Modules

Sometimes you only want one instance of a module created. We'll call this type of module a singleton module.

Sometimes you might want to be able to create multiple instances of a module. We'll just call this a multiple-instance module.


Take a look at the Pipeworks demo and note how the app uses the LoggerModule and PrattlerModule.

We see there is only one instance of LoggerModule for the whole app, but we can create many instances of the PrattlerModule.

First, here is the link to the Pipeworks source.

Below are the differences between singleton and multiple-instance modules:



LoggerModule - a singleton module

-LoggerModule constructor uses LoggerModule.NAME (static String) as LoggerModule.ApplicationFacade's multiton key
-LoggerModuleMediator uses LoggerModuleMediator.NAME (static String) as Shell.Mediator's name
-LoggerModuleMediator registered, pipes connected on application startup



PrattlerModule - a multiple-instance module

-PrattlerModule constructor uses PrattlerModule.moduleID (unique ID created from auto-incrementing static counter) as PrattlerModule.ApplicationFacade's multiton key
-PrattlerModuleMediator uses PrattlerModule.getID() as Shell.Mediator's name
-PrattlerModuleMediator registered using a command, pipes connected inside command.


Below are the pertinent functions PrattleModule used to generate and retrieve moduleID:


public function getID():String
{
return moduleID;
}

private static function getNextID():String
{
return NAME + '/' + serial++;
}

private static var serial:Number = 0;

private var moduleID:String = PrattlerModule.getNextID();