[flexcoders] Re: Singletons - Best Practices

[andrii_olefirenko]

i don't know about best practices but it's quite easy to implement
package test
{
        import flash.utils.Dictionary;
        
        public class SingletonManager
        {
                private static const instances:Dictionary = new Dictionary;
                
                public static function getInstance(clazz:Class):Object
                {
                        if (!instances[clazz])
                        {
                                instances[clazz] = new clazz;
                        }
                        return instances[clazz];
                }

        }
}

Also you could take a look at slightly complex implementation in Flex
- mx.core.Singleton

Also you would probably need to force users of your class not to use
public constructor. 
It could be easy done with following (extract)

private static var iExists:Boolean;
public function MyClass()
{
 if (iExists)
 {
  throw new Error("My only instance already exists!");
 }
 iExists = true;
}


Regards,
Andrii Olefirenko


--- In flexcoders@yahoogroups.com, "Dominic Pazula" <[EMAIL PROTECTED]> wrote:
>
> I'm attempting to write singleton manager for my application.  I've 
> seen numerous ways for this to be done.  I traced through how the 
> BrowserManager and the PopUpManager are implemented.  (For the record, 
> I tried, and failed, to copy how BrowserManager is implemented).
> 
> Does anyone know what the best practices are on creating this type of 
> class?  Any gotchas to look out for?
> 
> Thanks
> Dominic
>