Implement the Singleton In AS3

The following example implement the Singleton In AS3 at the run-time.I don’t know if there is some other way to implement the Singleton in Compile-time.

 

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Strict Singletons in AS 3.0

With As 3.0 conforming to ECMA there you can no longer have private constructors which makes creating strict singletons a little bit more tricky. If I write a singleton, I want it written in a way that only a single instance can be created and if someone makes a mistake and tries to create an instance without using getInstance() an error will be thrown. This is a little workaround me and Rich came up with.

package{	public class Singleton	{		private static var instance:Singleton;		private static var creatingSingleton:Boolean = false;				public function Singleton()		{		if( !creatingSingleton ) throw new Error( “Singleton and can only be accessed through Singleton.getInstance()” );		}				public static function getInstance():Singleton		{					if( !instance )			{				creatingSingleton = true;				instance = new Singleton();				creatingSingleton = false;			}					return instance;		}	}}