ApplicationDomain class

Using the ApplicationDomain class

The purpose of the ApplicationDomain class is to store a table of ActionScript 3.0 definitions. All code in a SWF file is defined to exist in an application domain. You use application domains to partition classes that are in the same security domain. This allows multiple definitions of the same class to exist and also lets children reuse parent definitions.

You can use application domains when loading an external SWF file written in ActionScript 3.0 using the Loader class API. (Note that you cannot use application domains when loading an image or SWF file written in ActionScript 1.0 or ActionScript 2.0.) All ActionScript 3.0 definitions contained in the loaded class are stored in the application domain. When loading the SWF file, you can specify that the file be included in the same application domain as that of the Loader object, by setting the applicationDomain parameter of the LoaderContext object to ApplicationDomain.currentDomain. By putting the loaded SWF file in the same application domain, you can access its classes directly. This can be useful if you are loading a SWF file that contains embedded media, which you can access via their associated class names, or if you want to access the loaded SWF file's methods, as shown in the following example:

package {    

import flash.display.Loader;   

import flash.display.Sprite;  

 import flash.events.*;   

import flash.net.URLRequest;  

 import flash.system.ApplicationDomain;

   import flash.system.LoaderContext;  

  public class ApplicationDomainExample extends Sprite     {

       private var ldr:Loader;       

public function ApplicationDomainExample()         {

           ldr = new Loader();            

var req:URLRequest = new URLRequest("Greeter.swf");            

var ldrContext:LoaderContext = new LoaderContext(false,

ApplicationDomain.currentDomain);            

ldr.contentLoaderInfo.addEventListener(Event.COMPLETE, completeHandler);

 ldr.load(req, ldrContext);             }       

private function completeHandler(event:Event):void         {  

        ApplicationDomain.currentDomain.getDefinition("Greeter");  

         var myGreeter:Greeter = Greeter(event.target.content);   

        var message:String = myGreeter.welcome("Tommy");       

    trace(message); // Hello, Tommy         }     } }









Other things to keep in mind when you work with application domains include

the following:
 
All code in a SWF file is defined to exist in an application domain.

The  current domain is where your main application runs.

The system  domain contains all application domains, including the current

domain,  which means that it contains all Flash Player classes.

All application domains, except the system domain, have an associated parent

domain. The parent domain for your main application's application domain is

the  system domain. Loaded classes are defined only when their parent doesn't

already  define them. You cannot override a loaded class definition with

a newer  definition.