//The document class

package

{

  import flash.display.Sprite;

  import flash.events.Event;

  import flash.events.EventDispatcher;

  public Class TestDocClass extends Sprite

  {

    private var _model:Model;

    public function TestDocClass():void

    {

      _model = new Model();

      _model.addEventListener(Model.VALUE_CHANGED, onModelChanged);

    }

    private function onModelChanged(e:Event):void

    {

      trace('The value changed');

    }

  }

}

//The model that holds the data (variables, etc) and dispatches events. Save in same folder as DOC Class;

package

{

  import flash.events.Event;

  import flash.events.EventDispatcher;

  public class Model extends EventDispatcher

  {

    public static const VALUE_CHANGED:String = 'value_changed';

    private var _someVar:someVarType;

    public function Model():void

    {

      trace('The model was instantiated.');

    }

    public function set someVariable(newVal:someVarType):void

    {

      _someVar = newVal;

      this.dispatchEvent(new Event(Model.VALUE_CHANGED));

    }

  }

}

package

{

  import flash.display.Sprite;