This function serialises the entire object into an array of bytes and then deserialises it back into a completely new instance of that class.

But while deserialing it must have ‘type’ information of the Object, otherwise  the created object might have all of the properties of a class instance but it will not be a true class instance.

Here is the way to add Type information

• Using the [RemoteClass] metadata tag.
• Using the registerClassAlias() method.

Way to use [RemoteClass]

package

{

    [RemoteClass]

    public class Example

    {

        public function Example()

        {

         }

    }

}

var ex:Example= new Example();

var o:Object = ObjectUtil.copy(example);

Way to use resisterClassAlias()

 registerClassAlias( ”Example”, Example ); 

var copy:Example = Example( ObjectUtil.copy( example ) );

For more information have a look at this blog

http://www.darronschall.com/weblog/2007/08/on-transient-objectutilcopy-and-casting.cfm

Issue :

Fault Code : Server.Processing.DuplicateSessionDetected.

Error Message : Detected duplicate HTTP-based FlexSessions, generally due to the remote host disabling session cookies. Session cookies must be enabled to manage the client connection correctly.

Reproducing steps :

1. Open your application in two different tabs (basically these two tabs will share same session) and then close one tab.

2. Do any action (related to server interaction ) in other tab..then u can see the exception.

Solution :

Actually you find so many solutions for this problem just like writing custom adaptor etc.

But, my suggession if you are not really concern with BlazeDS version, roll back to BlazeDS 3.0.0.544.

Easy MVC (Basic framework behind Cairngorm)
Flex Performance compare to other technologies.

By using Modular application architecture you can split your application in to pieces (SWF’s), and you can load particular piece (SWF) dynamically at runtime.

This type of architecture increases start-up performance.

Note: Modules can’t run it self just like application.

Important Classes in Module api :

1. Module -> Base class for MXML based modules

2.ModuleBase -> Base class for Action Script based modules

3.ModuleManager -> Singleton, centrally manages dynamically loaded Modules (ModuleManager provides a low level api for handling modules than ModuleLoader class)

4.ModuleLoader -> Loads modules dynamically at run-time.

5.IModuleInfo ->Interface, A handle for module, provides information such as url, loaded state etc.

6.ModuleEvent -> Will dispatch events during module lifecycle.

Creating Modules with MXML and ActionScript :

MXML:

<mx:Module xmlns:mx=”http://www.adobe.com/2006/mxml” width=”100%” height=”100%”

……….

</mx:Module>

Action Script:

import mx.modules.ModuleBase;

public class SampleModule extends ModuleBase {

…

}

If your module does not include any framework code, you can create a class that extend the ModuleBase class. If you use the ModuleBase class, your module will typically be smaller than if you create a module that is based on the Module class because it does not have any framework class dependencies.

Loading Modules : Both ModuleManager, ModuleLoader can be used to load the modules

ModuleManager :

ModuleManager is a singleton class, primarily used via static method ‘getModule()’. The ‘getModule()’ method will accepts a url argument and returns an IModuleInfo instance.

var moduleInfo:IModuleInfo = ModuleManager.getModule( “SampleModule.swf” );

moduleInfo.addEventListener( ModuleEvent.READY, onModuleReady );

moduleInfo.load();

When a Module is loaded and ready, to get an instance of loaded module…

protected function onModuleReady( moduleEvent:ModuleEvent ):void {

var moduleInfo:IModuleInfo = moduleEvent.module;

var sample:SampleModule = moduleInfo.factory.create() as SampleModule;

}

ModuleLoader :

ModuleLoader ensures that only a single copy of Module SWF transfererd over the network by using ModuleManager.

Action Script :

var loader:ModuleLoader = new ModuleLoader(“SampleModule.swf” );

loader.addEventListener( ModuleEvent.READY, handleModuleReady );

loader.load();

MXML :

<mx:ModuleLoader url=”SampleModule.swf” progress=”handleModuleProgress(event); ready=”handleModuleReady(event);” error=”handleModuleEvent(event);” />

ModuleEvent :

ModuleEvent types : PROGRESS, READY,ERROR,UNLOAD,SETUP

ModuleEvent properties : module:IModuleInfo, bytesLoaded, bytesTotal

Passing a query string data to Modules :

Query string parameters (e.g. ?param=value) can be appended to the URL used to load a Module

<mx:ModuleLoader url=”SampleModule.swf?firstName=Sri&lastName=Velli” />

The query string can be accessed in Module using ‘loaderInfo’ property. See the example below how to access and parse the loader string

var url:String = this.loaderInfo.url.toString();

// remove everything before the question mark, including the question mark

var regexQuery:RegExp = /.*\?/;

var queryString:String = url.replace( regexQuery, “” );

// create an array of name=value pairs

var paramArray:Array = queryString.split( “&” );

// put the names value into an object

var paramObject:Object; var param:String;

var pair:Array;

for each( param in paramArray ) {

pair = param.split( “=” );

// name = value

paramObject[ pair[0] ] = pair[1];

}

Modules and Parent Application, Modules and Modules Communication

Modules can access the methods and properties of parent application by using the parentApplication property. U can access properties and methods of other modules through the parentApplication by using a ModuleLoader’s child property.

parentApplication.module2.child.hasOwnProperty(“property”);

parentApplication.module2.child.somePreperty;

parentApplication.module2.child.someMethod();

Coming to BlazeDS, an open source Java implementation of AMF (Action script Message Fromat) based messaging, allows front end applications easily connect with existing methods on POJOs, Spring Services or EJB. it works with wide range of Java based servers including Tomcat, Weblogic, Websphere, Jboss etc..

Ready use version of BlazeDS with Tomcat is available here  

Here is the high level steps how to integrate Flex and Java by using Remote Object

1. Downlaod and install BlazeDS from here  

2. Assume you have your businees layer implemneted and deployed in server, and u can create a POZO class  to expose methods that you want to access from Flex applications.

3.Copy the ‘flex’ folder from blazeds.war\WEB-INF to your WEB-INF folder . This folder contains the configuration files needed by BlazeDS. In remote-config.xml file add a new remote destination pointing to POZO class that exposes the business logic.

              <destination id=”remoteEx”>

                         <properties>

                                     <source>com.ex.SamplePOZO</source>

                                     <scope>application</scope>

                         </properties>

              </destination>

      the root tag for remote-config.xml will looks like this

      <service id=”remoting-service” class=”flex.messaging.services.RemotingService”/>

      This RemoteClass will handles the all calls made to all destinations by invoking the appropriate adaptor. The adaptor is responsible for invoking methods on the Java Class based on source tag and returns the result. If the destination doesn’t have specific adaptor, the default adaptor from remote-config.xml will be used.

4. Flex provides Remote Object  component, which allows you to call methods on Java class associated with the corresponding destinations.

      <mx:RemoteObject id=”remoteService”  showBusyCurser=”true” destination=”remoteEX”>

                 <mx:method name=”methodname1″ />

                 <mx:method name=”methodname2″ />

     </mx:RemoteObject>

5. Everything else is transperent from the user’s point of view (including the conversion between action script and java objects and serialization).

     Suppose if your POZO class is returning Java Value Object then you need to map it to corresping Action Script Value Object by using [RemoteClass] metadata such as

      [RemoteClass(alias="com.ex.SampleVO")]

6.The folder name ‘lib’ under blazeDs.war\WEB-INF contains all the jar files needed by blazeDs, copy all these jar files to your WEB-INF\lib folder.

7.Update the channel definitions in services-config.xml to point to appropriate address and port number

     server.name, server.port

8. Add the following entries to your web.xml (taken from blazeDS ,  web.xml)

<!– Http Flex Session attribute and binding listener support –>
<listener>
   <listener-class>flex.messaging.HttpFlexSession</listener-class>
</listener>
<!– MessageBroker Servlet –>
<servlet>
   <servlet-name>MessageBrokerServlet</servlet-name>
   <servlet-class>flex.messaging.MessageBrokerServlet</servlet-class>
   <init-param>
      <param-name>services.configuration.file</param-name>
      <param-value>/WEB-INF/flex/services-config.xml</param-value>
   </init-param>
   <init-param>
      <param-name>flex.write.path</param-name>
      <param-value>/WEB-INF/flex</param-value>
   </init-param>
   <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
   <servlet-name>MessageBrokerServlet</servlet-name>
   <url-pattern>/messagebroker/*</url-pattern>
</servlet-mapping>

That’s it. You are done…

basically this folder contains the following files
* AC_OETags.js – A JavaScript source file used by client to detect and embed the Flash Player
* playerProductInstall.swf – This implements the Flash Player Express Install mechanism which comes into play if the client does not have the required player
* index.template.html -HTML template that is used by the FlexBuilder to generate the wrapper html for all the application files in your project.

You can refer this post for more about index.template.html

http://www.morearty.com/blog/2006/12/11/changing-the-filenames-in-flex-builder-html-templates/

Conclusions:

If you want to add event listeners to your application (just like systemManager.addEventListener(EventType, listener)), u can do this only after application was added to stage (before that stage/systemManager will be null) and we can dispatch events only in/after applicationComplete.

Here is the events firing order, have a look.

1. creationComplete
2. ADDED_TO_STAGE –> here we are adding listeners to events (So, we can dispatch this events in next steps only)
3. applicationComplete

If you want to get the server url dynamicaly…here is the code snippet

var serverUrl : String = Application.application.loaderInfo.url;
var index : int = serverUrl.indexOf(“x.swf”);
serverUrl = serverUrl.substr(0, index-1);

We can also use below code
var locationurl:String = ExternalInterface.call(“window.location.href.toString”);
var servicesUrl:String = locationurl.split(“/”)[2];

But this is not appropriate in all conditions.

x.width = stage.width * 0.5;
x.height = stage.height * 0.5;

Conclusion : Here pop up height and width are exactly 1/2 of the Application height and width.

Conclusions from what i studied…..

Higher frame rates makes your application faster (But it will cost your CPU performance).

The default frame rate for Flex is 24 frames per second (for Flash 9).  

If you want you can specify what ever you want…

Ways to specify frameRate:

              1.          <mx:Application frameRate=”60″/>

              2.          stage.frameRate = “60″

              3.          [SWF(frameRate = "60")]

                            public class Example extends Sprite {

                                      ……….

                           }

              4.         You can set as compile time argument