Adrian Aioanei

Create Combined Java/Flex project in Flex Builder

Adrian Aioanei — Wed, 23 Apr 2008 12:37:21 +0000

One of the new features in Flex Builder 3 is that you can create a combined Java/Flex project. This feature was added to help developers who code on both server side and client side parts for a project. Also it really helps development by keeping all code together for a specific project and also there is no need for multiple IDEs, like Eclipse + Flex Builder or NetBeans + Flex Builder.

We will create not only a combined Java/Flex project but a LCDS (LiveCycle Data Services) enabled project. Prerequisite for this would be an already installed server (we will go with Tomcat) that you will need to use when creating an LCDS project.

First of all you will need the Web Tools Platform (WTP) plugin installed. To install it go to Help > Software Updates > Find and Install, select “Search for new features to install” and click Next. Click on “New Remote Site”, insert a name for the site (ex. WTP) and in the URL input insert “http://download.eclipse.org/webtools/updates/”. Click on and the new remote site should be listed on the “Sites to be included in search”. Select the site and click Finish. The list of site mirrors will appear, select one of them and click OK. After the search is complete select all features to be installed. You should have something like this:

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Sending extra data in Java Exceptions to Flex Clients

Adrian Aioanei — Tue, 22 Apr 2008 13:05:15 +0000

When building Java services there is always need for handling exceptions thrown by all kind of sources. Wether those are ConstraintViolationException thrown by wrong database queries, NullPointerException thrown by wrong data manipulations or any other exceptions, all of them should end up handled in the Flex application calling the services.
One wrong usage of data transfer between client and backend services is when no matter what happens on the services, all exeptions are handled on the service and the client is basically listening only for the result method. Lets take a user management service for example. One method should be registerUser. The wrong usage would be that this method returns an generic object, if the register succeeded then it will return a User class (User class is mapped between Flex and Java using [RemoteClass] metadata in Actionscript) and if it fails then it will return an object with some messages and extra data in it. A better alternative to this is by using Java Exceptions, that are anyway handled in the services.

First, a custom exception need to be build, as in this example:

package com.myproject.exceptions;

public class UserServiceException extends Exception

{

    private static final long serialVersionUID = 1L;

    private String customMessage;

    public UserServiceException( String customMessage )

    {

        this.customMessage = customMessage;

    }

    public String getCustomMessage()

    {

        return customMessage;

    }

}

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Adobe AIR released for Linux

Adrian Aioanei — Mon, 31 Mar 2008 09:31:31 +0000

Adobe AIR becomes truly cross platform with the release of Linux version on Adobe Labs.

AIR 1.0 is available for Windows and Mac OS since last year, the Linux version was delayed due to core Flash Player issues on Linux platform. Starting today Linux developers out there can take the Adobe AIR Alpha version for a ride and also ask questions and share feedback in the Adobe AIR for Linux Labs forum.

Another big announcement is that Adobe is getting more and more involved into the Linux world, now collaborating with the Linux Foundation (LF), a non-profit organization focusing on development of Linux, to ensure that all Adobe RIA technologies are compatible with Linux platform.

For more release notes on Adobe AIR on Linux go here.

Adobe Photoshop Express Released

Adrian Aioanei — Thu, 27 Mar 2008 20:37:39 +0000

Adobe Photoshop Express was released today as a public beta. Adobe Photoshop Express is a free online Rich Internet Application aiming at storing and editing digital photos, taking the online image editing a step further. You can apply all sorts of cool effects like distort, sketch, tint, hue to you images then store them on albums and publish to the world.

Although its beta version it looks great so far but thing is that its fully available only for US citizens for now. Peoples outside US can go for a test drive. As with all beta products you can also give feedback.

Rumors are that an AIR version will be available soon to take the RIA on the desktop. Cool.

[Update] You can go for an account even if you are outside the US, you just select United States in the Country field (dooh). But keep in mind that the server is in Los Angeles so you might expect some delays when trying all those cool features.

Flex Tip 7: Using Deferred Instantiation

Adrian Aioanei — Wed, 26 Mar 2008 20:02:21 +0000

When you are using MXML containers and declare the children as MXML tags inside the component, there is a possibility to not load all child components at instantiation, possibility known as “deferred instantiation”. That is, the instantiation is deferred by an amount of time depending on creationPolicy property of Container class. This is the property that sets the rules in creation of child components:

- a creationPolicy of ContainerCreationPolicy.AUTO means that the container delays creating some or all descendants until they are needed. This policy produces the best startup time because fewer UIComponents are created initially.

- a creationPolicy of ContainerCreationPolicy.QUEUED means that the container is added to a creation queue rather than being immediately instantiated and drawn. When the application processes the queued container, it creates the children of the container and then waits until the children have been created before advancing to the next container in the creation queue.

- a creationPolicy of ContainerCreationPolicy.NONE means that the container creates none of its children. In that case, it is the responsibility of the MXML author to create the children by calling the createComponentsFromDescriptors() method.

The version we are interested in is ContainerCreationPolicy.NONE when instantiation of children is let it developer’s hand. So lets go ahead and create a simple component:

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Adobe Developer Week

Adrian Aioanei — Sat, 22 Mar 2008 18:53:29 +0000

If you didn’t know, from March 24 to March 28 there is Adobe Developer Week, week that consists of 20 events covering all development areas including AIR, Flex, Flash, Mobile, ColdFusion and Dreamweaver. All events will be hosted on Adobe Connect sessions and if you miss the live ones don’t worry, all events will be recorded and available online within 5 business days.

Go here and register for the event you are interested in. I’m registered to the following sessions:

Introduction to Adobe Blaze DS

Adobe AIR Local Data Storage Options With Emphasis on Using Embedded SQL Databases

Flex and Java – Tying the Knot!

Flex Data Services

AIR Native Drag and Drop

Flex Architecture

To register you need your Adobe.com membership login and password. If you need to create a membership, or do not remember your login and password, you’ll need to go to Adobe.com membership page.

Don’t miss it.

Flex Tip 6: Garbage Collection in Flex

Adrian Aioanei — Mon, 17 Mar 2008 13:34:11 +0000

One of the hot-spots in Flash platform is related to memory, how is it distributed inside the runtime environment, memory leaks and of course garbage collection. The way that memory allocation takes place inside Flash is by instantiation, every time a new Object is created, a memory block is created for it. The problem comes when that Object is freed because its block will not always be re-used by the next allocation. The simple “freed” action wont mark it unused, only Garbage Collection will mark it unused, GC that is ONLY triggered by allocations meaning that if there are no instantiations in the application, its memory usage will not change.

Now how GC works in its deeps depends a lot on how you build your application, if you remove event listeners from deleted objects, if you re-use your already created object instances and so on. Garbage Collection IS NOT PREDICTABLE, it cant say that your application is bullet proof, that is not leaking memory.

One trick that you can use to force a garbage collection in your Flex application is by using this statement:

try

{

      var lc1:LocalConnection = new LocalConnection();

      var lc2:LocalConnection = new LocalConnection();

      lc1.connect( "gcConnection" );

      lc2.connect( "gcConnection" );

}

catch (e:Error) {}

The simple instantiation of LocalConnection will trigger a full garbage collection, a nice solution you can use in your application.
Even using this doesn’t assures use that you don’t have memory leaks inside the app, it really depends on how you write your code, if you write it with GC in mind.

As a reassurance in this matter, next releases will have memory diagnostic tools helping you find any memory leaks your app might have. Until then use the tip with LocalConnection and also there can be made automated test sequences in ActionScript that tests the application without human intervention (like faking mouse or keyboard events).

Flex Tip 5: Using Runtime CSS

Adrian Aioanei — Thu, 24 Jan 2008 18:02:41 +0000

On large scale projects that will be deployed on more than just one location it is a constant need for re-skinning the application. This applies mostly to “embedding” projects, that is projects that will need to be integrated (embedded) into an already done site, with a custom template.

First solution would be duplicate the project each time a new theme is required. But this will end up in a bad situation where in one instance a bug is spotted and it will have to be fixed in all of them, making the nightmare of on any programmer.

Second solution adds in scene css, using them as compile-time css. This means that all styles applied to components are stored into an external .css file that is embedded in the application at compile time. But eventually this will be a problem too. On the bug situation mentioned above, using compile time css will end up in compiling the project for each desired theme, one at a time. Not a very good situation either.

And here is where the fun part begins. Using runtime css you will be able to build and deploy the application once and then change the css files on the server each time you need a different skin. This goes without changing anything in the code and when the bug problem appears it’s just a matter of fixing and uploading the app again.

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Flex Tip 4: Export Release Build (Flex Builder 3)

Adrian Aioanei — Wed, 23 Jan 2008 18:16:23 +0000

If you are creating new project in Flex Builder 3 you will notice that there is no “bin” folder where the .swf, .html and .js files are stored. Instead you get a “bin-debug” folder with the files. This is because Flex Builder 3 threats the project by default as a debug one, running the .swf from “bin-debug” folder.

When moving a project from Flex Builder 2 to Flex Builder 3 you will get a strange feeling that the size of the .swf for the application gets larger in FB3 that in FB2. Its just a feeling, what FB is doing is compiling the debug version any time you Run or Debug the project.

To obtain the non-debug version of your application (also knows as release version) you will have to go to Project / Export Release Build. In the popup the “Export to Folder” input is already filled up with “bin-release”, thats where the release version of your project will end up after clicking Finish.

If you compare the size of both .swf from “bin-debug” and “bin-release” you will see the difference. The one from “bin-release” is the one that should be uploaded to the site or wherever you need it.

Another small and helpful tip for day-to-day work with Flex.

Adobe AIR Revolution

Adrian Aioanei — Tue, 22 Jan 2008 17:50:13 +0000

Adobe AIR, currently in beta stage, is a new software from Adobe that lets developers using HTML, Ajax, Flash and Flex build and deploy rich internet application on their own desktop. Although AIR finalization is in progress, there are many applications out there built on top of it, showing all the cool capabilities of the software. I will list some of the ones available for the public.

1. Adobe Media Player

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