The second tutorial about the Issue Tracker Flex Application is online. This one is about Getting Typed Objects from Rails using [RemoteClass]. I asked him in de in the comments what the advantages are of VO’s and mapping them with Ruby:

Advantages of VOs:

If used typed VOs then you have control over the definition of the
objects that you are working with. You can control what interfaces they
implement, which properties are [Bindable], what methods they have, etc.

Using the VO design pattern as a convention will make it easier for others to understand your code.

Steven Webster (Cairngorm’s author) describes some other benefits in his ariticles about Cairngorm. Go to: http://www.adobe.com/devnet/flex/articles/cairngorm_pt2_03.html and scroll down to ‘Introducing the Value Object / Data Transfer Object Pattern’

Advantage of mapping with WebORB:

If you decide that you want to use VOs, then the advantage to using
mapping with WebORB is that you do not have to manually convert the
untyped objects that your service calls would normally return to your
typed VOs.

Disadvantage:

The disadvantage to this approach is that it ties you to a back-end
that implements mapping with the [RemoteClass] metadata tag. So if you
want to switch back-ends you will either have to choose another that
implements this functionality, or you will have to write code to do
manually do the conversion.

Thank you Derrek, for this explaination!

technorati tags:weborb, flex, cairngorm, design, patterns, VO, DTO

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