<data>
<value>1</value>
</data>

Now imagine if V2 of the file added an attribute

<data>
<value type=”number”>1</value>
</data>

It’d be great if you opened that second file with the V1 software and then saved it again, it would preserve the stuff it didn’t understand. Unfortunately that’s not how I usually write my value objects. Usually I do something like:

public class ValueObject{public var value:Number;public static function fromXML( xml:XML ) : ValueObject{var v:ValueObject = new ValueObject();v.value = xml.value;}

public function toXML(  ) : XML{var xml:XML = <data>;xml.value = value;return xml;}}

As you can see, anything in the file that it doesn’t understand is lost. But what if we followed a facade pattern for our data objects and did something more like this:

public class ValueObject{protected var source:XML;

public static function fromXML( xml:XML ) : ValueObject{v.source = xml;}

public function toXML() : XML{return source;}

public function get value() : Number {return source.value;}public function set value(val:Number) : void {source.value = val;}}

They both have the exact same API, but the second one will preserve XML attributes (or even nodes) that it doesn’t understand.

What about AMF based projects, especially when passing rich objects with a Red5 server? I know there’s a pretty seamless mechanism in place if properties aren’t known, but how do you get those unknown properties back to the server?

What other solutions or best-practices do other people follow for solving this issue?

Rogue Development – The “dumping ground” for any interesting projects I work on.
http://www.rogue-development.com/

This site is kind of neat. It consists solely of XML and XSLT documents. The XML is transformed by the XSLT on the client side (so it only works in semi-modern browsers) and is formatted by a css stylesheet. If I had cared about supporting more browsers, I could have done the XSLT conversion on the server side, but I don’t. You can view-source on any page to see the XML, and you can check out these links for the XSLT and css pages:

CSS
XSLT

You’re free to use them, modify them, etc on your site if you wish, just drop me a note letting me know. I like to see what other people do.

Someday, I might write a Flex interface for reading the XML content. Or even better, I wonder if it’s relatively easy to create a flex app to author the XSLT documents.

Marc-Hughes.com – My personal “fun” website.
http://www.marc-hughes.com/

The front page is flash, but the rest of the site is the same XSLT as rogue-development with a different css sheet to format it.