Creating custom class instances for XML nodes

Question

Hi guys,
I'm trying to load an external XML document in my application
and create an instance of a custom class for each node in the XML
based on the value of some of their elements. The instances created
will eventually end up in a DataGrid by the way. The problem I'm
having is there seems to be many ways of doing small parts of this
and I have no idea how to make them all gel. Initially I'm using
HTTPService to load the XML file but I've seen people just use an
XML object. Then, after that, I initially set the loaded XML to an
ArrayCollection but others have used XMLList or XMLListCollection.
I've no idea what's the best way to do this.
Eventually, when I've created all of these instances by
looping over the XML and creating them how will I make them
bindable to the data grid? I'm guessing I'll have to group them
somehow...
Any help would be greatly appreciated. Thanks

Answer 1

Hey Tracy,
That is exactly what I was talking about in a previous post
you replied to
http://www.adobe.com/cfusion/webforums/forum/messageview.cfm?catid=585&threadid=1344350
Anyhow, Below is some code I created to do what your saying
somewhat dynamically. The idea being you can have many different
object types that you may want to populate with data from XML. In
my case I am using e4x as the result type from my web services. At
present I have about 6 different classes that call this function.
I'd love to get some opinions on the function. Good bad or
???? Any improvements etc????
package . . . .
import flash.utils.describeType;
import flash.utils.getDefinitionByName;
import flash.utils.getQualifiedClassName;
import mx.utils.ObjectUtil;
* Utility class to convert xml based Objects to class
instances.
* Takes a value object as the destination and an xmlList of
data
* Look through all the items in the value object. Note we
are using classInfo..accessor since
* our objects are bound all variables become getter /
setter's or accessors.
* Also note, we can handle custom objects, arrays and
arrayCollections.
* History
* 03.11.2008 - Steven Rieger : Created class
public final class XMLToInstance
public static function xmlToInstance( destinationObject :
Object, sourceXMLList : XMLList ) : void
// Get the class definition in XML, from the passed in
object ( introspection so to speak )
var classInfo : XML = describeType( destinationObject );
// Loop through each variable defined in the class.
for each ( var aVar : XML in classInfo..accessor )
// If this is String, Number, etc. . . Just copy the data
into the destination object.
if( isSimple( aVar.@type ) )
destinationObject[aVar.@name] = sourceXMLList[aVar.@name];
else
// Dynamically create a class of the appropriate type
var className : String = aVar.@type;
var ObjectClass : Class = getDefinitionByName( className )
as Class;
var newDestObject : Object = Object( new ObjectClass());
// If this is a custom type
if( isCustomType( className ) && ObjectClass != null
// Recursively call itself passing in the custom data type
and the data to store in it.
// I haven't tested nested objects more than one level. I
suppose it should work.
// Note to self. Check.
xmlToInstance( newDestObject, sourceXMLList[aVar.@name] );
else
// Must be some sort of Array, Array Collection . . .
if( ObjectClass != null )
var anXMLList : XMLList = new XMLList(
sourceXMLList[aVar.@name] );
for each( var anItem : XML in anXMLList )
// I'm sure there are more types, just not using any of them
yet.
if( newDestObject is Array )
newDestObject.push( anItem )
else
newDestObject.addItem( anItem );
// Add the data to the destination object. . . .
destinationObject[aVar.@name] = newDestObject;
} // end function objectToInstance
public static function isSimple( dataType : String ) :
Boolean
* This function is pretty self explanatory.
* Check to see if this is a simple data type. Did I miss
any?
* History
* 03.11.2008 - Steven Rieger : Created function
switch( dataType.toLowerCase() )
case "number":
case "string":
case "boolean":
return true;
return false;
} // end isSimple
public static function isCustomType( className : String ) :
Boolean
* This function is pretty self explanatory.
* Check to see if this is a custom data type. Add them here
as you need. . .
* History
* 03.11.2008 - Steven Rieger : Created function
var aClassName : String = className.replace( "::", "."
).toLowerCase();
aClassName = aClassName.substr( aClassName.lastIndexOf( "."
) + 1, aClassName.length - aClassName.lastIndexOf( "." ) );
switch( aClassName )
case "ndatetimevo":
case "expenselineitemvo":
return true;
return false;
} // end isCustomType
} // end class
} // end package