Robin van Emden's blog on things Drupal
Parsing a taxonomy tree in Flash Actionscript 3
By Robin on 19 Jun 2011
I often need to integrate Flash AS3 elements into Drupal projects. Something made very easy by the great AS3 Drupal Proxy and Drupal AMFServer module from the guys at DPDK. Of the structures that are returned by the default Services module, the taxonomy tree needs a little more processing than most.
In order to parse the taxonomy tree in my AS3 frontend code I use the recursive function shown below (here on its own, stripped a bit - by default part of a DrupalUtils helper class & returning a as3ds tree).
As an aside: because Actionscript 3.0 primitive types like ints are immutable (in effect passing-by-value), I wrap the variable that keeps track of the callee level in a separate Reference class (enabling passing-by-reference) to forgo global variables, a no-no in recursive functions.
package org.drupal.amfserver
{
...
public class DrupalNewsServer extends MovieClip
{
...
public function DrupalNewsServer()
{
...
proxy = new DrupalProxy(endpoint,DrupalProxy.VERSION_7);
proxy.setHandler("taxonomy_vocabulary", "getTree", onTreeResult, onStatus);
sequence.add(new CallBackTask(proxy.setRemoteCallId, "taxonomy_vocabulary.getTree(2)"));
sequence.add(new DrupalInvokeTask(proxy, "taxonomy_vocabulary", "getTree", 2));
sequence.execute();
}
private function onTreeResult(data : DrupalData):void
{
parseDrupalTree(data.getData());
}
/********************/
/* recursive parser */
/********************/
public function parseDrupalTree( obj : *, level : int = 0, parentTid: int = 0,
main_level:Reference=null):void
{
if (!main_level)
{
main_level = new Reference();
main_level.value = 0;
}
// tabs for testing by trace
var tabs:String = "";
for (var i : int = 0; i < level; i++)
{
tabs += "\t\t";
}
var level_array = new Array();
for (var prop:String in obj)
{
if (obj[prop].depth == level
&& obj[prop].parents.indexOf(String(parentTid)) != -1
&& level_array.indexOf(obj[prop].tid) == -1)
{
if (level>main_level.value)
{
// do things on down tree
level_array.splice(0);
}
if (level<main_level.value)
{
// do things on up tree
level_array.splice(0);
}
level_array.push(obj[prop].tid);
// trace
trace( tabs + "[" + obj[prop].tid + "] " + obj[prop].name + " level " + level);
main_level.value = level;
parseDrupalTree( obj, level + 1, obj[prop].tid, main_level);
}
}
}
}
}
class Reference {
public var value:*;
}The result is a nicely indented taxonomy tree:
[1] Milieu level 0
[7] Subthema 3 level 1
[8] Subthema 4 level 1
[3] Scholen level 0
[7] Subthema 3 level 1
[9] Subthema 5 level 1
[4] Educatie level 0
[5] Subthema 1 level 1
[7] Subthema 3 level 2
[6] Subthema 2 level 1
[2] Vrouwen level 0
[10] Subthema 6 level 1When used with as3ds tree structure this translates for example into the following (AS3 application screenshot):
Comments
Hi Robin, nice read and
By rolf (not verified) on 25 Oct 2011 at about 18:24.Hi Robin,
nice read and thanks for the props. any reason why you do not use the tree structure from the dpdk package also? I actually made those datastructures to provide a more comprehensive api than the polygonal one (which is an
excellent and fast implementation by the way).
greetz!
Hi Rolf, I didn't use the
By admin on 29 Oct 2011 at about 16:21.Hi Rolf,
I didn't use the tree structure from the dpdk package because I didn't know one existed. Great that it provides a more comprehensive API! I will look it up and update my post to reflect my findings.
Thanks!