Changing flat XML into nested

Question

I'm working on a tree navigation that needs to have some data provided in a nested xml format
<node label="California">
     <node label="location 1" />
     <node label="location 2">
          <node label="option 1" />
          <node label="option 2" />
     </node>
</node>
But the data that I'm getting (and probably can't change) is coming out flat:
<item>
     <id>12</id>
     <label>California</label>
</item>
<item>
     <id>15</id>
     <label>location 1</label>
     <parent>12</parent>
</item>
<item>
     <id>17</id>
     <label>location 2</label>
     <parent>12</parent>
</item>
<item>
     <id>33</id>
     <label>option 1</label>
     <parent>17</parent>
</item>
<item>
     <id>70</id>
     <label>loption 2</label>
     <parent>17</parent>
</item>
Any suggestions on how to change that data from what I'm supplied to what I need? Is it just a brute force looping through the xml nodes a bunch of times? Or is there a clever way that I'm not seeing?

Answer 1

If you are sure about data integrity, especially ids relationships, the following is one of the ways to reposition nodes without changing general node structure. Following this logic you can restructure XML altogether.
With that said, I am not sure XML restructuring is the best way to go anyway. I feel a much better solution would be to parse XML into a more native to AS3 structure like Array, Object or Vector. I would rather create a specialized data provider class.
Example uses the following XML:
<items>
    <item>
        <id>1</id>
        <label>California</label>
    </item>
    <item>
        <id>2</id>
        <label>California location 1</label>
        <parent>1</parent>
    </item>
    <item>
        <id>3</id>
        <label>California location 1 option 1</label>
        <parent>2</parent>
    </item>
    <item>
        <id>4</id>
        <label>California location 1 option 2</label>
        <parent>2</parent>
        </item>
    <item>
        <id>5</id>
        <label>California location 1 option 3</label>
        <parent>2</parent>
    </item>
    <item>
        <id>6</id>
        <label>California location 2</label>
        <parent>1</parent>
    </item>
    <item>
        <id>7</id>
        <label>California location 2 option 1</label>
        <parent>6</parent>
    </item>
    <item>
        <id>8</id>
        <label>California location 2 option 2</label>
        <parent>6</parent>
    </item>
    <item>
        <id>9</id>
        <label>New York</label>
    </item>
    <item>
        <id>10</id>
        <label>New York location 1</label>
        <parent>9</parent>
    </item>
    <item>
        <id>11</id>
        <label>New York location 1 option 1</label>
        <parent>10</parent>
    </item>
    <item>
        <id>12</id>
        <label>New York location 1 option 1</label>
        <parent>10</parent>
    </item>
</items>
Code that parses this xml is (given the value of the xml above is assigned to var xml:XML
var parent:XMLList;
for each (var node:XML in xml.item)
    if (node.parent.toString() != "")
        parent = xml.item.(id == node.parent.toString());
        if (parent.parent.toString() == "")
            parent.@["type"] = "top";
        node.@["type"] = "child";
        parent.appendChild(node);
xml = new XML(xml.toString());
while (xml.item.(@type == "child").length() > 0)
    delete xml.item.(@type == "child")[0];
trace(xml);
Output is:
<items>
    <item type="top">
        <id>1</id>
        <label>California</label>
        <item type="child">
            <id>2</id>
            <label>California location 1</label>
            <parent>1</parent>
            <item type="child">
                <id>3</id>
                <label>California location 1 option 1</label>
                <parent>2</parent>
            </item>
            <item type="child">
                <id>4</id>
                <label>California location 1 option 2</label>
                <parent>2</parent>
            </item>
            <item type="child">
                <id>5</id>
                <label>California location 1 option 3</label>
                <parent>2</parent>
            </item>
        </item>
        <item type="child">
            <id>6</id>
            <label>California location 2</label>
            <parent>1</parent>
            <item type="child">
                <id>7</id>
                <label>California location 2 option 1</label>
                <parent>6</parent>
            </item>
            <item type="child">
                <id>8</id>
                <label>California location 2 option 2</label>
                <parent>6</parent>
            </item>
        </item>
    </item>
    <item type="top">
        <id>9</id>
        <label>New York</label>
        <item type="child">
            <id>10</id>
            <label>New York location 1</label>
            <parent>9</parent>
            <item type="child">
                <id>11</id>
                <label>New York location 1 option 1</label>
                <parent>10</parent>
            </item>
            <item type="child">
                <id>12</id>
                <label>New York location 1 option 1</label>
                <parent>10</parent>
            </item>
        </item>
    </item>
</items>