"Pruning" an xml "tree" based on nodes' ids

[Bourne, Robert]

All,

I am trying to prune an xml tree based on known ids for the nodes in that tree.

For example in the following code:

<tree ID="1">
                <branch ID="1">
                                <branch ID="4">
                                                <branch ID="8">
                                                                <leaf ID="15" />
                                                                <leaf ID="16" />
                                                                <leaf ID="25" />
                                                </branch>
                                </branch>
                                <branch ID="6">
                                                <branch ID="7">
                                                                <leaf ID="15" />
                                                </branch>
                                </branch>
                </branch>
                <branch ID="2">
                                <branch ID="13">
                                                <branch ID="14">
                                                                <branch ID="16">
                                                                                <leaf ID="18" />
                                                                </branch>
                                                </branch>
                                                <branch ID="65">
                                                                <branch ID="15">
                                                                                <leaf ID="25"/>
                                                                </branch>
                                                                <branch ID="166">
                                                                                <leaf ID="25" />
                                                                </branch>
                                                </branch>
                                </branch>
                </branch>
</tree>

If I know that I am ultimately after leaf with the ID of 15.  However, I also need the ancestor nodes that led me to that leaf.  I will know those IDs as well.  For example if I know that I'm in tree id 1 and the branches I took in order are 1,4,8, how can show a pruned xml tree where the final result is:

<tree ID="1">
                <branch ID="1">
                                <branch ID="4">
                                                <branch ID="8">
                                                                <leaf ID="15" />
                                                </branch>
                                </branch>
                </branch>
</tree>


I have been able to prune in to this:

<tree ID="1">
                <branch ID="1">
                                <branch ID="4">
                                                <branch ID="8">
                                                                <leaf ID="15" />


                                                </branch>
                                </branch>
                                <branch ID="6">
                                                <branch ID="7">
                                                                <leaf ID="15" />
                                                </branch>
                                </branch>
                </branch>
</tree>

But the problems comes in the fact that I don't know how many levels of branches there will be before I finally reach the leaf that I'm after.  It seems like I need to work backwards starting at the leaf and prune based on the ids that I have, but I can really see a way to do that.

Any suggestions would be greatly appreciated.

Regards,

Bob
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://x-query.com/pipermail/talk/attachments/20090909/0688c0bf/attachment-0001.htm