renumbering xml elements with XSLT

[csbdeady]

After reading around Google search results, and experimenting a bit I'm stuck with trying to renumber elements in an XML source via XSLT.

If I have something like:

<something uid="1" />
<something uid="2" />
<something uid="3" />

What would be the most straight-forward XSLT code to allow me to pass in a parameter to allow me to insert an element between uid's 1 and 2, giving it's uid attribute the value of "2" (ie: the same value as the element it is inserted before) and renumbering the subsequent elements' uid attributes accordingly to give me:

<something uid="1" />
<something uid="2" /> - this is the newly inserted element
<something uid="3" /> - this was formally UID="2"
<something uid="4" /> - this was formally UID="3"

Note that uid="1" remains constant, it is only uid="2" and uid="3" that get renumbered to allow for the newly inserted element.

Thanks

 

[JontyMC]

Why do the elements have to be numbered? They inherently have numbering - their position in the nodeset.

Jon

"I don't regret this, but I both rue and lament it.

 

[csbdeady]

Ahah! Good point - but if I have to ID attributes - one denoting its "unique"ness and the other its order I could have:

<something uid="1" oid="1" />
<something uid="2" oid="2" />

to start with, but later want:
<something uid="2" oid="1" />
<something uid="1" oid="2" />

To facilitate re-ordering but preserving the uniqueness (uid) I need to be able to update the oid values (ok my original post asked to update the uid - that was a typo)

The problem I have still stands though - how to insert a new element taking the oid (not uid!) of an existing one, and how to renumber the subsequent oid's?

 

[JontyMC]

I don't get why you need theses attributes. XML is not like a database. Elements are by definition unique and the order is captured inherently by the order in the nodeset.

Jon

"I don't regret this, but I both rue and lament it.

 

[csbdeady]

I need these elements because I am generating a TestSuite of TestCases in an XML file format to be played back through Compuware's TestPartner automated test tool. Each <testcase/> must have both oid and uid attributes - the uid defines the unique identifier for the TestCase - which means that we can tell people "TC number 2 failed, TC number 3 passed" etc. However the order in which the Test Cases are executed also needs defining - and this uses the oid value.

Yes one could store the data in a database, however for our purposes this would be slow and cumbersome - the reason for this is that when running an automated test we need to install the auto-test software on the test machine (which is fair enough as one can't run the test cases without such), but if I also have to install a DBMS as well then that means the machine is no longer in an appropriate test state.

Therefore the best solution is to store the Test Cases in an XML file - no special DBMS required (as the Test Cases are processed within TestPartner).

One could talk for hours on this, but I'm deviating from the point - which is how to update the oid values when inserting a new Test Case.

 

[JontyMC]

I think the easiest way is to output the nodes with oid less than the oid param, then output a new node with the uid set to the highest available + 1 and oid set to the oid param, then output the nodes with oid not less than the oid param with oid set to oid + 1. If that makes sense.

This assumes that your nodes are ordered by oid (and gives a default value for the oid to insert a node before):

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="[URL unfurl="true"]http://www.w3.org/1999/XSL/Transform">[/URL]
  <xsl:param name="oid" select="2"/>
  <xsl:template match="/">
    <root>
      <xsl:apply-templates select="root"/>
    </root>
  </xsl:template>
  <xsl:template match="root">
    <xsl:copy-of select="something[position() &lt; $oid]"/>
    <something uid="{something[not(../something/@uid &gt; @uid)]/@uid + 1}" oid="{$oid}"/>
    <xsl:apply-templates select="something[not(position() &lt; $oid)]"/>
  </xsl:template>
  <xsl:template match="something">
    <something uid="{@uid}" oid="{@oid + 1}"/>
  </xsl:template>
</xsl:stylesheet>

Jon

"I don't regret this, but I both rue and lament it.

 

[JontyMC]

By the way, I was working with this test XML:

<root>
  <something uid="2" oid="1"/>
  <something uid="1" oid="2"/>
  <something uid="3" oid="3"/>
</root>

Jon

"I don't regret this, but I both rue and lament it.