[xsl] for-each-group dropping one element (my inability to structure a test correctly)

Subject: [xsl] for-each-group dropping one element (my inability to structure a test correctly)
From: "Mark Wilson" <mark@xxxxxxxxxxxx>
Date: Sun, 7 Feb 2010 00:09:31 -0800
Hi all,
I have been at this for about six hours.

As written, the style sheet does not produce the element marked "Missing element" in Listing 3 (the output ) and as "Not output" in Listing one (source document). The problem is marked "My problem" in the Listing 2 (style sheet).

I Know that my problem is that I am telling the style sheet to give me only the first <Data> element. What I don't know is how to tell it to give me all of the <Data> elements that meet the <xsl:if> test, but none of the <Data> element that do not meet that test. Or have I just set everything up wrong to start with?

Any help would be appreciated
Mark

Listing 1: Input
<?xml version="1.0" encoding="UTF-8"?>
<List >
   <Item plate="1" position="1">
       <Feature>
           <Location>
               <Element>rays</Element>
           </Location>
           <Data>dot below the rays under TA</Data>
       </Feature>
       <Feature>
           <Location>
               <Element>rays</Element>
               <SubDiv>main</SubDiv>
           </Location>
           <Data>main ray swollen at both ends</Data>
       </Feature>
   </Item>
   <Item plate="2" position="1">
       <Feature>
           <Location>
               <Element>rays</Element>
           </Location>
           <Data>dot below the rays under S</Data> <!-- Not output -->
       </Feature>
   </Item>
   <Item plate="1" position="2">
       <Feature>
           <Location>
               <Element>rays</Element>
               <SubDiv>main</SubDiv>
           </Location>
           <Data>main ray thicker in the middle</Data>
       </Feature>
   </Item>
</List>

Listing 2: Style Sheet
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; xmlns:xs="http://www.w3.org/2001/XMLSchema"; exclude-result-prefixes="xs" version="2.0">


<xsl:template match="List">
<List>
<xsl:for-each-group select="Item/Feature" group-by="Location/Element">
<xsl:sort select="current-grouping-key()"/>
<Item>
<Feature>
<xsl:copy-of select="Location/Element" copy-namespaces="no"/>


<xsl:if test="not(Location/Element/following-sibling::SubDiv)">
<Description>
<xsl:copy-of select="Data" copy-namespaces="no"/><!-- My Problem -->
</Description>
</xsl:if>


<xsl:for-each-group select="current-group()" group-by="Location/SubDiv">
<xsl:sort select="current-grouping-key()"/>
<Level1>
<xsl:copy-of select="Location/SubDiv" copy-namespaces="no"/>
<Description>
<xsl:copy-of select="current-group()/Data" copy-namespaces="no"/>
</Description>
</Level1>
</xsl:for-each-group>
</Feature>
</Item>
</xsl:for-each-group>
</List>
</xsl:template>
</xsl:stylesheet>


Listing 3: Output
<?xml version="1.0" encoding="UTF-8"?>
<List>
   <Item>
       <Feature>
           <Element>rays</Element>
           <Description>
               <Data>dot below the rays under TA</Data>
<!-- Missing Element: <Data>dot below the rays under S</Data> goes here -->
           </Description>
           <Level1>
               <SubDiv>main</SubDiv>
               <Description>
                   <Data>main ray swollen at both ends</Data>
                   <Data>main ray thicker in the middle</Data>
               </Description>
           </Level1>
       </Feature>
   </Item>
</List>

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