XSLT 1.0 sort on filtered XML data

Question

Ok so based on this question XSLT 1.0 sort elements I cannot figure out why the following is not working:

I have the following XML:

<?xml version="1.0" encoding="UTF-8"?>
<viewentries>
    <viewentry>
        <entrydata name="Waste">
            <text>Bric-a-Brac</text>
        </entrydata>
        <entrydata name="Disposal">
            <text/>
        </entrydata>
    </viewentry>
    <viewentry>
        <entrydata name="Waste">
            <textlist>
                <text>Paper</text>
                <text>Glass</text>
            </textlist>
        </entrydata>
        <entrydata name="Disposal">
            <text/>
        </entrydata>
    </viewentry>
        <viewentry>
        <entrydata name="Waste">
            <textlist>
                <text>Paper</text>
                <text>Cans</text>
            </textlist>
        </entrydata>
        <entrydata name="Disposal">
                <text>Washing Machines</text>
                <text>Cars</text>
        </entrydata>
    </viewentry>
</viewentries>

And the following XSLT:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" indent="yes"/>

    <xsl:key name="k1" match="entrydata[@name = 'Waste' or @name = 'Disposal']//text" use="concat(ancestor::entrydata/@name, '|', .)"/>

    <xsl:template match="viewentries">
        <categories>
            <xsl:apply-templates/>
        </categories>
    </xsl:template>

    <xsl:template match="viewentry">
        <xsl:apply-templates select="entrydata[@name =  'Waste' or @name = 'Disposal']//text
      [generate-id() = generate-id(key('k1', concat(ancestor::entrydata/@name, '|', .))[1])]">
            <xsl:sort select="."/>
        </xsl:apply-templates>
    </xsl:template>

    <xsl:template match="text[normalize-space() != '']">
        <category type="{ancestor::entrydata/@name}">
            <xsl:apply-templates/>
        </category>
    </xsl:template>

</xsl:stylesheet>

This gives the following output:

<?xml version="1.0" encoding="UTF-8"?>
<categories>
    <category type="Waste">Bric-a-Brac</category>
    <category type="Waste">Glass</category>
    <category type="Waste">Paper</category>
    <category type="Waste">Cans</category>
    <category type="Disposal">Cars</category>
    <category type="Disposal">Washing Machines</category>
</categories>

I need the output in sorted order:

<?xml version="1.0" encoding="UTF-8"?>
<categories>
    <category type="Waste">Bric-a-Brac</category>
    <category type="Waste">Cans</category>
    <category type="Disposal">Cars</category>
    <category type="Waste">Glass</category>
    <category type="Waste">Paper</category>
    <category type="Disposal">Washing Machines</category>
</categories>

What am I doing wrong ?

EDIT:

It seems to be sorting based on the first <text> value of <entrydata> only instead of all <text> values.

However this stylesheet works fine:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" indent="yes"/>
    <xsl:key name="k1" match="entrydata[@name = 'Waste' or @name = 'Disposal']//text" use="concat(ancestor::entrydata/@name, '|', .)"/>

    <xsl:template match="viewentries">
        <categories>
            <xsl:apply-templates select="viewentry/entrydata[@name =  'Waste' or @name = 'Disposal']//text
            [generate-id() = generate-id(key('k1', concat(ancestor::entrydata/@name, '|', .))[1])]">
                <xsl:sort select="."/>          
            </xsl:apply-templates>
        </categories>
    </xsl:template>

    <xsl:template match="text[normalize-space() != '']">
        <category type="{ancestor::entrydata/@name}">
            <xsl:value-of select="."/>
        </category>
    </xsl:template>

</xsl:stylesheet>

Can someone explain why the first example doesn't work but the second example does.

Answer 1

Can anyone explain why applying the sort to the first template works, but when applying it to the second template like in my original question it doesn't ????

Here is your "second template":

<xsl:template match="text[normalize-space() != '']">
    <category type="{ancestor::entrydata/@name}">
        <xsl:apply-templates>
                <xsl:sort select="."/>            
        </xsl:apply-templates>
    </category>
</xsl:template>

Here you want to sort the children of the current node by their string value.

However, in the provided XML document any text element has a single text-node child -- therefore there isn't anything to sort!

In this and in the previous question you commit the same error -- trying to sort the children of the elements that must be sorted -- you are sorting too-late.

Remember:

   <xsl:apply-templates/>

is an abbreviation for:

   <xsl:apply-templates select="child::node()"/>

So, this means: apply templates to my children" -- not "apply templates to me".

Update: Here is a correct solution to the problem:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:key name="kCatVal" match="text[text()]" use="concat(../@name, '+', .)"/>

 <xsl:template match="/">
  <categories>
   <xsl:apply-templates select=
    "//text[generate-id()
               =
                generate-id(key('kCatVal',
                                 concat(../@name, '+', .)
                                 )[1]
                            )
                ]">
          <xsl:sort/>
    </xsl:apply-templates>
  </categories>
 </xsl:template>

 <xsl:template match="text">
        <category type="{../@name}"><xsl:value-of select="."/></category>
  </xsl:template>
</xsl:stylesheet>

When applied on the provided XML document:

<viewentries>
    <viewentry>
        <entrydata name="Waste">
            <text>Bric-a-Brac</text>
        </entrydata>
        <entrydata name="Disposal">
            <text/>
        </entrydata>
    </viewentry>
    <viewentry>
        <entrydata name="Waste">
            <textlist>
                <text>Paper</text>
                <text>Glass</text>
            </textlist>
        </entrydata>
        <entrydata name="Disposal">
            <text/>
        </entrydata>
    </viewentry>
    <viewentry>
        <entrydata name="Waste">
            <textlist>
                <text>Paper</text>
                <text>Cans</text>
            </textlist>
        </entrydata>
        <entrydata name="Disposal">
            <text>Washing Machines</text>
            <text>Cars</text>
        </entrydata>
    </viewentry>
</viewentries>

the wanted, correct result is produced:

<categories>
   <category type="Waste">Bric-a-Brac</category>
   <category type="">Cans</category>
   <category type="Disposal">Cars</category>
   <category type="">Glass</category>
   <category type="">Paper</category>
   <category type="Disposal">Washing Machines</category>
</categories>

Explanation:

This kind of grouping requires indexing based on a composite key that has two parts. Therefore the use attribute of xsl:key is specified as the concatenation of these two parts, joined together by a character that we know cannot be present in any of their values (to avoid false-positives when a value of the first key component is a prefix of a value of the second key component).