Split one out-file into multiple xmls after n elements - xslt

Question

I am using a 3rd party software to generate an XML-file. This software allows to use a post-processor in form of XSLT (2.0).
My output files are rather huge, often reaching multiple hundred MB and several million of lines. I want to chunk my output files and have 1 file after each (lets say 10 products) instead of all in one file.
I found a smiliar thread here: Split one XML file to multiple XML File with XSLT but since I'm completly new to XSLT, I can't figure out on how to give a specific range at which the files will be splitted. I assume xsl:for-each select="document/file"> from the given example is the expression where to look, but I'm not certain either.
A simple XML looks a bit like this:
<Products>
<Product ID="123" UserType="ITEM">
<Name>First Product</Name>
<Values>
<Value AttributeID="someAttribute">foo</Value>
<Value AttributeID="AnotherAttribute">bar</Value>
</Values>
</Product>
<Product ID="456" UserType="ITEM">
<Name>Second Product</Name>
<Values>
<Value AttributeID="someAttribute">foo</Value>
<Value AttributeID="AnotherAttribute">bar</Value>
</Values>
</Product>
</Products>
As mentioned above, there are multiple thousands of products and for the sake of a clean overview, I left out the nodes before and after the <Products>-node.
How can I split my one given output-file to N files, which are split after lets say 10 products?

Answer 1

Assuming the Products element is a child of the root element you could use e.g.
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="#all"
expand-text="yes">
<xsl:param name="size" as="xs:integer" select="2"/>
<xsl:output method="xml" indent="yes"/>
<xsl:template match="/*">
<xsl:for-each-group select="*" group-adjacent="boolean(self::Products)">
<xsl:choose>
<xsl:when test="not(current-grouping-key()) and position() = 1">
<xsl:result-document href="headers.xml">
<Root>
<xsl:copy-of select="current-group()"/>
</Root>
</xsl:result-document>
</xsl:when>
<xsl:when test="current-grouping-key()">
<xsl:for-each-group select="current-group()/Product" group-by="(position() - 1) idiv $size">
<xsl:result-document href="chunk-{position()}.xml">
<Products>
<xsl:copy-of select="current-group()"/>
</Products>
</xsl:result-document>
</xsl:for-each-group>
</xsl:when>
<xsl:when test="not(current-grouping-key()) and position() = last()">
<xsl:result-document href="footers.xml">
<Root>
<xsl:copy-of select="current-group()"/>
</Root>
</xsl:result-document>
</xsl:when>
</xsl:choose>
</xsl:for-each-group>
</xsl:template>
</xsl:stylesheet>