Generic XSLT transform to manipulate similar XML data - xslt

Question

We have a tool which is producing an unwanted XML element and we are using XSLT to translate it to the required format.
We are writing a different XSLT for every XML generated by the file. e.g. one for the Customers XML, one for the Orders XML and so on.
Below are a couple of XML data files produced by the tool and the actual output expected
Customers
Tool-generated XML
<Message>
<Data>
<CustomerArray>
<Customer>
<X>
<Name>John</Name>
<Id>100</Id>
<Roles>
<Role>
<X>Manager</X>
<X>Architect</X>
</Role>
</Roles>
</X>
<X>
<Name>Doe</Name>
<Id>102</Id>
<Roles>
<Role>
<X>Supervisor</X>
<X>Admin</X>
</Role>
</Roles>
</X>
</Customer>
</CustomerArray>
</Data>
</Message>
Required XML data
<Message>
<Data>
<CustomerArray>
<Customer>
<Name>John</Name>
<Id>100</Id>
<Roles>
<Role>Manager</Role>
<Role>Architect</Role>
</Roles>
</Customer>
<Customer>
<Name>Doe</Name>
<Id>102</Id>
<Roles>
<Role>Supervisor</Role>
<Role>Admin</Role>
</Roles>
</Customer>
</CustomerArray>
</Data>
</Message>
Orders
Tool-generated XML
<Message>
<Orders>
<Order>
<X>
<OrderNumber>O123</OrderNumber>
<CustomerID>C100</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>10.0</UnitPrice>
</X>
<X>
<OrderNumber>O456</OrderNumber>
<CustomerID>C107</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>5.0</UnitPrice>
</X>
</Order>
</Orders>
</Message>
Required XML data
<Message>
<Orders>
<Order>
<OrderNumber>O123</OrderNumber>
<CustomerID>C100</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>10.0</UnitPrice>
</Order>
<Order>
<OrderNumber>O456</OrderNumber>
<CustomerID>C107</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>5.0</UnitPrice>
</Order>
</Orders>
</Message>
The unwanted element X can come at any level.
Is it possible to write a generic XSLT transform to achieve this result across all XML input? For instance, where an X is found, replace it with the parent tag and then delete the parent tag.

Answer 1

You need to write an identity transform with an explicit template for all nodes that have any X children so that they can be replicated.
This transform does what you asked. It uses the variable name to save the name of the element that is parent to the X to avoid writing the more obscure name(current()) when it comes to generating each output element.
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:strip-space elements="*"/>
<xsl:output method="xml" indent="yes" encoding="UTF-8" omit-xml-declaration="yes"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
<xsl:template match="*[X]">
<xsl:variable name="name" select="name()"/>
<xsl:for-each select="X">
<xsl:element name="{$name}">
<xsl:apply-templates/>
</xsl:element>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
output
Customers
<Message>
<Data>
<CustomerArray>
<Customer>
<Name>John</Name>
<Id>100</Id>
<Roles>
<Role>Manager</Role>
<Role>Architect</Role>
</Roles>
</Customer>
<Customer>
<Name>Doe</Name>
<Id>102</Id>
<Roles>
<Role>Supervisor</Role>
<Role>Admin</Role>
</Roles>
</Customer>
</CustomerArray>
</Data>
</Message>
Orders
<Message>
<Orders>
<Order>
<OrderNumber>O123</OrderNumber>
<CustomerID>C100</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>10.0</UnitPrice>
</Order>
<Order>
<OrderNumber>O456</OrderNumber>
<CustomerID>C107</CustomerID>
<Quantity>100</Quantity>
<UnitPrice>5.0</UnitPrice>
</Order>
</Orders>
</Message>

Answer 2

Here is a slightly simpler/shorter solution, which also handles correctly the case when a X can have non X sibling elements:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="*[X]"><xsl:apply-templates/></xsl:template>
<xsl:template match="X">
<xsl:element name="{name(..)}">
<xsl:apply-templates select="node()|#*"/>
</xsl:element>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied to the following XML document (the first of the provided ones, with one non-X sibling added to the X elements:
<Message>
<Data>
<CustomerArray>
<Customer>
<X>
<Name>John</Name>
<Id>100</Id>
<Roles>
<Role>
<X>Manager</X>
<X>Architect</X>
</Role>
</Roles>
</X>
<somethingElse/>
<X>
<Name>Doe</Name>
<Id>102</Id>
<Roles>
<Role>
<X>Supervisor</X>
<X>Admin</X>
</Role>
</Roles>
</X>
</Customer>
</CustomerArray>
</Data>
</Message>
the wanted, correct result is produced:
<Message>
<Data>
<CustomerArray>
<Customer>
<Name>John</Name>
<Id>100</Id>
<Roles>
<Role>Manager</Role>
<Role>Architect</Role>
</Roles>
</Customer>
<somethingElse/>
<Customer>
<Name>Doe</Name>
<Id>102</Id>
<Roles>
<Role>Supervisor</Role>
<Role>Admin</Role>
</Roles>
</Customer>
</CustomerArray>
</Data>
</Message>
Do note that the solution by Borodin loses the somethingElse element.